Electricity losses in electrical networks are the most important indicator of the efficiency of their operation, a clear indicator of the state of the electricity metering system, and the efficiency of energy sales activities of energy supply organizations. This indicator increasingly clearly indicates accumulating problems that require urgent solutions in the development, reconstruction and technical re-equipment of electrical networks, improvement of methods and means of their operation and management, increasing the accuracy of electricity metering, the efficiency of collecting funds for electricity supplied to consumers, etc. . According to international experts, the relative losses of electricity during its transmission and distribution in the electrical networks of most countries can be considered satisfactory if they do not exceed 4-5%. Electricity losses of 10% can be considered the maximum permissible from the point of view of the physics of electricity transmission through networks. It is becoming increasingly obvious that the sharp aggravation of the problem of reducing electricity losses in electrical networks requires an active search for new ways to solve it, new approaches to the selection of appropriate measures, and most importantly, to the organization of work to reduce losses.
Due to a sharp reduction in investments in the development and technical re-equipment of electrical networks, in the improvement of control systems for their modes, electricity metering, a number of negative trends have emerged that negatively affect the level of losses in networks, such as: outdated equipment, physical and moral wear and tear of electricity metering devices , inconsistency installed equipment transmitted power.
From the above it follows that against the backdrop of ongoing changes in the economic mechanism in the energy sector and the economic crisis in the country, the problem of reducing electricity losses in electrical networks not only has not lost its relevance, but, on the contrary, has become one of the tasks of ensuring the financial stability of energy supply organizations.
Some definitions:
Absolute losses of electricity are the difference in electricity supplied to the electrical network and usefully supplied to consumers.
Technical losses of electricity - losses caused by physical processes of transmission, distribution and transformation of electricity, are determined by calculation.
Technical losses are divided into conditionally constant and variable (depending on the load).
Commercial losses of electricity are losses defined as the difference between absolute and technical losses.
STRUCTURE OF COMMERCIAL ELECTRICITY LOSSES
Ideally, commercial losses of electricity in the electrical network should be zero. It is obvious, however, that in real conditions, supply to the network, useful supply and technical losses are determined with errors. The differences in these errors are actually the structural components of commercial losses. They should be minimized as much as possible by implementing appropriate measures. If this is not possible, it is necessary to make amendments to the electricity meter readings to compensate for systematic errors in electricity measurements.
Errors in measurements of electricity supplied to the network and usefully supplied to consumers.
The error in electricity measurements in the general case can be divided into many components. Let us consider the most significant components of the errors of measuring complexes (MC), which may include: current transformer (CT), voltage transformer (VT), electricity meter (EM), ESS connection line to TN.
The main components of measurement errors of electricity supplied to the network and usefully supplied electricity include:
errors in electricity measurements under normal conditions
IR work, determined by the accuracy classes of CT, VT and SE;
additional errors in electricity measurements in real operating conditions of the IR, due to:
underestimated load power factor compared to the standard (additional angular error); .
influence on solar cells of magnetic and electromagnetic fields of various frequencies;
underload and overload of CTs, HP and SE;
asymmetry and level of voltage supplied to the IR;
operation of solar power in unheated rooms with unacceptably low temperatures, etc.;
insufficient sensitivity of solar cells at low loads, especially at night;
systematic errors caused by excess service life of the IC.
errors associated with incorrect connection diagrams of electricity meters, CTs and VTs, in particular, phasing violations of meter connections;
errors caused by faulty electricity metering devices;
errors in reading electricity meters due to:
errors or intentional distortions in recordings of testimony;
non-simultaneity or failure to meet established deadlines for taking meter readings, violation of meter bypass schedules;
errors in determining the coefficients for converting meter readings into electricity.
It should be noted that with the same signs of the components of the measurement errors of supply to the network and useful supply, commercial losses will decrease, and if they are different, they will increase. This means that from the point of view of reducing commercial losses of electricity, it is necessary to pursue a coordinated technical policy to increase the accuracy of measurements of supply to the network and useful supply. In particular, if we, for example, unilaterally reduce the systematic negative measurement error (modernize the accounting system) without changing the measurement error, commercial losses will increase, which, by the way, occurs in practice.
Commercial losses caused by underestimation of useful supply due to shortcomings in energy sales activities.
These losses include two components: billing losses and losses from electricity theft.
Billing losses.
This commercial component is due to:
inaccuracy of data on electricity consumers, including insufficient or erroneous information on concluded contracts for the use of electricity;
errors in billing, including unbilled consumers due to the lack of accurate information on them and constant monitoring of the updating of this information;
lack of control and errors in billing to customers using special rates;
lack of control and accounting of adjusted accounts, etc.
