The operating parameters of the steam turbine control system must meet Russian state standards and technical specifications for the supply of turbines.
The degree of uneven regulation of steam pressure in regulated extractions and back pressure must satisfy the consumer's requirements, agreed upon with the turbine manufacturer, and prevent the safety valves (devices) from tripping.
All inspections and tests of the turbine overspeed control and protection system must be carried out in accordance with the instructions of the turbine manufacturers and current governing documents.
The safety circuit breaker must operate when the turbine rotor speed increases by 10 - 12% above the nominal value or to the value specified by the manufacturer.
When the safety circuit breaker is triggered, the following must close:
stop, control (stop-control) valves for fresh steam and reheat steam;
stop (shut-off), control and check valves, as well as control diaphragms and steam extraction dampers;
shut-off valves on steam pipelines connecting with third-party sources of steam.
The turbine protection system against increased rotor speed (including all its elements) must be tested by increasing the rotation speed above the rated speed in the following cases:
a) after installation of the turbine;
b) after major repairs;
c) before testing the control system by load shedding with disconnection of the generator from the network;
d) during startup after disassembling the safety circuit breaker;
e) during startup after a long (more than 3 months) idle time of the turbine, if it is not possible to check the operation of the strikers of the safety circuit breaker and all protection circuits (with impact on the actuators) without increasing the rotation speed above the nominal one;
e) during startup after the turbine has been idle in reserve for more than 1 month. if it is not possible to check the operation of the safety breakers and all protection circuits (with impact on the executive bodies) without increasing the rotation speed above the nominal one;
g) during startup after disassembling the control system or its individual components;
h) during scheduled tests (at least once every 4 months).
In cases “g” and “h”, it is allowed to test the protection without increasing the rotation speed above the nominal (in the range specified by the turbine manufacturer), but with mandatory verification of the operation of all protection circuits.
Tests of turbine protection by increasing rotation speed must be carried out under the guidance of the workshop manager or his deputy.
The tightness of the live steam stop and control valves should be checked by testing each group separately.
The density criterion is the turbine rotor speed, which is set after the valves being tested are completely closed at full (nominal) or partial steam pressure in front of these valves. The permissible value of the rotation speed is determined by the manufacturer's instructions or current governing documents, and for turbines, the testing criteria for which are not specified in the manufacturer's instructions or current governing documents should not be higher than 50% of the nominal value at the nominal parameters in front of the valves being tested and the nominal exhaust pressure pair.
When all stop and control valves are closed simultaneously and the fresh steam and back pressure (vacuum) are at nominal parameters, passing steam through them should not cause rotation of the turbine rotor.
Checking the tightness of the valves should be carried out after installing the turbine, before testing the safety circuit breaker by increasing the rotation speed, before stopping the turbine for a major overhaul, during startup after it, but at least once a year. If signs of a decrease in valve density are detected during turbine operation, an extraordinary check of their density must be carried out.
Stop and control valves for fresh steam, stop (shut-off) and control valves (diaphragms) for steam extraction, shut-off valves on steam pipelines connecting with third-party steam sources should move: to full speed- before starting the turbine and in cases provided for by the manufacturer’s instructions; for part of the stroke - every day during turbine operation.
When moving the valves to full stroke, the smoothness of their movement and seating must be checked.
The tightness of the check valves of regulated extractions and the operation of the safety valves of these extractions must be checked at least once a year and before testing the turbine for load shedding.
Check valves of regulated heating steam extractions, which are not connected to the extractions of other turbines, ROU and other steam sources, do not need to be tested for density unless there are special instructions from the manufacturer.
The seating of check valves of all extractions must be checked before each start-up and when stopping the turbine, and during normal operation periodically according to a schedule determined by the technical manager of the power plant, but at least once every 4 months.
If the check valve is faulty, operation of the turbine with appropriate steam extraction is not allowed.
Checking the closing time of stop (protective, shut-off) valves, as well as reading the characteristics of the control system with the turbine stopped and when it is idling, should be carried out:
after installation of the turbine;
immediately before and after a major overhaul of the turbine or repair of the main components of the control or steam distribution system.
Tests of the turbine control system by instantaneous load shedding corresponding to the maximum steam flow must be performed: 
when accepting turbines into operation after installation;
after reconstruction that changes the dynamic characteristics of the turbine unit or the static and dynamic characteristics of the control system.
If deviations in the actual characteristics of regulation and protection from standard values are detected, valve closing time increases beyond those specified by the manufacturer or in local instructions, or their density deteriorates, the causes of these deviations must be identified and eliminated.
The operation of turbines with a power limiter put into operation is permitted as a temporary measure only under the conditions of the mechanical condition of the turbine installation with the permission of the technical manager of the power plant. In this case, the turbine load must be lower than the limiter setting by at least 5%.
Shut-off valves installed on the lines of the lubrication, regulation and sealing system of the generator, the erroneous switching of which can lead to shutdown or damage to the equipment, must be sealed in the operating position.
Before starting up a turbine after a medium or major overhaul, the serviceability and readiness to turn on the main and auxiliary equipment, instrumentation, remote and automatic control devices, process protection devices, interlocks, information and operational communications must be checked. Any defects identified must be corrected.
Before starting a turbine from a cold state (after it has been in reserve for more than 3 days), the following must be checked: the serviceability and readiness for switching on of equipment and instrumentation, as well as the operability of remote and automatic control devices, process protection devices, interlocks, information and operational communications; passing technological protection commands to all actuators; serviceability and readiness to turn on those facilities and equipment on which repair work was carried out during downtime. Any malfunctions identified in this case must be eliminated before start-up.
The start-up of the turbine should be supervised by the workshop shift supervisor or senior machinist, and after a major or medium repair - by the workshop supervisor or his deputy.
Starting the turbine is not allowed in the following cases:
deviations of indicators of the thermal and mechanical conditions of the turbine from the permissible values regulated by the turbine manufacturer;
malfunction of at least one of the protections acting to stop the turbine;
the presence of defects in the control and steam distribution systems, which can lead to turbine acceleration;
malfunction of one of the oil lubrication pumps, regulation, generator seals or their automatic switching devices (AVR);
deviations in oil quality from the standards for operating oils or a drop in oil temperature below the limit set by the manufacturer;
deviations in fresh steam quality chemical composition from normal
Without turning on the turning device, supplying steam to the turbine seals, discharging hot water and steam into the condenser, and supplying steam to warm up the turbine are not allowed. The conditions for supplying steam to a turbine that does not have a shaft turning device are determined by local instructions. 
The discharge of the working medium from the boiler or steam lines into the condenser and the supply of steam to the turbine to start it must be carried out at steam pressures in the condenser specified in the instructions or other documents of the turbine manufacturers, but not higher than 0.6 (60 kPa).
When operating turbine units, the mean square values of the vibration velocity of the bearing supports should be no higher than 4.5 mm s -1.
If the standard vibration value is exceeded, measures must be taken to reduce it within no more than 30 days.
When vibration exceeds 7.1 mm s -1, it is not allowed to operate turbine units for more than 7 days, and when vibration is 11.2 mm s -1, the turbine must be turned off by protection or manually.
The turbine must be stopped immediately if, in steady state, there is a simultaneous sudden change in the vibration of the rotation frequency of two supports of one rotor, or adjacent supports, or two vibration components of one support by 1 mm s -1 or more from any initial level.
The turbine must be unloaded and stopped if, within 13 days, there is a smooth increase in any vibration component of one of the bearing supports by 2 mm·s -1.
Operation of the turbine unit during low-frequency vibration is unacceptable. If low-frequency vibration exceeding 1 mm·s -1 occurs, measures must be taken to eliminate it.
Temporarily, until equipped with the necessary equipment, vibration control based on the range of vibration displacement is allowed. In this case, long-term operation is allowed with a vibration range of up to 30 microns at a rotation speed of 3000 and up to 50 microns at a rotation speed of 1500; a change in vibration by 12 mm s -1 is equivalent to a change in the amplitude of vibrations by 1020 µm at a rotation speed of 3000 and 2040 µm at a rotation speed of 1500.
Vibration of turbine units with a power of 50 MW or more should be measured and recorded using stationary equipment for continuous vibration monitoring of bearing supports that meets state standards.
To monitor the condition of the turbine flow path and its contamination with salts, the values of steam pressure in the control stages of the turbine should be checked at least once a month at close to nominal steam flow rates through the controlled compartments.
The increase in pressure in the control stages compared to the nominal one at a given steam flow rate should be no more than 10%. In this case, the pressure should not exceed the limit values set by the manufacturer.
When the pressure limits in the control stages are reached due to salt deposits, the turbine flow path must be flushed or cleaned. The method of flushing or cleaning should be selected based on the composition and nature of the deposits and local conditions.
During operation, the efficiency of a turbine installation must be constantly monitored through a systematic analysis of indicators characterizing the operation of the equipment.
To identify the reasons for the decrease in the efficiency of a turbine installation and assess the effectiveness of repairs, operational (express) tests of the equipment must be carried out.
The turbine must be immediately stopped (disconnected) by personnel if the protection fails or is absent in the following cases: 
increasing the rotor speed above the safety circuit breaker setting;
unacceptable axial shift of the rotor;
unacceptable change in the position of the rotors relative to the cylinders;
unacceptable decrease in oil pressure (fire-resistant liquid) in the lubrication system;
unacceptable drop in oil level in the oil tank;
an unacceptable increase in oil temperature at the drain from any bearing, generator shaft seal bearings, or any turbo unit thrust bearing block;
ignition of oil and hydrogen on a turbine unit;
an unacceptable decrease in the oil-hydrogen pressure difference in the turbogenerator shaft seal system;
an unacceptable decrease in the oil level in the damper tank of the oil supply system for the turbogenerator shaft seals;
turning off all oil pumps of the hydrogen cooling system of the turbogenerator (for non-injector oil supply schemes for seals);
shutdown of the turbogenerator due to internal damage;
unacceptable increase in pressure in the condenser;
unacceptable pressure drop at the last stage of turbines with back pressure;
sudden increase in vibration of the turbine unit;
the appearance of metallic sounds and unusual noises inside the turbine or turbogenerator;
the appearance of sparks or smoke from bearings and end seals of a turbine or turbogenerator;
unacceptable decrease in the temperature of fresh steam or steam after reheating;
the appearance of hydraulic shocks in the steam lines of fresh steam, reheating or in the turbine;
detection of a rupture or through crack in non-disconnectable sections of oil pipelines and pipelines of the steam-water path, steam distribution units;
stopping the flow of cooling water through the turbogenerator stator;
unacceptable reduction in cooling water consumption for gas coolers;
loss of voltage on remote and automatic control or at all instrumentation;
the appearance of a circular fire on the slip rings of the rotor of a turbogenerator, auxiliary generator or exciter manifold;
failure of the software and hardware complex of the automated process control system, leading to the impossibility of managing or monitoring all equipment of the turbine installation.
The need to break the vacuum when shutting down the turbine must be determined by local regulations in accordance with the manufacturer's instructions. 
The local instructions must provide clear instructions about unacceptable deviations in the values of controlled quantities for the unit.
The turbine must be unloaded and stopped within a period determined by the technical manager of the power plant (with notification to the power system dispatcher), in the following cases:
jamming of stop valves of fresh steam or steam after reheating;
jamming of control valves or breakage of their rods; jamming of rotary diaphragms or check valves;
malfunctions in the control system;
disruption of the normal operation of auxiliary equipment, circuitry and communications of the installation, if eliminating the causes of the disruption is impossible without stopping the turbine;
increase in vibration of supports above 7.1 mm·s -1;
identifying malfunctions of technological protections acting to stop equipment;
detection of oil leaks from bearings, pipelines and fittings that create a fire hazard;
detection of fistulas in sections of steam-water pipelines that cannot be disconnected for repair;
deviations in the quality of fresh steam in terms of chemical composition from the norms;
detection of unacceptable concentrations of hydrogen in bearing housings, conductors, oil tank, as well as hydrogen leakage from the turbogenerator housing that exceeds the norm.
For each turbine, the duration of the rotor run-out must be determined during shutdown with normal exhaust steam pressure and during shutdown with vacuum failure. When changing this duration, the reasons for the deviation must be identified and eliminated. The duration of the run-down must be monitored during all shutdowns of the turbine unit.
When placing a turbine into reserve for a period of 7 days or more, measures must be taken to preserve the equipment of the turbine installation.
Thermal testing of steam turbines must be carried out.
REPAIR OF STEAM TURBINES
BRIEF DESCRIPTION OF THE COURSE: The program course provides for advanced training of working personnel participating in technical operation main and auxiliary equipment of turbine units.
The training course is calculated for vocational school repair mechanics of categories 3,4,5,6 according to ETKS, as well as for management personnel (shift supervisors, vocational school repairmen).
Course duration training 40 hours
GOALS: Increase the level of theoretical knowledge and practical skills of students.
FORMS OF TRAINING: Lectures, active participation of students in the learning process, debates, solving situational problems.
PARTICIPANTS:. PTU repair mechanics of categories 3,4,5,6 according to ETKS, as well as management personnel (shift supervisors, PTU repairmen).
SUMMARIZING: At the end of the course, students are surveyed and tested.
Lesson topic | Lesson Objective | Field of study | Teaching Techniques | Means of education | Continue duration, in minutes |
|
Psychological testing for the level of logical and mathematical thinking | Determine the level of logical and mathematical thinking of each listener | educational | Psychological tests | Handout, test forms. | ||
CYLINDER BODY REPAIR | TYPICAL DESIGNS AND BASIC MATERIALS: (Types of cylinders, Materials used, Fastening units). Typical cylinder defects and reasons for their occurrence. Opening the cylinders. BASIC OPERATIONS PERFORMED WHEN REPAIRING CYLINDERS: (Inspection, Metal inspection, Checking cylinder warpage, determining corrections for centering the flow part, Determining the magnitude of vertical movements of parts of the flow part when tightening the housing flanges, Determining and correcting the reaction of the cylinder supports Elimination of defects). CONTROL ASSEMBLY CLOSING ASSEMBLY AND SEALING OF FLANGE JOINTS OF CONNECTED PIPELINES | Cognitive | Lecture, debate | Handout | ||
REPAIR OF DIAPHRAGM AND CHAPS | TYPICAL DESIGNS AND BASIC MATERIALS. CHARACTERISTIC DEFECTS OF DIAPHRAGM AND CHAMBERS AND THE REASONS FOR THEIR APPEARANCE. BASIC OPERATIONS PERFORMED WHEN REPAIRING DIAPHRAGM AND CHAPS: (Disassembly and inspection, elimination of defects, Assembly and alignment ). | Cognitive | Handout | |||
REPAIR OF SEALS | TYPICAL DESIGNS AND BASIC MATERIALS CHARACTERISTIC DEFECTS OF SEALS AND REASONS FOR THEIR APPEARANCE. BASIC OPERATIONS PERFORMED WHEN REPAIRING SEALS: (Inspection, Checking and adjusting radial clearances, Adjusting the linear size of the ring of seal segments, Replacing the antennae of the seals installed in the rotor, Adjusting axial clearances, Restoring clearances in over-band seals) | Cognitive | Handout | |||
BEARING REPAIR | REPAIR OF SUPPORT BEARINGS: Typical designs and main materials of support bearings) Characteristic defects of support bearings and their causes. Basic operations performed when repairing support bearings: (Opening bearing housings, their inspection and repair, Inspection of liners, Checking interference and clearances). Movement of bearings when aligning the rotors Closing the bearing housings. | Cognitive | Handout | |||
BEARING REPAIR | REPAIR OF THRUST BEARINGS. Typical designs and basic materials of thrust bearings. Characteristic defects of the thrust part of bearings and the reasons for their occurrence. Inspection and repair. Control assembly of the thrust bearing. CHECKING THE AXIAL ROTOR RUN. REFILLING OF BABBITT SUPPORT BEARING INSERTS AND THRUST BEARING SHOES. SPRAYING OF INSERTS BORINGS. Oil seal repair | Cognitive | Lecture, debate | Handout | ||
ROTOR REPAIR | TYPICAL DESIGNS AND BASIC MATERIALS CHARACTERISTIC DEFECTS OF ROTORS AND REASONS FOR THEIR APPEARANCE. DISASSEMBLING, CHECKING BATTLES AND REMOVING ROTORS. BASIC OPERATIONS PERFORMED WHEN REPAIRING ROTORS: ( Audit, Metal inspection, Defect elimination). LAYING ROTORS INTO A CYLINDER. | Cognitive | Lecture, debate | Handout | ||
REPAIR OF WORKING BLADES. | TYPICAL DESIGNS AND BASIC MATERIALS OF WORK BLADES. CHARACTERISTIC DAMAGES TO WORK BLADES AND THE REASONS FOR THEIR APPEARANCE. BASIC OPERATIONS PERFORMED WHEN REPAIRING WORK BLADES: (Inspection, Metal inspection, Repair and restoration, Reblading of the impeller, Installation of connections). | Cognitive | Lecture, debate | Handout | ||
REPAIR OF ROTOR COUPLINGS | TYPICAL DESIGNS AND BASIC MATERIALS OF COUPLINGS. CHARACTERISTIC DEFECTS OF COUPLINGS AND REASONS FOR THEIR APPEARANCE. BASIC OPERATIONS PERFORMED WHEN REPAIRING COUPLINGS: (Disassembly and inspection, Metal inspection, Features of removing and fitting coupling halves, Elimination of defects, Features of repair of spring couplings). ASSEMBLY OF THE COUPLING AFTER REPAIR. "PENDULUM" CHECKING ROTORS. | Cognitive | Lecture, debate | Handout | ||
TURBINE ALIGNMENT | Centering tasks. Carrying out alignment measurements on coupling halves. Determination of the position of the rotor relative to the turbine stator. Calculation of the alignment of a pair of rotors. Features of alignment of two rotors with three support bearings. Methods for calculating the alignment of turbine shafting. | Cognitive, | Lecture, exchange of experience | Handout | ||
NORMALIZATION OF THERMAL EXPANSIONS OF TURBINES | DEVICE AND OPERATION OF THE THERMAL EXPANSION SYSTEM. MAIN CAUSES OF DISRUPTIONS IN THE NORMAL OPERATION OF THE THERMAL EXPANSION SYSTEM. METHODS FOR NORMALIZING THERMAL EXPANSIONS. BASIC OPERATIONS FOR NORMALIZING THERMAL EXPANSIONS PERFORMED DURING TURBINE REPAIR. | Cognitive, | Lecture, exchange of experience | Handout | ||
NORMALIZATION OF THE VIBRATION STATE OF A TURBO UNIT | MAIN CAUSES OF VIBRATION. VIBRATION AS ONE OF THE CRITERIA FOR EVALUATING THE CONDITION AND QUALITY OF TURBINE REPAIR. MAIN DEFECTS AFFECTING CHANGES IN THE VIBRATIONAL STATE OF THE TURBINE AND THEIR SIGNS. METHODS FOR NORMALIZING TURBO UNIT VIBRATION PARAMETERS. | Cognitive | Lecture, exchange of experience | Handout | ||
REPAIR AND ADJUSTMENT OF AUTOMATIC CONTROL AND STEAM DISTRIBUTION SYSTEMS | What documents and within what time frame must be drawn up and approved for the repair of ACS and steam distribution before the start of repairs. What work is performed during the repair of the ATS and in preparation for it. Documentation for ATS repair. General requirements to SAR. Removing the steam distribution characteristics. Removing the characteristics of the ATS. | Cognitive | Lecture, exchange of experience | Handout | ||
Repair of cam distribution mechanism: (Main defects of cam distribution mechanisms) Repair of control valves: (Inspection of the stem and valve, Inspection of lever bearings and rollers). Steam distribution materials. | Handout | Lecture, exchange of experience | Handout | |||
REPAIR OF STEAM DISTRIBUTION SYSTEM ELEMENTS | SERVOMOTORS. General requirements for servomotors. The most common defects of servomotors with one-sided fluid supply. The main defects of servomotors with double-sided fluid supply. | Handout | Lecture, exchange of experience | Handout | ||
TESTING | ||||||
APPENDICES TO THE PROGRAM:
1. Application. Presentation material used in training.
2. Application. Tutorial.
n1.doc
Ministry of Education Russian FederationGOU Ural State Technical University - UPI
V. N. Rodin, A. G. Sharapov, B. E. Murmansky, Yu. A. Sakhnin, V. V. Lebedev, M. A: Kadnikov, L. A. Zhuchenko
REPAIR OF STEAM TURBINES
Tutorial
Under the general editorship of Yu. M. Brodov V. N. Rodin
Ekaterinburg 2002
NOTATIONS AND ABBREVIATIONS
TPP - thermal power station
NPP - nuclear power plant
PPR - scheduled preventive maintenance
NTD - normative and technical documentation
PTE - rules of technical operation
STOIR - maintenance and repair system
ATS - automatic control system
ERP - energy repair enterprise
CCR - centralized repair shop
RMU - mechanical repair department
RD - guidance document
OPPR - department for preparation and repairs
Instrumentation - control and measuring instruments
LMZ - Leningrad Mechanical Plant
HTZ - Kharkov Turbine Plant
TMZ - Turbomotor Plant
VTI - All-Union Thermal Engineering Institute
HPC - high pressure cylinder
CSD - medium pressure cylinder
LPC - low pressure cylinder
LPH - low pressure heater
HPH - high pressure heater
KTZ - Kaluga Turbine Plant
MPD - magnetic particle flaw detection
UZK - ultrasonic testing
TsKB "Energoprogress" - central design bureau "Energoprogress"
VPU - shaft turning device
HPR - high pressure rotor
RSD - medium pressure rotor
RND - low pressure rotor
HP - high pressure part
PSD - part of the average pressure
LLP - low pressure part
TV K - eddy current control
CD - color flaw detection
OTK - technical control department
THAT - technical specifications
MFL - metal fluoroplastic tape
LFV - low frequency vibration
GPZ - main steam valve
ZAB - safety valve spool
Efficiency - efficiency factor
KOS - solenoid check valve
WTO - recovery heat treatment
HERE. - tons of standard fuel
H.H. - idling
PREFACE
Energy, as a basic industry, determines the “health” of the country’s economy as a whole. The state of affairs in this industry has become more difficult in recent years. This is determined by a number of factors:
underutilization of equipment, which, as a rule, leads to the need to operate turbines (and other equipment of thermal power plants) at modes that do not correspond to maximum efficiency;
a sharp reduction in the commissioning of new capacities at thermal power plants;
moral and physical old age of almost 60% of energy equipment;
limited supply and sharp increase in the cost of fuel for thermal power plants;
lack of funds for equipment modernization and others.
Unfortunately, the discipline “Repair of steam turbines” is not included in the blocks of special disciplines of standards and curricula of most energy and power engineering specialties at universities. In a number of fundamental textbooks and teaching aids on steam turbines Almost no attention is paid to the issues of their repair. A number of publications do not reflect the current state of the issue. Undoubtedly, publications are very useful for studying the issue under consideration, but these works (essentially monographs) do not have an educational focus. Meanwhile, in recent years a number of directive and teaching materials regulating the repair of thermal power plants and, in particular, the repair of steam turbines.
Offered to the attention of readers tutorial"Repair of steam turbines" is intended for university students studying in the following specialties: 10.14.00 - Gas turbine, steam turbine plants and engines, 10.05.00 - Thermal power plants, 10.10.00 - Nuclear power plants and installations. The manual can also be used in the system of retraining and advanced training of engineering and technical personnel of thermal power plants and nuclear power plants.
basic principles of organizing turbine repairs;
reliability indicators, typical damage to turbines and the reasons for their occurrence;
standard designs and materials of steam turbine parts;
basic operations performed during the repair of all main parts of steam turbines. The issues of alignment, normalization of thermal expansion and vibration state are covered
In conclusion, directions for development are given that, according to the authors, will further improve the efficiency of the entire steam turbine repair system as a whole.
When working on the manual, the authors made extensive use of modern scientific and technical literature on thermal power plants and nuclear power plants, steam turbines and steam turbine units, as well as selected materials from turbine plants, JSC ORGRES and a number of repair energy enterprises.
The structure and methodology for presenting the material in the textbook were developed by Yu. M. Brodov.
The general edition of the textbook was carried out by Yu. M. Brodov and V. N. Rodin.
Chapter 1 was written by V. N. Rodin, chapters 2 and 12 by B. E. Murmansky, chapters 3; 4; 5; 6; 7; 9; I - A. G. Sharapov and B. E. Murmansky, chapter 8 - L. A. Zhuchenko and A. G. Sharapov, chapter 10 - A. G. Sharapov, chapter 13 - V. V. Lebedev and M. A . Kadnikov, chapter 14 - Yu. A. Sakhnin.
Comments on the tutorial will be gratefully received and should be posted onedit at the address: 620002, Ekaterinburg, K-2, st. Mira, 19 USTU-UPI, TeploenergeFaculty of Science, Department of Turbines and Engines. This textbook can be ordered from this address.
Chapter 1
TURBINE REPAIR ORGANIZATION
1.1. SYSTEM OF MAINTENANCE AND REPAIR OF POWER PLANT EQUIPMENT. BASIC CONCEPTS AND PROVISIONS
Reliable supply of energy to consumers is the key to the well-being of any state. This is especially true in our country with harsh climatic conditions, so uninterrupted and reliable operation of power plants is the most important task of energy production.
To solve this problem in the energy sector, maintenance and repair measures were developed that ensured long-term maintenance of equipment in working condition with the best economic performance of its operation and the minimum possible unscheduled stops for repairs. This system is based on carrying out scheduled preventive maintenance (PPR).
PPR systemis a set of activities for planning, preparing, organizing, monitoring and recording various types of maintenance and repair work energy equipment carried out according to a pre-drawn plan based on a standard volume repair work, ensuring trouble-free, safe and economical operation of power equipment of enterprises with minimal repair and operating costs. Essence PPR systems is that after a predetermined operating time, the need for equipment repairs is satisfied in a planned manner, by carrying out scheduled inspections, tests and repairs, the rotation and frequency of which are determined by the purpose of the equipment, the requirements for its safety and reliability, design features, maintainability and operating conditions.
The PPR system is built in such a way that each previous event is preventive in relation to the next one. According to distinguish Maintenance and equipment repair.
Maintenance- a set of operations to maintain the functionality or serviceability of the product when used for its intended purpose. It provides for the care of equipment: inspections, systematic monitoring of good condition, monitoring operating modes, compliance with operating rules, manufacturer's instructions and local operating instructions, eliminating minor faults that do not require shutting down the equipment, adjustments, and so on. Maintenance of existing power plant equipment includes the implementation of a set of measures for inspection, control, lubrication, and adjustment, which do not require the equipment to be taken out for routine repairs.
Maintenance (inspections, checks and tests, adjustment, lubrication, washing, cleaning) makes it possible to increase the warranty period of equipment before the next routine repair, and to reduce the amount of routine repairs.
Repair- a set of operations to restore the serviceability or performance of products and restore the resources of products or their components. Performing routine maintenance, in turn, prevents the need to schedule more frequent major repairs. This organization of planned repairs and maintenance operations makes it possible to constantly maintain equipment in trouble-free condition at minimal cost and without additional unplanned downtime for repairs.
Along with increasing the reliability and security of power supply, the most important task of repair maintenance is to improve or, in extreme cases, stabilize the technical and economic indicators of equipment. As a rule, this is achieved by stopping the equipment and opening its basic elements (boiler furnaces and convective heating surfaces, flow parts and turbine bearings).
It should be noted that the problems of reliability and efficiency of operation of thermal power plant equipment are so interconnected that it is difficult to separate them from one another.
For turbine equipment during operation, first of all, the technical and economic condition of the flow path is monitored, including:
salt deposits on the blades and nozzles, which cannot be eliminated by washing under load or at idle (silicon oxide, iron, calcium, magnesium, etc.); There are cases where, as a result of skidding, turbine power decreased by 25% in 10...15 days.
an increase in gaps in the flow part leads to a decrease in efficiency, for example, an increase in the radial gap in seals from 0.4 to 0.6 mm causes an increase in steam leakage by 50%.
During repairs, an important role is played by pressure testing and elimination of air suction points, as well as the use of various progressive seal designs in rotating air heaters. Repair personnel must, together with operating personnel, monitor air suction and, if possible, ensure their elimination not only during repairs, but also on operating equipment. Thus, a decrease (deterioration) in vacuum by 1% for a 500 MW power unit leads to excessive fuel consumption by approximately 2 tons. t./h, which is 14 thousand t.e. t./year, or in 2001 prices 10 million rubles.
The efficiency indicators of the turbine, boiler and auxiliary equipment are usually determined by conducting rapid tests. The purpose of these tests is not only to assess the quality of repairs, but also to regularly monitor the operation of equipment during the overhaul period. Analysis of the test results allows you to reasonably judge whether the unit should be stopped (or, if possible, individual elements of the installation should be switched off). When making decisions, the possible costs of shutdown and subsequent start-up, restoration work, possible undersupply of electricity and heat are compared with losses caused by the operation of equipment with reduced efficiency. Express tests also determine the time during which operation of equipment with reduced efficiency is allowed.
In general, equipment maintenance and repair involve the implementation of a set of works aimed at ensuring the good condition of the equipment, its reliable and economical operation, carried out with a certain frequency and consistency.
Repair cycle- the smallest repeating intervals of time or operating time of a product, during which all established types of repairs are carried out in a certain sequence in accordance with the requirements of regulatory and technical documentation (operating time of power equipment, expressed in years of calendar time between two planned overhauls, and for newly introduced equipment - operating time from commissioning to the first planned overhaul).
Repair cycle structure determines the sequence of various types of repairs and equipment maintenance work within one repair cycle.
All equipment repairs are divided (classified) into several types depending on the degree of preparedness, the volume of work performed and the method of performing repairs.
Unscheduled repairs- repairs carried out without prior appointment. Unscheduled repairs are carried out when equipment defects occur that lead to failures.