Losses from electricity theft.
This is one of the most significant components of commercial losses, which is a matter of concern for energy workers in most countries of the world.
The experience of combating electricity theft in various countries is summarized by a special “Expert Group to study issues related to electricity theft and unpaid bills (non-payments)”. The group is organized within the framework of the research committee on economics and tariffs of the international organization UNIPEDE. According to a report prepared by this group in December 1998, the term "electricity theft" applies only when electricity is not accounted for or is not fully recorded due to the fault of the customer, or when the customer tampers with the meter or tampers with the electrical supply system in order to reduce the meter's metering. consumption of consumed electricity.
A generalization of international and domestic experience in combating electricity theft showed that these thefts are mainly carried out by household consumers. There are thefts of electricity carried out by industrial and commercial enterprises, but the volume of these thefts cannot be considered decisive.
Theft of electricity has a fairly clear upward trend, especially in regions with poor heat supply to consumers during the cold periods of the year. L also in almost all regions in the autumn-spring periods, when the air temperature has already dropped significantly, and the heating has not yet been turned on.
There are three main groups of methods of electricity theft: mechanical, electrical, magnetic.
Mechanical methods of electricity theft.
Mechanical methods of electricity theft.
Mechanical interference with the operation (mechanical opening) of the meter, which can take various forms, including:
drilling holes in the bottom of the case, cover or glass of the meter;
insertion (into the hole) of various objects such as 35 mm wide film, needles, etc. in order to stop the rotation of the disk or reset the counter;
moving the counter from a normal vertical to a semi-horizontal position in order to reduce the speed of rotation of the disk;
unauthorized breaking of seals, violation of the alignment of the axes of mechanisms (gears) to prevent complete recording of electricity consumption;
rolling out the glass when inserting a film that will stop the disc rotation.
Mechanical interference usually leaves a mark on the meter, but it is difficult to detect unless the meter is completely cleaned of dust and dirt and inspected by an experienced technician.
TO mechanical method Theft of electricity can be attributed to the quite widespread in Russia deliberate damage to solar cells by household consumers or theft of meters installed in the staircases of residential buildings. As the analysis showed, the dynamics of deliberate destruction and theft of meters practically coincides with the onset of cold weather with insufficient heating of apartments. IN in this case destruction and theft of meters should be considered as a unique form of protest of the population against the inability of local administrations to provide normal living conditions. The worsening situation with heat supply to the population inevitably leads to an increase in commercial losses of electricity, which has already been confirmed sad experience Far Eastern and some Siberian energy systems.
Electrical methods of electricity theft.
Most common in Russia electrically Theft of electricity is the so-called “surge” on an overhead line made with bare wire. The following methods are also widely used:
load current phase inversion;
application various types“unwinders” for partial or full compensation of the load current with a change in its phase;
shunting the meter's current circuit - installing so-called “short circuits”;
grounding the neutral load wire;
violation of the alternation of phase and neutral wires in a network with a grounded neutral of the supply transformer.
If meters are connected via measuring transformers, the following can also be used:
disconnection of CT current circuits;
replacing normal VT fuses with blown ones, etc.
Magnetic methods of energy theft.
Application of magnets with outside meter may affect its performance. In particular, when using older types of induction counters, it is possible to slow down the rotation of the disk using a magnet. Currently, manufacturers are trying to protect new types of meters from the influence of magnetic fields. Therefore, this method of electricity theft is becoming increasingly limited.
Other methods of electricity theft
Exists whole line methods of theft of electricity of purely Russian origin, for example, theft due to the frequent change of owners of a particular company with the permanent re-issuance of contracts for the supply of electricity. In this case, energy sales are not able to keep track of the change in owners and receive payment for electricity from them.
Commercial losses of electricity due to the presence of ownerless consumers.
Crisis phenomena in the country, the emergence of new joint-stock companies have led to the fact that in most energy systems in recent years, residential buildings, hostels, and entire residential villages have appeared and have existed for quite some time, which are not on the balance sheet of any organizations. Residents do not pay anyone for electricity and heat supplied to these houses. Attempts by energy systems to disconnect defaulters are not yielding results, as residents are again connecting to the grid without permission. The electrical installations of these houses are not maintained by anyone; technical condition threatens accidents and does not ensure the safety of life and property of citizens.
Commercial losses caused by non-simultaneity of payments for electricity by household consumers - the so-called “seasonal component”.