Scheduled repairs- repairs, which are carried out in accordance with the requirements of normative and technical documentation (NTD). Planned repairs of equipment are based on the study and analysis of the service life of parts and assemblies with the establishment of technically and economically sound standards.
Scheduled repairs of a steam turbine are divided into three main types: major, medium and current.
Major renovation- repairs performed to restore serviceability and restore full or close to full service life of equipment with the replacement or restoration of any of its parts, including basic ones.
Overhaul is the most voluminous and complex type of repair; during its implementation, all bearings and all cylinders are opened, the shaft line and the flow part of the turbine are disassembled. If a major overhaul is carried out in accordance with a standard technological process, then it is called standard overhaul. If major repairs are carried out by means other than standard ones, then such repairs are classified as specialized repairs with the name of the derivative type from a standard overhaul.
If major standard or major specialized repairs are performed on a steam turbine that has been in operation for more than 50 thousand hours, then such repairs are divided into three categories of complexity; the most complex repairs are in the third category. Categorization of repairs is usually applied to turbines of power units with a capacity of 150 to 800 MW.
Categorizing repairs by degree of complexity is aimed at compensating for labor and financial costs due to wear and tear of turbine parts and the formation of new defects in them, along with those that appear during each repair.
Maintenance- repairs performed to ensure or restore the operability of equipment, and consisting of replacement and (or) restoration individual parts.
Current repairs of a steam turbine are the least voluminous; when performing it, bearings may be opened or one or two control valves may be disassembled, and the automatic shutter valve may be opened. For block turbines, current repairs are divided into two categories of complexity: first and second (the most complex repairs have the second category).
Medium renovation- repairs carried out to the extent established in the technical documentation to restore serviceability and partially restore the service life of equipment with the replacement or restoration of individual components and monitoring their technical condition.
The average repair of a steam turbine differs from capital and current repairs in that its range partially includes the volumes of both capital and current repairs. When performing a medium repair, one of the turbine cylinders may be opened and the shaft line of the turbine unit may be partially disassembled; the stop valve may also be opened and partial repairs of the control valves and flow parts of the opened cylinder may be performed.
All types of repairs have the following characteristics in common: cyclicality, duration, volumes, financial costs.
Cyclicality- this is the frequency of carrying out one or another type of repair on a scale of years, for example, no more than 5...6 years should pass between the next and previous major repairs, no more than 3 years should pass between the next and previous medium repairs, between the next and previous current repairs no more than 2 years should pass. Increasing the cycle time between repairs is desirable, but in some cases this leads to a significant increase in the number of defects.
Duration repairs for each main type based on standard work is directive and approved by the “Rules for organizing maintenance and repair of equipment, buildings and structures of power plants and networks”. The duration of repairs is determined as a value on the scale of calendar days, for example, for steam turbines, depending on the power, a typical overhaul ranges from 35 to 90 days, an average from 18 to 36 days, an ongoing one from 8 to 12 days.
Important issues are the duration of repairs and its financing. The duration of turbine repair is a serious problem, especially when the expected volume of work is not confirmed by the condition of the turbine or when additional work arises, the duration of which can reach 30...50% of the target.
Volume of work are also defined as a standard set of technological operations, the total duration of which corresponds to the directive duration of the type of repair; in the Rules this is called “the nomenclature and scope of work during a major (or other type) repair of a turbine” and then there is a list of the names of the work and the elements to which they are aimed.
Derivative names of repairs from all main types of repairs differ in the volume and duration of work. The most unpredictable in terms of volume and timing are emergency repairs; they are characterized by such factors as the suddenness of an emergency shutdown, the unavailability of material, technical and labor resources for repairs, the uncertainty of the reasons for the failure and the volume of defects that caused the shutdown of the turbine unit.
When performing repair work, various methods can be used, including:
aggregate repair method- an impersonal repair method, in which faulty units are replaced with new or pre-repaired ones;
factory repair method- repair of transportable equipment or its individual components at repair plants based on the use of advanced technologies and developed specialization.
Equipment repair is carried out in accordance with the requirements of regulatory, technical and technological documentation, which include current industry standards, technical specifications for repairs, repair manuals, operating instructions, guidelines, norms, rules, instructions, performance characteristics, repair drawings and more.
At the present stage of development of the electric power industry, characterized by low rates of renewal of fixed production assets, the priority of equipment repair and the need to develop a new approach to financing repairs and technical re-equipment are increasing.
The reduction in the use of installed capacity of power plants has led to additional wear and tear on equipment and an increase in the share of the repair component in the cost of generated energy. The problem of maintaining the efficiency of energy supply has increased, in the solution of which the leading role belongs to the repair industry.
The existing energy repair production, previously based on scheduled preventive maintenance with regulation of repair cycles, has ceased to meet economic interests. The previously existing PPR system was formed to carry out repairs in conditions of a minimum reserve of energy capacity. Currently, there has been a decrease in the annual operating time of equipment and an increase in the duration of its downtime.
In order to reform the current maintenance and repair system, it was proposed to change the maintenance and repair system and switch to a repair cycle with an assigned time between repairs by type of equipment. The new maintenance and repair system (STOIR) allows you to increase the calendar duration of the overhaul campaign and reduce average annual repair costs. According to the new system assigned overhaul life between major overhauls is taken to be equal to the base value of the total operating time for the repair cycle in the base period and is the standard.
Taking into account the current regulations at power plants, standards for time between repairs have been developed for the main equipment of power plants. The change in the PPR system is due to changed operating conditions.
Both equipment maintenance systems provide for three types of repairs: major, medium and current. These three types of repairs constitute a unified maintenance system aimed at maintaining equipment in working condition, ensuring its reliability and the required efficiency. The duration of equipment downtime for all types of repairs is strictly regulated. The issue of increasing the duration of equipment downtime for repairs when it is necessary to perform above-standard work is considered individually each time.
In many countries, a “condition-based” repair system for power equipment is used, which can significantly reduce the cost of repair maintenance. But this system involves the use of techniques and hardware that make it possible to monitor the current technical condition equipment.
Various organizations in the USSR, and later in Russia, developed systems for monitoring and diagnosing the condition of individual turbine components, and attempts were made to create complex diagnostic systems on powerful turbine units. These works require significant financial costs, but, based on the experience of operating similar systems abroad, they quickly pay off.
1.2. SCOPE AND SEQUENCE OF OPERATIONS DURING REPAIR
The administrative documents define the nomenclature and standard volumes of repair work for each type of main equipment of thermal power plants.
So, for example, when performing a major overhaul of a turbine, the following is carried out:
Inspection and defect detection of cylinder bodies, nozzle devices, diaphragms and diaphragm cages, seal cages, end seal housings, end and diaphragm seals, devices for heating flanges and housing studs, rotor blades and tires, impeller disks, shaft journals, support and thrust bearings , support housings, oil seals, rotor coupling halves, etc.
Elimination of detected defects.
Repair of cylinder body parts, including inspection of the metal of cylinder bodies, replacement of diaphragms if necessary, scraping of the planes of horizontal connectors of cylinder bodies and diaphragms, ensuring alignment of the flow part parts and end seals and ensuring clearances in the flow part in accordance with the standards.
Repair of rotors, including checking the deflection of the rotors, if necessary, replacing the wire bands or the stage as a whole, grinding the journals and thrust discs, dynamic balancing of the rotors and correcting the alignment of the rotor on the coupling halves.
Repair of bearings, including, if necessary, replacement of thrust bearing pads, replacement or refilling of support bearing shells, replacement of sealing ridges of oil seals, scraping of the horizontal parting plane of cylinder bodies.
Repair of couplings, including checking and correcting breaks and displacement of axes when mating coupling halves (pendulum and elbow), scraping the ends of coupling halves, and machining holes for connecting bolts.
Testing and characterization of the control system (SAR), defect detection and repair of control and protection units, and adjustment of the ACS before starting the turbine are carried out. Also, defect detection and elimination of oil system defects are carried out: cleaning of oil tanks, filters and oil lines, oil coolers, as well as checking the density of the oil system.
1.3. FEATURES OF ORGANIZING EQUIPMENT REPAIR AT TPP AND ENERGY REPAIR ENTERPRISE
Repair of TPP equipment is carried out by TPP specialists (economic method), specialized energy repair units of the energy association (system economic method) or third-party specialized energy repair enterprises (ERP). In table 1.1 shows, as an example, data for 2000 (from the official website of RAO UES of Russia) on the distribution of the volume of repair work between its own repair personnel and contractors for the energy systems of the Ural region.
Table 1.1
The ratio of repair work performed by in-house and outsourced repair personnel in some energy systems of the Urals
The organization of repair maintenance at thermal power plants is carried out by the director, chief engineer, heads of workshops and departments, senior foremen, simply foremen, engineers of departments and laboratories. In Fig. 1.1, one of the possible repair management schemes is shown only in the scope of repair of individual parts of the main equipment, in contrast to the actual scheme, which also includes the organization of equipment operation. All heads of main departments, as a rule, have two deputies: one deputy for operation, the other for repair. The director makes decisions on financial issues of repair, and the chief engineer makes decisions on technical issues, receiving information from his deputy for repairs and from shop managers.
For thermal power plants whose main task is energy production, it is not economically feasible to carry out full maintenance and repair of equipment on our own. It is most advisable to involve specialized organizations (sites) for this purpose.
Repair maintenance of equipment in boiler-turbine shops at thermal power plants is carried out, as a rule, by a centralized repair shop (CR), which is a specialized unit capable of repairing equipment to the required extent. CCR has material and technical means, including: warehouses for property and spare parts, office offices equipped with communications equipment, workshops, mechanical repair area (RMS), lifting mechanisms, welding equipment. CCR can partially or completely repair boilers, pumps, elements of the regeneration system and vacuum system, chemical shop equipment, fittings, pipelines, electric drives, gas components, machine tools, and vehicles. CCR is also involved in repairing the network water recycling system and servicing repairs of coastal pumping stations.
From the one shown in Fig. 1.2 of the approximate diagram of the organization of the central control center, it is clear that repairs in the turbine room are also divided into separate operations, the implementation of which is carried out by specialized units, groups and teams: “flow specialists” - repair cylinders and the flow part of the turbine, “controllers” - repair components of the automatic control system and steam distribution; oil repair specialists repair the oil tank and oil lines, filters, oil coolers and oil pumps, “generator technicians” repair the generator and exciter.
Repair of power equipment is a whole complex of paraseparate and intersecting works, therefore, when repairing it, all divisions, units,groups and teams interact with each other. For precise implementation of the complex of operationswalkie-talkies, organizing interaction between individual repair departments, determiningThe terms of financing and delivery of spare parts before the start of repairs are being developedschedule for its implementation. Typically, a network model of the equipment repair schedule is developed (Fig. 1.3). This model determines the sequence of work and the possible start and end dates of the main repair operations. For convenient use in repairs, the network model is performed on a daily scale (the principles of constructing network models are presented in Section 1.5).
The power plants’ own repair personnel perform equipment maintenance, part of the volume of repair work during scheduled repairs, and emergency restoration work; specialized repair enterprises, as a rule, are hired to carry out major and medium repairs of equipment, as well as its modernization.
More than 30 ERPs have been created in Russia, the largest of which are Lenenergoremont, Mos-Energoremont, Rostovenergoremont, Sibenergoremont, Uralenergoremont and others. The organizational structure of an energy repair enterprise (using the example of the structure of Uralenergoremont, Fig. 1.4) consists of management and workshops, the name of the workshops indicates the type of their activity.
Rice. 1.2. Approximate diagram of the organization of the center
For example, a boiler shop repairs boilers, an electrical shop repairs transformers and batteries, regulation and automation shop - repair of SART steam turbines and steam boiler automation systems, generator shop repairs electric generators and engines, turbine shop repairs the flow part of turbines. A modern ERP, as a rule, has its own production base, equipped with mechanical equipment, cranes, and vehicles.
Turbine repair shop usually ranks second in the ERP in terms of number of personnel after the boiler shop; it also consists of a management team and production areas. In the workshop management group there is a chief and two of his deputies, one of whom is responsible for organizing repairs, and the other for preparing for repairs. The turbine repair shop (turbine shop) has a number of production areas. Typically, these sites are based at thermal power plants within their service region. A section of a turbine repair shop at a thermal power plant, as a rule, consists of a work manager, a group of subordinate foremen and senior foremen, as well as a team of workers (mechanics, welders, turners). When a turbine overhaul begins at a thermal power plant, the head of the turbine repair shop sends a group of specialists there to carry out repair work, who must act together with the personnel of the site at the thermal power plant. In this case, as a rule, a specialist from the traveling engineering staff is appointed as the repair manager.
When a major overhaul of equipment is carried out at a thermal power plant where there is no ERP production area, traveling (line) workshop personnel with a management specialist are sent there. If there are not enough traveling personnel to perform a specific volume of repairs, workers from other permanent production sites based at other thermal power plants (as a rule, from their region) are involved.
The management of the TPP and the ERP agree on all repair issues, including the appointment of an equipment repair manager (usually he is appointed from among the specialists of the general contracting (general) organization, i.e. the ERP).
As a rule, an experienced specialist in the position of senior foreman or leading engineer is appointed as the repair manager. Only experienced specialists in a position not lower than a foreman are also appointed as managers of repair operations. If young specialists are involved in repairs, then by order of the workshop manager they are appointed as assistants to specialist mentors, i.e., foremen and senior foremen who supervise key repair operations.
As a rule, the TPP’s own personnel and several contractors participate in the overhaul of equipment, therefore a repair manager is appointed from the TPP, who resolves issues of interaction between all contractors; under his leadership, daily ongoing meetings are held, and once a week meetings are held with the chief engineer of the thermal power plant (the person personally responsible for the condition of the equipment in accordance with the current RD). If failures occur during repairs that lead to disruption of the normal progress of work, shop managers and chief engineers of contracting organizations take part in the meetings.
1.4. PREPARATION FOR EQUIPMENT REPAIR
At TPPs, preparation for repairs is carried out by specialists from the preparation and repair department (PPPR) and the centralized repair shop. Their tasks include: planning repairs, collecting and analyzing information on new developments of measures to improve the reliability and efficiency of equipment, timely distribution of orders for spare parts and materials, organizing the delivery and storage of spare parts and materials, preparing documentation for repairs, providing training and retraining of specialists, carrying out inspections to assess the operation of equipment and ensure safety precautions during repairs.
During the periods between repairs, the Center is engaged in routine maintenance of equipment, training of its specialists, replenishing its resources with materials and tools, and repairs machines, lifting mechanisms and other repair equipment.
The equipment repair schedule is coordinated with higher-level organizations (power system management, dispatch control).
One of the most important tasks in preparing for repairs of thermal power plant equipment is the preparation and implementation of a comprehensive repair preparation schedule. A comprehensive preparation schedule for repairs should be developed for a period of at least 5 years. A comprehensive plan usually includes the following sections: development of design documentation, production and acquisition of repair equipment, training of specialists, construction volumes, repair of equipment, repair of machine tools, repair of vehicles, social and domestic issues.
A long-term comprehensive plan for preparation for repairs is a document that defines the main direction of activity of the repair departments of thermal power plants to improve repair services and prepare for repairs. When preparing the plan, the availability of funds at the thermal power plant necessary to carry out repairs is determined, as well as the need for the acquisition of tools, technologies, materials, etc.
A distinction must be made between repair tools and repair resources.
Repair tools- this is a set of products, devices and various equipment, as well as various materials, with the help of which repairs are carried out; These include:
standard tools manufactured by machine-building enterprises or firms and purchased by repair enterprises in the amount of annual needs (keys, drills, cutters, hammers, sledgehammers, etc.);
standard pneumatic and electric tools manufactured by factories such as Pnevmostroymash and Elektromash;
standard metalworking machines manufactured by machine-building plants in Russia and foreign countries;
devices manufactured by machine-building plants under contracts with repair companies;
devices designed and manufactured by repair companies themselves under agreements with each other;
devices manufactured by factories and supplied to installation sites along with the main equipment.
Under repair resources one should understand the totality of means that determine “how to do repairs”; these include information:
about the design features of the equipment;
repair technologies;
design and technical capabilities of repair equipment;
in the order of development and execution of financial and technical documents;
rules for organizing repairs at thermal power plants and internal regulations of the customer;
safety regulations;
rules for preparing time sheets and documents for write-off of products and materials;
features of working with repair personnel during the preparation and conduct of a repair company.
1.5. BASIC PROVISIONS FOR PLANNING REPAIR WORK
When carrying out repairs of thermal power plant equipment, the following main features are characteristic:
The dynamism of repair work, manifested in the need for a high pace, the involvement of a significant number of repair personnel on a wide front in parallel work, the continuous receipt of information about newly identified equipment defects and changes in volumes (repair work is characterized by the probabilistic nature of the planned volume of work and strict certainty of the timing of the entire set of works).
Numerous technological connections and dependencies between various jobs for the repair of individual units within the equipment being repaired, as well as between the units of each unit.
Non-standard nature of many repair processes (each repair differs from the previous one in its scope and conditions of work).
Various limitations in material and human resources. During the period of work, quite often it is necessary to divert personnel and material resources for the urgent needs of existing production.
Tight deadlines for completing repair work.
Process Modeling overhaul allows you to simulate the process of equipment repair, obtain and analyze relevant indicators and, on this basis, make decisions aimed at optimizing the volume and timing of work.
Linear model- this is a sequential (and parallel, if the work is independent) set of all works, which allows you to determine the duration of the entire complex of work by horizontal calculation, and by vertical calculation - the calendar requirement for personnel, equipment and materials. The resulting linear graph (Fig. 1.5) is a graphical model of the problem being solved and belongs to the group of analog models. The linear modeling method is used when repairing relatively simple equipment or when performing small amounts of work (for example, current repairs) on complex equipment.
Linear models are not able to reflect the basic properties of the modeled repair system, since they lack connections that determine the dependence of one job on another. In the event of any change in the situation during the work, the linear model ceases to reflect the real course of events and it is impossible to make significant changes to it. In this case, the linear model must be built anew. Linear models cannot be used as a management tool in the production of complex work packages.
Rice. 1.5. Example of a line graph
Network model- this is a special type of operating model that provides, with any necessary precision of detail, a display of the composition and relationship of the entire complex of works over time. The network model is amenable to mathematical analysis, allows you to determine a real calendar plan, solve problems of rational use of resources, evaluate the effectiveness of managers' decisions even before they are transferred for execution, evaluate the actual state of a set of works, predict the future state, and timely detect bottlenecks.
The components of a network model are a network diagram, which is a graphical representation technological process repairs, and information about the progress of repair work.
The main elements of a network diagram are the works (segments) and events (circles).
There are three types of work:
actual work- work that requires time and resources (labor, material, energy and others);
expectation- a process that requires only time;
fictitious work- dependence that does not require the expenditure of time and resources; fictitious work is used to depict objectively existing technological dependencies between jobs.
Dummy work is indicated by a dotted arrow.
Event in the network model is the result of performing a specific job. For example, if we consider “scaffolding” as a work, then the result of this work will be the event “scaffolding is completed”. An event can be simple or complex, depending on the results of completing one, two or more incoming activities, and can also not only reflect the facts of completion of the activities included in it, but also determine the possibility of starting one or more outgoing activities.
An event, unlike work, does not have a duration; its characteristic is the time of occurrence.
By location and the roles in the event network model are divided into the following:
original event the completion of which means the possibility of starting a set of works; it has none incoming work;
final event the completion of which means the completion of a set of works; it has none coming out work;
intermediate event the completion of which means the completion of all work included in it and the possibility of beginning the execution of all outgoing work.
Network models that have one terminating event are called single-purpose.
The main feature of a complex of repair work is the presence of a system for performing work. In this regard, there is a concept precedence and immediate precedence. If the jobs are not interconnected by a precedence condition, then they are independent (parallel), therefore When depicting the repair process in network models, only work connected by a precedence condition can be depicted sequentially (in a chain).
The primary information about the repair work of the network model is the amount of work expressed in natural units. Based on the volume of work, based on the standards, the labor intensity of the work can be determined in man-hours (man-hours), and knowing the optimal composition of the unit, the duration of the work can be determined.