This very significant component of commercial electricity losses occurs due to the fact that residential consumers are objectively unable to simultaneously take meter readings and pay for electricity. As a rule, payments lag behind actual electricity consumption, which, of course, introduces an error in determining the actual useful supply by a household consumer and in calculating the actual imbalance of electricity, since the lag can be from one to three months or more. As a rule, in the autumn-winter and winter-spring periods of the year there are underpayments for electricity, and in the spring-summer and summer-autumn periods these underpayments are compensated to a certain extent. In the pre-crisis period, this compensation was almost complete, and annual electricity losses rarely had a commercial component. Currently, autumn-winter and winter-spring seasonal underpayments for electricity far exceed in most cases the total payment in other periods of the year. Therefore, commercial losses occur by month, quarter and for the year as a whole.
Errors in calculating technical losses of electricity in electrical networks.
Because commercial power losses cannot be measured. They can be calculated with varying degrees of error. The value of this error depends not only on the errors in measuring the volume of electricity theft, the presence of “orphan consumers”, and other factors discussed above, but also on the error in calculating technical losses of electricity. The more accurate the calculations of technical losses of electricity are, the more accurate the estimates of the commercial component will be, the more objectively it is possible to determine their structure and outline measures to reduce them.
Introduction
Literature review
1.2 Load power losses
1.3 No-load losses
1.4 Climate-related electricity losses
2. Methods for calculating electricity losses
2.1 Methods for calculating electricity losses for various networks
2.2 Methods for calculating electricity losses in 0.38-6-10 kV distribution networks
3. Programs for calculating electricity losses in electrical distribution networks
3.1 The need to calculate technical losses of electricity
3.2 Application of software for calculating electricity losses in distribution networks 0.38 - 6 - 10 kV
4. Rationing of electricity losses
4.1 Concept of loss standard. Methods for setting standards in practice
4.2 Standard characteristics of losses
4.3 The procedure for calculating standards for electricity losses in distribution networks 0.38 - 6 - 10 kV
5. An example of calculating electricity losses in 10 kV distribution networks
Conclusion
Bibliography
Introduction
Electrical energy is the only type of product that does not use other resources to move it from places of production to places of consumption. For this, part of the transmitted electricity is consumed, so its losses are inevitable; the task is to determine their economically justified level. Reducing electricity losses in electrical networks to this level is one of the important areas of energy saving.
Throughout the entire period from 1991 to 2003, total losses in Russian power systems grew both in absolute value and as a percentage of electricity supplied to the network.
The growth of energy losses in electrical networks is determined by the action of completely objective laws in the development of the entire energy industry as a whole. The main ones are: the tendency to concentrate electricity production at large power plants; continuous growth in electrical network loads associated with a natural increase in consumer loads and lagging growth rates bandwidth networks on the growth rate of electricity consumption and generating capacity.
In connection with the development of market relations in the country, the importance of the problem of electricity losses has increased significantly. The development of methods for calculating, analyzing electricity losses and selecting economically feasible measures to reduce them has been carried out at VNIIE for more than 30 years. To calculate all components of electricity losses in networks of all voltage classes of JSC-Energo and in the equipment of networks and substations and their regulatory characteristics, a software package has been developed that has a certificate of conformity approved by the Central Dispatch Office of the UES of Russia, Glavgosenergonadzor of Russia and the Department of Electric Networks of RAO UES of Russia.
Due to the complexity of calculating losses and the presence of significant errors, recently special attention has been paid to the development of methods for normalizing electricity losses.
The methodology for determining loss standards has not yet been established. Even the principles of rationing have not been defined. Opinions on the approach to standardization lie in a wide range - from the desire to have an established firm standard in the form of a percentage of losses to control of “normal” losses through constantly carried out calculations on network diagrams using appropriate software.
Electricity tariffs are set based on the obtained energy loss rates. Tariff regulation is entrusted to the state regulatory bodies FEC and REC (federal and regional energy commissions). Energy supply organizations must justify the level of electricity losses that they consider appropriate to include in the tariff, and energy commissions must analyze these justifications and accept or adjust them.
This paper examines the problem of calculating, analyzing and rationing electricity losses from a modern perspective; The theoretical provisions of the calculations are presented, a description of the software that implements these provisions is given, and the experience of practical calculations is outlined.
Literature review
The problem of calculating electricity losses has been worrying power engineers for a very long time. In this regard, very few books on this topic are currently published, since little has changed in fundamental structure networks. But at the same time enough is produced a large number of articles where old data is clarified and new solutions to problems related to the calculation, regulation and reduction of electricity losses are proposed.