Basic rules for constructing a network diagram
The graphics must clearly show technological sequence performance of work.
Examples of displaying such a sequence are given below.
Example 2. After completing the work “laying the hose hose in the cylinder” and “laying the hose in the cylinder”, you can begin the work “aligning the rotors” - this relationship is shown below:
Example 1. After “stopping and cooling the turbine”, you can begin to “disassemble the insulation” of the cylinders - this relationship is depicted as follows:
Example 3. To start the work “opening the HPC cover”, it is necessary to complete the work “disassembling the fasteners of the horizontal HPC connector” and “disassembling the RVD-RSD coupling”, and to “check the alignment of the RVD-RSD”, it is sufficient to complete the work “disassembling the RVD-RSD coupling” - this dependence is shown below:
There should be no cycles in power equipment repair network schedules, since cycles indicate a distortion of the relationship between works, since each of these works turns out to be prior to itself. An example of such a loop is given below:
Network diagrams should not contain errors like:
dead ends of the first kind- the presence of events that are not initial and do not have incoming work:
dead ends of the second kind- the presence of events that are not final and do not have outgoing work:
All network schedule events must be numbered. The following requirements apply to event numbering:
Numbering must be done sequentially, using natural numbers, starting from one;
The number of the ending event of each job must be greater than the number of the starting event; fulfillment of this requirement is achieved by the fact that an event is assigned a number only after the initial events of all activities included in it are numbered; 
In a network diagram, each event can be depicted only once. Each number can be assigned to only one specific event. Likewise, each work in the network diagram can only be depicted once, and each code can be assigned to only one work. If, for technological reasons, two or more jobs have common start and end events, then in order to exclude the same designation of jobs, an additional event and a fictitious job are introduced:
Building repair network models is a rather labor-intensive task, so in recent years a number of works have been carried out to create computer programs, intended for constructing network diagrams.
1.6. BASIC DOCUMENTS USED IN THE PROCESS OF PREPARATION AND CARRYING OUT EQUIPMENT REPAIR
When preparing and carrying out repairs of power equipment, it is used a large number of various documents, including: administrative, financial, economic, design, technological, repair, safety documents and others.
Before starting repairs, it is necessary to prepare the appropriate administrative and financial documents: orders, contracts, acts on the readiness of equipment for repair, a list of equipment defects, a statement of the scope of work, estimates for the work, certificates of inspection of lifting mechanisms.
If a contractor is hired to carry out repairs, it prepares a contract for repairs and an estimate of the cost of repair work. The drawn up contract determines the status of the contractor, the cost of repair work, responsibilities parties regarding order maintenance of seconded personnel and the procedure for mutual settlements. The compiled estimate lists all the work related to repairs, their names, quantities, prices, and indicates all coefficients and additions related to the price rate for the period of concluding the repair contract. To estimate the cost of work, as a rule, price lists and reference books, time standards, statements of volume of work, tariff guides. For certain types of work, a special calculation is prepared; in case of determining the cost of work by calculation, reference books of time standards for these types of work are used.
After the contract and estimate are signed by the customer and the contractor, all subsequent documents determining the financial support for repairs come into force, including (in aggregate):
statements for the purchase of tools;
statements for the purchase of materials and spare parts;
statements for the issuance of overalls, soap, mittens;
statements for the issuance of travel allowances (daily allowance, hotel payment, transport payment, etc.);
waybills for the transportation of repair equipment;
powers of attorney for material assets;
payment requirements.
Technical conditions for repairs- a regulatory and technical document containing technical requirements, indicators and standards that a specific product must satisfy after a major overhaul.
Overhaul Manual- a regulatory and technical document containing instructions on the organization and technology of repairs, technical requirements, indicators and standards that a specific product must satisfy after a major overhaul.
Repair drawings- drawings intended for repair of parts, assembly units, assembly and control of a repaired product, production of additional parts and parts with repair dimensions.
Measurement map- technological control document intended for recording the results of measurement of controlled parameters indicating the signatures of the performer of the operation, the work manager and the supervisor.
In addition, the archive contains equipment drawings, a set of documents on the technological process of equipment repair, and technological instructions for individual special repair operations.
At thermal power plants, documentation on previously performed equipment repairs should also be stored in the archive. These documents are compiled according to station equipment numbers; they are kept in the repair preparation department, partly by the head of the turbine shop, and also by the head of the central control center. Completing and storing these documents allows you to constantly accumulate information about repairs, which serves as a kind of “medical history” of the equipment.
Before starting equipment repairs in the ERP workshop, a list of workers and persons responsible for the work is developed; an order appointing a repair manager and a list of workers indicating their positions and qualifications are issued and approved.
The appointed repair manager draws up a list of documents necessary for the work. It necessarily contains: financial forms (estimates, acts of form No. 2, additional agreements, time sheets), working time recording forms, linear chart forms, barn books for keeping logs (technical and shift assignments), lists of persons responsible for work orders -tolerances, and forms for write-off of materials and tools.
During repairs, it is necessary to document the condition of the main equipment and its parts, draw up protocols on the control of metal equipment and spare parts, revise the repair schedule if it is necessary to clarify the condition of the equipment, draw up technical solutions on repairs to eliminate equipment defects using non-standard methods.
During the repair process, the repair manager develops and prepares the following basic documents:
a report on defects identified during inspection of equipment elements during disassembly (second assessment of the condition of the equipment);
an act to justify changes in the target repair period depending on the identified defects;
minutes of meetings on the most important repair issues, for example: shoveling steps, reinstalling supports, replacing a rotor, etc.;
updated work schedule due to changes in the scope of work;
financial documents: additional agreement to the contract and additional estimate, current acceptance certificates for work performed;
applications for new spare parts and components for the customer: blades, disks, cages, diaphragms, etc.;
acts of unit-by-unit acceptance of equipment from repair;
technical solutions for non-standard work using non-standard technology;
In addition, the manager organizes the keeping of logs: the issuance of tasks, technical records, safety briefings in the workplace, the availability of tools, devices and materials, work time sheets, statements for the issuance of mittens, napkins and others.
Upon completion of the repair, also under the guidance of ERP and TPP specialists, the following are developed and executed:
acceptance certificates for repair of main equipment components;
cylinder closure protocols;
protocol for handing over the oil tank for cleanliness;
forms for equipment assembly;
protocols for the density of the vacuum system;
hydraulic test reports;
act of testing the generator and its seals;
statement of basic parameters and technical condition;
act for balancing the shaft line of a turbine unit;
linear work completion schedules;
collection of forms and reporting documents;
acts for writing off spare parts and materials used for repairs.
1.7. BASIC METAL CONTROL METHODS USED IN TURBINE REPAIRS
During the repair of turbine units, a large amount of metal testing work is carried out, using a combination of various physical non-destructive testing methods. When used, no residual changes are created in the product being tested. These methods detect cracks, internal cavities, areas of looseness, lack of penetration in welds and similar violations of the continuity and homogeneity of materials. The most common methods are: visual inspection, ultrasonic flaw detection, magnetic particle flaw detection, and eddy current testing.
Magnetic particle flaw detection method is based on the fact that particles of a ferromagnetic substance placed on a magnetized surface accumulate in a zone of inhomogeneity of the medium.
When carrying out flaw detection, the surface of a magnetized product is sprinkled with dry ferromagnetic powder (fine filings of cast iron or steel) or poured with a liquid in which the fine ferromagnetic powder is suspended ("magnetic suspension"); Moreover, in those places where the cracks reach the surface of the product (although invisible due to their small opening) or come quite close to it, the powder accumulates especially intensively, forming easily noticeable ridges corresponding to the shape of the crack.
When applied to parts made of ferromagnetic materials, the method is highly sensitive and allows one to detect various defects on the surface of the part.
Ultrasonic flaw detection method is based on the ability of the energy of ultrasonic vibrations to propagate with low losses in a homogeneous elastic medium and to be reflected from discontinuities in this medium.
There are two main methods of ultrasonic testing - the through sound method and the reflection method. When carrying out flaw detection, an ultrasonic beam is introduced into the sample and the indicator measures the intensity of vibrations passing through the sample or reflected from inhomogeneities located inside the sample. A defect is determined either by a decrease in the energy transmitted through the sample, or by the energy reflected from the defect.
The advantages of ultrasonic testing include:
high sensitivity to detect small defects;
high penetrating power, allowing control of large-sized products;
the ability to determine the coordinates and dimensions of the defect.
Eddy current testing method (eddy current method) is based on the fact that eddy currents are induced in the test sample placed in an alternating magnetic field.
When testing metal, an alternating magnetic field is created using electromagnetic coils of various shapes (in the form of a probe, in the form of a fork, and others). In the absence of the test object, an empty test coil has a characteristic impedance. If the test object is placed in the electromagnetic field of the coil, it will change under the influence of the eddy current field. If there are inhomogeneities in the sample material, this will affect the change magnetic field coils. This method can determine the presence of cracks, their depth and size.
When repairing turbines, in addition to the methods described above, in some cases X-ray flaw detection, fluorescent flaw detection and other methods are also used.
1.8. TOOLS USED IN REPAIR WORK
To carry out equipment repairs, a large number of mechanical and measuring tools, as well as special devices, are used. Availability and quality the necessary tool determines labor productivity during repairs. Lack of tools causes frequent downtime.
A set of plumbing, mechanical and universal tools, which is necessary when repairing turbines, includes:
cutting tool- cutters, drills, taps, dies, reamers, countersinks, files, triangular, semicircular and flat scrapers, hacksaws and so on.;
impact-cutting- chisels, crosspieces, center punches and others;
abrasive- grinding wheels, skins;
mounting- screwdrivers, wrenches, socket wrenches, box and sliding wrenches, collars, wire cutters, pliers, steel, lead and copper sledgehammers, metalwork hammers, lead hammers, copper drifts, bits, scribers, steel brushes, bench vices, clamps.
When repairing a turbine, work is performed that requires measurements with high accuracy (up to 0.01 mm). Such accuracy is necessary when determining the degree of wear of parts, when measuring radial and end clearances using centering devices, checking clearances in keyed joints, as well as when assembling the turbine and its components.
For measuring linear dimensions or gaps plate and wedge probes, thread gauges, templates, gauges, test prisms, calipers, micrometers are used. Micrometers are also used to measure the external dimensions of parts.
To measure the internal dimensions of parts or distances between planes, accurately measuring the diameters of bores in turbine cylinders, and also to determine the size of keyways, a micrometric bore gauge is used.
When checking the flatness of surfaces Test plates of different sizes are used, for example 300x300 and 500x500.
For measuring slopes When installing foundation frames, aligning cylinders and bearing housings in the longitudinal and transverse directions, as well as measuring slopes on the rotor journals, use a “Geological exploration” type level or electronic levels.
To measure the heights of parts A hydrostatic level with micrometer heads is used.
To measure load values Dynamometers are used on the supports of bearing housings and turbine cylinders.
For measuring beats shaft, thrust disc, end and radial surfaces of the couplings, dial indicators are used. In addition, they are convenient for measuring the linear movements of parts: the run-up of the rotor in the thrust bearing, the stroke of the control valves, and so on.
To mechanize the production of labor-intensive work, universal and specialized tools with pneumatic and electric drives are used:
pneumatic impact wrenches for loosening and bolting cylinders and bearing caps;
electrically driven devices for rotating rotors at low speeds, used for grinding rotor journals, grooving blade bands after shoveling, grooving the ridges of labyrinth seals, and so on;
electric grinders for cutting bandage wire during reblading and drilling blade rivets in disks;
mechanical reamer with electric drive and special self-tightening reamer for reaming holes for blade rivets;
portable radial drilling machines for drilling and cutting holes;
hand-held portable grinders with flexible drive rollers of steel cutters or abrasive wheels for filing flat surfaces;
pneumatic grinders, electric scrapers and hand scrapers with removable plates for scraping horizontal cylinder connectors, grinding discs and diaphragms.
To carry out a number of repair works, an electric welding machine and a gas cutting unit are used.
Flamethrowers are used to heat parts during the operation of attaching and removing them.
When performing work, production tools and technological equipment are used. The set of production tools necessary to carry out a technological process is called means of technological equipment.
Technological equipment- technological equipment that complements technological equipment to perform a certain part of the technological process. An example of technological equipment is: cutting tools, fixtures, gauges, etc.
1.9. SELF-TEST QUESTIONS
What is the purpose of organizing a system for maintenance and repair of thermal power plant equipment?
What is a PPR system?
Define the terms "maintenance" and "repair".
List the main indicators of operational monitoring of the technical and economic condition of the turbine flow path.
What are rapid tests? How are they carried out?
Define the terms “repair cycle” and “repair cycle structure”.
What is the fundamental difference between unplanned and scheduled repairs turbines?
What are the main differences in types of repairs between major, medium and current.
What and how are the volume and duration of repairs determined?
What repair methods do you know?
Who are the managers and responsible persons during the repair of turbines at thermal power plants?
Who at the thermal power plant prepares for repairs?
What is the purpose of modeling the repair process? What is a linear model of the repair process?
What is a network model? Explain the term “network diagram as an integral part of a network model.”
List the main elements and basic rules for constructing a network repair schedule.
List the main documents that must be completed before repairs begin.
What documents and by whom are drawn up upon completion of repairs?
List and classification of tools used in turbine repair. What is technological equipment?
Must be organized in strict accordance with the requirements of the manufacturer's instructions, technical operation rules, fire safety and safety precautions when servicing thermal mechanical equipment power stations and networks, trained for this work by specialists.
At each power plant, in accordance with the above materials, local instructions for the operation of turbines are developed, outlining the rules for starting, stopping, shutting down, possible problems with the equipment of the turbine unit and the procedure for their prevention and elimination, which are mandatory for operating personnel.
Problems preventing the turbine from starting.
Despite the differences in turbine designs, circuits, auxiliary equipment, there is a common one for
all list of defects and malfunctions that must be eliminated before start-up.
Starting the turbine is prohibited:
- in the absence or malfunction of the main devices that control the flow thermal process in the turbine and its mechanical condition (pressure gauges, thermometers, vibration meters, tachometers, etc.);
- if it is faulty, i.e. the oil tank must be inspected (oil level, indicator
level), oil coolers, oil lines, etc.;
- if there is a fault in all circuits, stopping the supply of steam to the turbine. The entire protection chain from sensors to actuators is checked (axial shift relay, vacuum relay, safety circuit breaker, atmospheric valves, stop and control valves, shut-off valves on steam pipelines of fresh steam, extractions);
- if faulty;
- if the turning device is faulty. Applying steam to a stationary rotor can cause it to bend.
Preparing to start the turbine.
The technology for starting a turbine depends on its temperature state. If the metal temperature of the turbine (HPC housing) is below 150 °C, then it is considered that the start is made from a cold state. This takes at least three days after it stops.
Starting from a hot state corresponds to a turbine temperature of 400 °C and above.
At an intermediate temperature value, a cold start is considered.
The basic principle of the launch is to be carried out at the maximum speed possible in terms of reliability (do no harm).
The main feature of starting a non-unit turbine (TPP with cross connections) is the use of steam nominal parameters.
Starting a turbine consists of three stages: preparatory, a period of rotation with bringing the speed to full (3000 rpm) and synchronization (connection to the network) and subsequent loading.
During the preparatory period, the general condition of all equipment of the turbine installation, the absence of unfinished work, and the serviceability of instruments and alarms are checked. Warming up the steam pipeline and bypass pipes lasts 1-1.5 hours. At the same time, the water supply to the condenser is prepared. The operation of all oil pumps is checked (except for the hydraulic oil pump - on the turbine shaft), the starting oil pump is left in operation and the turning device is turned on. Protection and control systems are checked with the main steam valve (MSV) closed and no steam pressure in front of the stop valve. Vacuum build-up begins. the control mechanism is brought to the minimum position, the safety circuit breaker is armed, and the turbine housing drains are opened.
Turbine push.
The rotor is pushed (brought into rotation) either by opening the first control valve or by the gas treatment plant bypass with the control valves fully open.
The turbine is kept at low speeds (500-700), thermal expansion is checked, seals, housings, bearings are listened to with a stethoscope, instrument readings for oil, temperature, pressure, relative expansion.
The critical frequencies of the shaft line must be passed quickly and after inspecting all the elements of the turbine, and if there are no deviations from the norms, you can go for a turn, constantly listening to the turbine. In this case, the temperature difference between the top and bottom of the cylinder should not exceed 30-35 °C, and between the flange and the stud no more than 20-30 °C. When 3000 rpm is reached, the turbine is inspected, the protection and control systems are checked, and manual and remote shutdown of the turbine is tested. The control mechanism checks the smooth movement of the control valves, checks the operation of the safety circuit breaker by supplying oil to the strikers, and, if necessary (as required by the rules), by increasing the speed.
If there are no comments, the signal “Attention! Ready". After connecting the generator to the network, the turbine is loaded according to the instructions.
Starting turbines with back pressure.
Parameters are subject to special control, the deviation of which beyond acceptable limits threatens the reliable operation of the turbine - this is the relative elongation of the rotor and its axial displacement, the vibration state of the unit.
The parameters of fresh steam, after and inside the turbine, oil in the control and lubrication system are constantly monitored, preventing heating of the bearings, and the operation of the seals.
The operating instructions define vacuum, feed water temperature, cooling water heating, temperature pressure in the condenser and condensate subcooling, because The economical operation of the turbine depends on this. It has been established that deterioration in the operation of regenerative heaters and underheating of feed water by 1 °C leads to an increase in specific consumption heat by 0.01%.
The flow part of the turbine is subject to contamination by salts contained in the steam. Salt contamination, in addition to reducing efficiency, deteriorates the reliability of the blade apparatus and the turbine as a whole. To clean the flow part, wash with wet steam. But this is a very responsible, and therefore undesirable, operation.
Normal operation of a turbine is unthinkable without careful monitoring, maintenance and regular checks protection and control systems, therefore, a constant thorough inspection of control units and elements, protections, and steam distribution parts is necessary, paying attention to oil leaks, fasteners, and locking devices; move the stop and control valves.
According to the PTE, within the time frame, established by the instructions, the strikers of the safety machine must be regularly tested by pouring oil and increasing the turbine speed, checking the tightness of the locking, regulating and check valves. Moreover, it is necessary after installation, before and after major repairs. The stop and control valves may not be completely tight, but closing them together should prevent the rotor from rotating.
Turbine stop.
When stopping the turbine in hot reserve, it is desirable to keep the metal temperature as high as possible. A shutdown with cooling is carried out when the turbine is put into long-term reserve or for major and current repairs.
Before shutting down, at the direction of the station shift manager, according to the instructions, the turbine is unloaded with the controlled extraction and regeneration turned off.
Having reduced the load to 10-15% of the nominal load and received permission, pressing the shutdown button stops the supply of steam to the turbine. From this moment the turbine rotates electrical network, i.e. The generator operates in engine mode. To avoid heating of the tail part of the turbine, it is necessary to very quickly ensure that the stop, control and check valves on the extraction lines are closed, and the wattmeter indicates negative power, because The generator consumes power from the network during this period. After this, disconnect the generator from the network.
If, due to leakage of valves, their freezing, or for other reasons, steam enters the turbine and there is a load on the unit according to the wattmeter, then disconnecting the generator from the network is strictly prohibited, since the steam entering the turbine may be sufficient to accelerate it.
It is urgent to close the main steam valve (MSV), its bypass, tighten the valves at the extraction points, tap the valves, make sure that no steam enters the turbine, and only then disconnect the generator from the network.
When unloading the turbine, you need to carefully monitor the relative contraction of the rotor, not allowing it to reach dangerous limits.
After the turbine is switched to idle, all tests required according to the instructions are carried out. After disconnecting the turbogenerator from the network, the rotor begins to coast down, at which the rotation speed decreases from the nominal to zero. This rotation occurs due to the inertia of the shafting. It should be noted that the weight of the rotating parts of the T-175 turbine, together with the generator and exciter rotors, is 155 tons.
Rotor run-out is an important operational indicator that allows you to judge the condition of the unit.