One of the latest books published on this topic is the book by Yu.S. Zhelezko. "Calculation, analysis and regulation of electricity losses in electrical networks". It most fully presents the structure of electricity losses, methods for analyzing losses and the selection of measures to reduce them. Methods for normalizing losses are substantiated. The software that implements loss calculation methods is described in detail.
Previously, the same author published the book “Selection of measures to reduce electricity losses in electrical networks: A guide for practical calculations.” Here, the greatest attention was paid to methods for calculating electricity losses in various networks and the use of one or another method was justified depending on the type of network, as well as measures to reduce electricity losses.
In the book Budzko I.A. and Levin M.S. “Power supply to agricultural enterprises and populated areas,” the authors examined in detail the problems of power supply in general, focusing on distribution networks that supply agricultural enterprises and populated areas. The book also provides recommendations for organizing control over electricity consumption and improving accounting systems.
Authors Vorotnitsky V.E., Zhelezko Yu.S. and Kazantsev V.N. in the book “Electricity Losses in Electrical Networks of Power Systems” they examined in detail general issues related to reducing electricity losses in networks: methods for calculating and forecasting losses in networks, analyzing the structure of losses and calculating their technical and economic efficiency, planning losses and measures to reduce them.
In the article by Vorotnitsky V.E., Zaslonov S.V. and Kalinkini M.A. "Program for calculating technical losses of power and electricity in distribution networks 6 - 10 kV" describes in detail the program for calculating technical losses of electricity RTP 3.1 Its main advantage is ease of use and easy-to-analyze output of the final results, which significantly reduces personnel labor costs for the calculation.
Article by Zhelezko Yu.S. “Principles of regulation of electricity losses in electrical networks and calculation software” is devoted to the current problem of regulation of electricity losses. The author focuses on the targeted reduction of losses to an economically feasible level, which is not ensured by the existing rationing practice. The article also makes a proposal to use standard loss characteristics developed on the basis of detailed circuit calculations of networks of all voltage classes. In this case, the calculation can be made using software.
The purpose of another article by the same author entitled “Estimation of electricity losses caused by instrumental measurement errors” is not to clarify the methodology for determining the errors of specific measuring instruments based on checking their parameters. The author of the article assessed the resulting errors in the system for accounting for the receipt and supply of electricity from the network of an energy supply organization, which includes hundreds and thousands of devices. Special attention paid attention to systematic error, which currently turns out to be an essential component of the loss structure.
In the article by Galanov V.P., Galanov V.V. “The influence of power quality on the level of power losses in networks” pays attention to the current problem of power quality, which has a significant impact on power losses in networks.
Article by Vorotnitsky V.E., Zagorsky Ya.T. and Apryatkina V.N. “Calculation, standardization and reduction of electricity losses in urban electrical networks” is devoted to clarifying existing methods for calculating electricity losses, normalization of losses in modern conditions, as well as new methods for reducing losses.
In the article by Ovchinnikov A. “Electricity losses in distribution networks 0.38 - 6 (10) kV” the emphasis is on obtaining reliable information about the operating parameters of network elements, and above all about the loading of power transformers. This information, according to the author, will help to significantly reduce electricity losses in networks of 0.38 - 6 - 10 kV.
1. Structure of electricity losses in electrical networks. Technical losses of electricity
1.1 Structure of electricity losses in electrical networks
When transferring electrical energy Losses occur in each element of the electrical network. To study the components of losses in various elements networks and assessing the need for a particular measure aimed at reducing losses, an analysis of the structure of electricity losses is performed.
Actual (reported) electricity losses Δ W Otch is defined as the difference between the electricity supplied to the network and the electricity supplied from the network to consumers. These losses include components of various natures: losses in network elements that are purely physical in nature, electricity consumption for the operation of equipment installed at substations and ensuring the transmission of electricity, errors in recording electricity by metering devices and, finally, theft of electricity, non-payment or incomplete payment meter readings, etc.
Electricity losses in electrical networks occur quite often and there are reasons for this. Losses in electrical networks are considered to be the differences between the transmitted electrical energy on power lines and the recorded energy consumed by the consumer. Let's consider what measures are available to reduce losses.
Power loss in power lines: distance from power plant
Accounting and payment of all types of losses are regulated by law. When transporting energy over long distances from the producer to the consumer, some of the electricity is lost. This happens by various reasons, one of which is the voltage level that a typical consumer consumes (220 or 380 V). If you transport such electrical voltage directly from station generators, then you need to lay electrical networks with a diameter of electrical wire that will provide everyone with the required electrical current. Electrical wires will have a very large cross-section.