Be sure to record the run-out curve - the dependence of the rotation speed on time. Depending on the power, the run-out is 20-40 minutes. If there is a deviation of 2-3 minutes, you need to look for the cause and eliminate it.
After the rotor stops, the shaft turning device (TDU) is immediately switched on, which must operate until the temperature of the turbine metal drops below 200 °C.
During the run-down process and after, all other operations regarding oil, circulating water, etc. are performed. according to instructions.
Turbine emergency shutdown.
If an emergency situation occurs at a turbine unit, it is necessary to act in accordance with the emergency instructions, which define a list of possible emergency situations and measures to eliminate them.
When eliminating an emergency situation, you need to carefully monitor the main indicators of turbine operation:
— rotation speed, load;
— fresh steam parameters and ;
— vacuum in the condenser;
— vibration of the turbine unit;
— axial displacement of the rotor and the position of the rotors relative to their housings;
— oil level in the oil tank and its pressure in the control and lubrication systems, oil temperature at the inlet and drainage from the bearings, etc.
The emergency instructions define methods of emergency shutdown depending on emergency circumstances - without vacuum failure and with vacuum failure, when atmospheric air is admitted into the exhaust of the turbine and condenser by opening the valve.
An emergency stop of the turbine unit is carried out by immediately stopping the supply of fresh steam to the turbine using the emergency stop button or remotely acting on the electromagnetic switch, and, making sure that the turbine is turned off and does not bear a load, send a signal to the main control room “Attention! The car is in danger! After which the generator is disconnected from the network. Be sure to close the main steam valve (MSV), its bypass and intake valves.
Further shutdown operations are carried out in the usual way.
The vacuum is broken when it is necessary to speed up the shutdown of the rotor, for example, with a sharp drop in the oil level, with water hammer in the turbine, with sudden strong vibration, with a sharp axial shift of the rotor, etc.
When stopping without breaking the vacuum, the rotor of the K-200-130 turbine stops in 32-35 minutes, and when stopping the vacuum in 15 minutes, but during this operation the exhaust pipe is heated due to a sharp increase in the density of the medium, which leads to braking of the rotor. Therefore, stopping the turbine with vacuum failure is carried out only in cases specified by the emergency instructions.
TPA maintenance can be divided into the following stages:
Preparing the turbine for operation and starting;
Maintenance during operation;
Withdrawal and drainage;
Monitoring the turbine during inactivity.
Preparing the turbine unit for operation
Preparing a steam turbine unit for warming up begins with checking the condition of the unit and servicing systems.
To do this you need to do the following:
Prepare turbines and gears, i.e.
inspect turbines and gears and make sure that all standard instrumentation is present and in good working order. Check the condition of the housing expansion indicators and sliding supports. Take measurements of the axial and radial position of the shafts and the axial position of the housings.
Prepare and commission the oil system.
To do this you need:
Remove settled water and sludge from oil tanks;
Check the oil level in waste and pressure gravity tanks; 0 In case of low oil temperature, heat it to 30...35 WITH , while ensuring that the heating steam pressure does not exceed 0.11...0.115;
MPa
Start the oil separator and put it into operation;
Prepare the filters and oil cooler for operation, open the corresponding valves and blades;
Prepare for start-up and start the oil pump;
Open the air valves on the filter, oil coolers on all turbine and gear bearing covers, release the air and check that the oil system is filled with oil;
Check the flow of oil to lubricate the gear teeth, if necessary, open the inspection hatches for this;
Make sure that the pressure in the lubrication and regulation systems corresponds to the values specified in the instructions;
Make sure there are no oil leaks from the system;
By lowering the oil level, check the serviceability of the warning device; After launch circulation pump
open the circulating water valves at the oil cooler, check the water circulation;
Check the operation of thermostats;
Make sure there is sufficient oil overflow from the pressure gravity tank.
Prepare the turning device for operation;
Inspect and prepare the shafting;
When preparing the shafting for rotation, you must:
Check that there are no foreign objects on the shaft line;
Release the shaft brake;
If necessary, loosen the stern tube seal;
Check and prepare the bearing cooling system for operation;
Prepare and turn on the turning device;
When turning on the shaft turning device, hang a sign at the control station: TURNING DEVICE ON. To test rotate the TPU turbine unit, it is necessary to obtain permission from the captain's watch officer. Turn the propeller forward and reverse by 1 and 1/3 turns. At the same time, use an ammeter to monitor the power consumed by the electric motor of the turning device and carefully listen to the turbine and gear train. Exceeding the load to the permissible value indicates a malfunction that must be eliminated.
Prepare the steam line and control system, alarm and protection;
Preparation consists of checking the operation of steam valves for opening and closing in the absence of steam in the steam lines:
Check whether the steam extraction valves from the turbines are closed;
Open the purge valves;
Open and close the quick-closing, shunting and nozzle valves to ensure that they operate properly;
Carry out an external inspection of pressure reducing and safety valves;
After supplying oil to the control system, turn off the vacuum relay, open the quick-closing valve, check its operation by turning it off by hand, lowering the oil pressure, and also by acting on the axial shift relay, then leave the valve closed and turn on the vacuum relay;
Open the purge valves of the receivers, quick-closing and shunting valves, the steam box and the chambers of the nozzle valve rods;
Before warming up the turbines, warm up and blow through the main steam line to the quick-closing valve through a special warm-up pipeline or by slowly opening the main isolation valves, gradually increasing the pressure in the steam line as it warms up.
Prepare the condensing system and the main condenser;
for this you need:
Open the inlet and outlet valves (or valves) of the circulation pump, start the main circulation pump;
Open the air taps on the water part of the main condenser, closing them after water flows out of them in a continuous stream;
Check and ensure that the condenser water side and circulation pump drain valves are closed;
Fill the main condenser condensate collector feed water up to half of the water meter glass;
Prepare for operation the automatic system for maintaining the condensate level in the condenser;
Check the opening of the valves on the condensate line supplied to the refrigerators (condensers) of the ejectors;
Open the valve on the return circulation pipeline;
Start up the condensate pump, then open the valve on its pressure pipe;
Check the operation of the condensate level regulator in the condenser.
Warm up the steam turbines.
Warming up of the turbines begins with the supply of steam to the end seals of the turbines, the main steam jet ejector is prepared and put into operation, thereby raising the vacuum in the condenser. Activate automatic pressure maintenance in the control system.
Raise the vacuum to full to check the density of the system and then reduce it to the value set by the manufacturer.
In the process of raising the vacuum, the turbine rotors are turned using a shaft turning device.
To warm up the turbines of the main turbo-gear units, three heating methods are used:
The first is heating the turbines when the rotor rotates with working steam while parked;
The second is heating the turbines when the rotors are rotated by a shaft turning device;
The third is combined, in which the heating is first carried out when the rotor is rotated by a shaft-turning device, and then, having received permission from the command bridge, test revolutions of the working steam of the turbines are given in forward motion. At the same time, turbines, gears and bearings are carefully listened to.
Check the steam pressure when starting the turbines, which should not exceed the values specified in the instructions. Change the direction of rotation of the turbines from forward to reverse using a shunting valve and again listen to all elements of the TPA. After the turbines are warmed up, the circulation condensate and oil pumps are switched to normal operating mode and the vacuum in the main condenser is raised to the operating value.
It should be borne in mind that turbine rotors can remain motionless after steam is supplied to the seals for no more than 5...7 minutes.
Check the blocking that prevents the unit from being started when the turning gear is turned on.
Carry out the process of test turning the valve.
When test turning turbo units using a shaft turning device, you must make sure that:
The quick-closing valve (QCV) is closed;
Turbine shunting valves are closed;
The automatic blocking of the turning device, if available, does not allow the UPC to be opened by oil pressure.
During the test rotation of the turbine unit using a shaft turning device, the following actions must be performed:
Rotate the turbine unit shafts, carefully listening to the turbines and gears;
Perform a test rotation of at least one revolution of the propeller shaft in forward and reverse;
Monitor the current strength consumed by the turning device and if the normal value is exceeded or there is a sharp fluctuation in the current, immediately stop the turning device until the causes are determined and the malfunctions are eliminated.
When turning the GTZA VPU, it is possible that the electric motor of the turning device has an increased load or sharp fluctuations when starting and turning the GTZA. This may happen for the following reasons:
It is possible that there may be contact inside the turbine in the blade or in the seal, or contact in the gear transmission while turning the GTZ, and a characteristic sound can be heard.
In this case, it is necessary to open the necks and listen from the inside, check the axial and radial clearances both in the flow part and in the bearings.
If unacceptable drawdowns or run-ups or defects in the turbine flow path are detected, open the housing or gearbox and eliminate the defects.
A sound characteristic of the presence of water can be heard in the turbine, water accumulation in the turbine housing, and overflow of the main condenser.
To eliminate them, it is necessary to open the turbine vent, remove water, and bring the level in the main condenser to normal.
Possible jamming inside the kinematic circuit of the VPU.
In this case, it is necessary to turn off the VPU, check the kinematic diagram and eliminate the jamming.
The motor may malfunction.
In this case, you need to check the bearings and electrical circuit and eliminate the malfunction.
The brake is stuck.
The cable is wound around the screw.
When warming up the turbines, the following procedures are prohibited:
Reduce the vacuum in the condenser by reducing the supply of steam to the seals;
Keep the UPC and shunting valves open when turning the GTZA with a turning device.
Once the turbines have warmed up, the following actions must be performed:
Carry out test runs of the turbine unit from all control stations;
Make sure the remote control system operates correctly.
During test revolutions of the GTZA, it is possible that the turbine does not start at the permissible value of steam pressure. This is possible for the following reasons:
Insufficient vacuum in the main condenser;
Thermal deflection of the turbine rotor as a result of local cooling during parking with a warm gas turbine unit and violation of the cranking mode.
In this case, the turbine installation should be taken out of operation and the turbine should be allowed to cool gradually. To ensure uniform cooling, it is necessary to close the inlet and outlet valves of the main condenser and remove the cooling water from it. After turning the GTZA VPU, put the installation into operation.
When the nozzle valves open, there is a pressure drop in the main steam line.
In this case, the valves on the main steam line may be faulty or may not be fully open.