It will not be possible to place them on power lines, due to the unimaginable weight, laying them in the ground over long distances will be very expensive.
In order to eliminate this factor in electrical networks, they use high voltage lines electricity transmissions. Transferring energy with such electrical voltage, it is wasted many times over due to poor-quality contact of electrical conductors, which increase their resistance over the years. Losses increase with increasing air humidity - the leakage current on the insulators and on the corona increases. Losses in cables also increase when the insulation parameters of electrical wires are reduced. The electricity supplier sent the electricity to the supplying organization.
Accordingly, it must bring the parameters into the required parameters during transmission:
- Convert the products that were received into an electrical voltage of 6-10 kV.
- Distribute cables to receiving points.
- Then convert it back into electrical voltage in 0.4 kV wires.
Again losses, transformation during the operation of 6-10 kV and 0.4 kV electrical transformers. The average consumer is supplied with energy at the required voltage - 380-220 V. Transformers have their own efficiency and are designed for a specific load. If you overdo it with power or, on the contrary, if it is less than calculated, losses in the power grid will increase, regardless of the wishes of the supplier.
Another point is the discrepancy between the power of the transformer, which converts 6-10 kV into 220 V. If consumers take more energy than the power specified in the transformer’s passport, it either breaks down or cannot provide the required output parameters. As a result of a decrease in electrical voltage electrical devices operate in violation of the passport regime and, therefore, consumption increases.
What determines the voltage loss in wires?
The consumer took his 220 or 380 V at the electric meter. Now the energy that will be lost can be transferred to the end consumer.
Comprises:
- Heating losses of electrical wires when increased consumption due to calculations.
- Poor electrical contact in electrical switching devices.
- Capacitive and inductive nature of electrical load.
This also includes the use of old lighting fixtures, refrigeration equipment and other outdated technical devices.
Comprehensive measures to reduce electricity losses
Let's consider measures to reduce electrical energy losses in a cottage and apartment building.
Necessary:
- To fight it, you need to use electrical conductors that match the load. Today in electrical networks it is necessary to monitor the compliance of the parameters of electrical wires and the power that is consumed. In a situation where it is impossible to adjust these parameters and bring them back to normal values, you will have to put up with the fact that electricity is wasted on heating the conductors, so their insulation parameters change and the risk of fire in the room increases.
- Poor electrical contact: in switches this is the use of innovative designs with good non-oxidizing electrical contacts. Any oxide increases resistance. The same technique is used in starters. Switches – on/off system should use metal that is moisture-resistant and resistant to high temperature conditions. The contact depends on the high-quality pressing of the pole to the plus.
- Reactive load. All electrical appliances that are not incandescent light bulbs or old-style electric stoves have a reactive component of energy consumption. Any inductance, when current is applied to it, resists the flow of energy through it due to the developing magnetic induction. After a certain period, a phenomenon such as magnetic induction, which prevented the current from flowing, helps its flow and adds some electricity to the electrical network, which is harmful to the general electrical networks. A special process called eddy currents develops; they distort the normal meter readings and make negative changes to the parameters of the energy that is supplied. The same thing happens with a capacitive electrical load. Currents spoil the parameters of the energy supplied to the consumer. The struggle lies in the use of modern compensators, depending on the parameters of the electrical load.
- Use of old lighting systems (incandescent lamps). Their efficiency has a maximum of 3-5%. The remaining 95% goes to heating the filament and, as a result, heating environment and to radiation that a person does not perceive. Therefore, it is not rational to improve here. Other types of light supply have appeared - fluorescent light bulbs, LEDs, which have become actively used today. The efficiency of fluorescent light bulbs reaches 7%, and for LEDs the percentage is close to 20. The use of LEDs allows you to save money right now and during operation due to durability - compensation for expenses of up to 50,000 hours.
It is also impossible not to say that you can reduce electricity losses in your home by installing a voltage stabilizer. According to the town hall, it can be found in specialized companies.
How to calculate electricity losses: conditions
The easiest way to calculate losses is in an electrical network where only one type of electrical wire with one cross-section is used, for example, if only aluminum electrical cables with a cross-section of 35 mm are installed at home. In life, systems with one type of electrical cable are almost never encountered; usually different electrical cables are used to supply buildings and structures. In such a situation, to obtain accurate results, it is necessary to separately count for individual sections and lines of the electrical system with a variety of electrical cables.
Losses in the electrical network at the transformer and before it are usually not taken into account, since individual electrical devices for metering consumed electricity are placed in the electrical circuit after such special equipment.
Important:
- Calculation of energy losses in a transformer is carried out on the basis of technical documents of such a device, which will indicate all the parameters you require.
- It must be said that any calculations are performed in order to determine the value of the maximum losses during current transmission.
- When making calculations, it must be taken into account that the power of the electrical network of a warehouse, manufacturing plant or other facility is sufficient to supply all energy consumers connected to it, that is, the system can function without overvoltage even at maximum load, at each facility that is turned on.
The amount of allocated electrical power can be found out from the agreement concluded with the energy supplier. The amount of losses always depends on the power of the electrical network and its consumption through the potter. The more electrical voltage consumed by objects, the higher the losses.
Technical losses of electricity in networks
Technical energy losses - losses that are caused by the physical processes of transportation, distribution and transformation of electricity are identified through calculations. The formula used for the calculation is: P=I*U.
- Power is equal to current multiplied by voltage.
- By increasing the voltage when transmitting energy in electrical networks, the current can be reduced several times, which will make it possible to use electrical wires with a much smaller cross-section.
- The pitfall is that there are losses in the transformer that someone must compensate for.
Technological losses are divided into conditionally constant and variable (depending on the electrical load).
What are commercial power losses?
Commercial energy losses are electrical losses, which are defined as the difference between absolute and technological losses.
Need to know:
- Ideally, commercial electrical energy losses in the power grid should be zero.
- It is obvious, however, that in reality the supply to the power grid, useful supply and technical losses are determined with errors.
- Their differences are in fact the structural elements of commercial electrical losses.
They should, if possible, be reduced to a minimum value through the implementation of certain measures. If this is not possible, you need to make amendments to the meter readings; they compensate for systematic errors in electrical energy measurements.
Possible losses of electricity in electrical networks (video)
Losses of electrical energy in power grids lead to additional costs. Therefore, it is important to control them.
To view photographs posted on the site in an enlarged size, you need to click on their reduced copies.
Methodology for calculating technological losses of electricity
in the power line VL-04kV of the gardening partnership
Until a certain time, the need to calculate technological losses in power lines, owned by SNT as a legal entity, or by gardeners who have garden plots within the boundaries of any SNT, was not needed. The board didn't even think about it. However, meticulous gardeners, or rather doubters, forced us to once again throw all our efforts into ways to calculate electricity losses in Power lines. The easiest way, of course, is to stupidly contact a competent company, that is, an electricity supply company or a small firm, which will be able to calculate the technological losses in their network for gardeners. Scanning the Internet made it possible to find several methods for calculating energy losses in an internal power line in relation to any SNT. Their analysis and analysis of the necessary values for calculating the final result made it possible to discard those of them that involved measuring special parameters in the network using special equipment.
The methodology offered to you for use in a gardening partnership is based on knowledge of the basics of transmission electricity along the lines of a basic school physics course. When creating it, the standards of the order of the Ministry of Industry and Energy of the Russian Federation No. 21 of 02/03/2005 “Methodology for calculating standard electricity losses in electrical networks” were used, as well as the book by Yu.S. Zhelezko, A.V. Artemyev, O.V. Savchenko "Calculation, analysis and regulation of electricity losses in electrical networks", Moscow, JSC "Publishing House NTsENAS", 2008.
The fact is that if the total of gardeners and SNT electrical installations exceeds the amount of electricity allocated to everyone, then accordingly calculation of technological losses must be specified for a different amount of kW/h consumed. The more electricity the SNT consumes, the greater the losses will be. Adjustment of calculations in this case is necessary to clarify the amount of payment for technological losses in the internal network, and its subsequent approval at the general meeting.
Those. 3 wires (3 phases) and one neutral wire are connected to the SNT distribution board, where the common three-phase meter is located. Accordingly, 20 gardeners’ houses are evenly connected to each phase, for a total of 60 houses.
To calculate losses, the following formula is used:
ΔW = 9.3· W²·(1 + tan²φ)·K f ²·K L.L
D F
ΔW- electricity losses in kW/h;
W- electricity supplied to power line for D (days), kW/h (in our example 63000 kW/h or 63x10 6 W/h);
K f- load curve shape factor;
To L- coefficient taking into account the load distribution along the line ( 0,37 - for a line with a distributed load, i.e. 20 gardeners’ houses are connected for each phase of three);
L- line length in kilometers (in our example 2 km);
tgφ- reactive power factor ( 0,6 );
F- wire cross-section in mm²;
D- period in days (in the formula we use the period 365 days);
K f²- chart fill factor, calculated by the formula:
K f ² = (1 + 2K z)
3K z
Where K z- graph filling factor. In the absence of data on the shape of the load graph, the value is usually taken - 0,3 ; Then: Kf² = 1.78.
Calculation of losses using the formula is performed for one feeder line. There are 3 of them, 2 kilometers each.
We assume that the total load is evenly distributed along the lines inside the feeder. Those. annual consumption on one feeder line is equal to 1/3 of total consumption.
Then: W sum. = 3 * ΔW in line.
The electricity supplied to gardeners per year is 63,000 kW/h, then for each feeder line: 63000 / 3 = 21000 kW/h or 21 10 6 W/h- it is in this form that the value is present in the formula.
ΔW line =9.3· 21² 10 6 (1+0.6²) 1.78 0.37. 2
=
365 35
ΔW line = 573.67 kW/h
Then for a year along three feeder lines: ΔW sum. = 3 x 573.67 = 1721 kW/h.
Losses for the year in Power lines in percentages: ΔW sum. % = ΔW sum /W sum x 100% = 2.73%
Provided that all energy consumption metering devices are placed on power transmission line supports, then the length of the wire from the point of connection of the line belonging to the gardener to his individual device accounting will amount to only 6 meters(total length of support 9 meters).
The resistance of a SIP-16 wire (self-supporting insulated wire, cross-section 16 mm²) per 6 meters of length is only R = 0.02ohm.
P input = 4 kW(let’s take it as the calculated permitted electrical power for one house).
We calculate the current strength for a power of 4 kW: I input = P input /220 = 4000W / 220V = 18 (A).
Then: dP input = I² x R input = 18² x 0.02 = 6.48W- losses per 1 hour under load.
Then the total losses for the year in the line of one connected gardener: dW input = dP input x D (hours per year) x K use max. load = 6.48 x 8760 x 0.3 = 17029 Wh (17.029 kWh).
Then the total losses in the lines of 60 connected gardeners per year will be:
dW input = 60 x 17.029 kW/h = 1021.74 kW/h
ΔW sum. total = 1721 + 1021.24 = 2745.24 kW/h
ΔW sum. %= ΔW sum / W sum x 100%= 2745.24/63000 x 100%= 4.36%
Total: In an internal overhead power line SNT with a length of 2 kilometers (3 phases and zero), a wire with a cross-section of 35 mm², connected by 60 houses, with a total consumption of 63,000 kW/h of electricity per year, the losses will be 4.36%
- If there are several feeders in the SNT, which differ from each other in length, wire cross-section and the amount of electricity passing through them, then the calculation must be done separately for one line and each feeder. Then sum up the losses for all feeders to derive the total percentage of losses.
- When calculating losses on a section of a line owned by a gardener, the resistance coefficient (0.02 ohms) of one SIP-2x16 wire at 20°C with a length of 6 meters was taken into account. Accordingly, if your SNT meters do not hang on supports, then it is necessary to increase the resistance coefficient in proportion to the length of the wire.
- When calculating losses on a section of a line owned by a gardener, you should also take into account the permitted power for the house. With different consumption and permitted power, the losses will be different. It would be correct and appropriate to distribute power depending on needs:
for a gardener-dacha resident - 3.5 kW (i.e. corresponds to the limitation on the 16A residual current circuit breaker);
for a gardener permanently residing in SNT - from 5.5 kW to 7 kW (respectively, overload circuit breakers for 25A and 32A). - When obtaining data on losses for residents and summer residents, it is advisable to establish different payments for technological losses for these categories of gardeners (see point 3 of the calculation, i.e., depending on the value I- current strength, for a summer resident at 16A, the losses will be less than for a permanent resident at 32A, which means there should be two separate calculations of losses at the entrance to the house).
Important Notes:
Example: In conclusion, it should be added that our SNT "Pishchevik" ESO "Yantarenergo" at the conclusion of the Electricity Supply Agreement in 1997 established the value calculated by them technological losses from TP to installation site common device electricity metering equal to 4.95% per 1 kW/h. The calculation of line losses using this method was 1.5% maximum. It’s hard to believe that the losses in the transformer, which SNT does not belong to, still amount to almost 3.5%. And according to the Agreement, the losses of the transformer are not ours. It's time to sort this out. You will soon learn about the result.
Let's continue. Previously, our accountant at SNT charged 5% per kWh for losses established by Yantarenergo and 5% for losses within SNT. Naturally, no one expected anything. The calculation example used on the page corresponds almost 90% to reality when operating an old power line in our SNT. So this money was enough to pay for all the losses in the network. Even surpluses remained and gradually accumulated. This emphasizes the fact that the technique works and is fully consistent with reality. Compare for yourself: 5% and 5% (there is a gradual accumulation of surplus) or 4.95% and 4.36% (no surplus). Those., calculation of electricity losses corresponds to actual losses.
Chapter 2 The problem of reducing commercial electricity losses in electrical networks
Electricity losses in electrical networks are conventionally divided into technical and commercial.
TO technical include losses of electricity caused by physical processes occurring during the transmission of electricity through electrical networks and expressed in the conversion of part of the electricity into heat in network elements. Technical losses cannot be measured. Their values are obtained by calculation based on the known laws of electrical engineering. The amount of technical losses in power supply systems is included in the tariff cost of electricity. Electricity cannot be transported without technical losses; they can only be reduced with the help of appropriate technical and operational measures.
In power systems, there are specific standards for technical losses of electrical energy in electrical networks, determined on the basis of the resolution of the Federal Energy Commission (FEC) of the Russian Federation dated March 17, 2000 No. 14/10 “On approval of standards for technological consumption of electrical energy (power) for its transmission (losses) ), adopted for the calculation and regulation of tariffs for electrical energy (the amount of payment for services for its transmission).”
Integrated standards for such losses are developed according to voltage levels and are divided into conditionally constant and variable.
Conditionally permanent losses of electricity determined depending on the passport data of electrical network equipment and the duration of operation during the billing period. Conditionally permanent losses in physical terms are taken into account when calculating tariff rates for services for the transmission of electrical energy for consumers connected to networks of the corresponding voltage level (range).
Variable electrical energy losses are determined in absolute units and as a percentage of the supply of electrical energy to the network of the corresponding voltage level and are taken into account when calculating the amount of payment for services for the transmission of electrical energy for consumers connected to networks of the corresponding voltage level (range).
For example, the specific standard for electrical energy losses in electric power organizations of OJSC Samaraenergo is 6.0 thousand kWh per year/km of electric networks with a voltage level of 0.4 kV, at medium voltage - 6.43 and at high voltage 4, 05 thousand kWh per year/km of electrical networks.
TO commercial include electricity losses caused by:
electricity theft;
discrepancy between meter readings and electricity payments by consumers and other reasons in the area of organizing control of electricity consumption (for example, unreliable metering due to malfunction of metering devices, incorrect connection of measuring voltage transformers and current transformers, unauthorized connection of pantographs or their connection in addition to meters, etc.);
errors in charges for supplied electricity due to inaccurate or unreliable information about the consumer, due to calculations using metering devices not at the border of the balance sheet, etc.;
non-payment of electricity by consumers on “self-payment”.
The presence of an unacceptably large number of defaulters has already become a common occurrence for energy sales organizations.
An increase in commercial losses leads to an increase in electricity tariffs.
Reducing commercial electricity losses in electrical networks represents one of the significant potential for energy saving and increasing the capacity of electrical networks.
One of the most significant components of commercial losses is theft of electricity, which has become alarming in recent years.
The largest number of thefts and the largest volumes of stolen electricity occur in the household sector. The reasons for this are, on the one hand, the constant increase in electricity tariffs with a simultaneous increase in the volume of its consumption and a decrease in the solvency of the population, and on the other hand, the relative availability and ease of implementation of one or another method of stealing electricity, imperfect designs of metering devices, primary and secondary circuits their switching, unsatisfactory technical condition of measuring transformers and voltage transformers, lack of a specific legal framework for bringing electricity thieves to justice, prohibitively high (in many cases inaccessible for low-energy organizations) fees for connecting to electrical networks, etc.
For a number of objective reasons, it is not possible to contain the rise in electricity prices in the near future. Due to the peculiarities of the structure of the domestic electric power industry, consumers cannot influence the cost of electricity in either the wholesale or retail markets. At the same time, due to the decline in industrial production volumes, the share of electrical energy consumption in the household and small-motor sectors increased (in percentage terms).
A significant increase in electricity consumption in the household sector causes significant overloads in district supply lines and transformer substations, which, in turn, contributes to the occurrence (threat of occurrence) of emergency situations in electrical installations and is fraught with undesirable consequences (fires, electrical injuries, underproduction and defective products, etc. .).
When electricity is stolen, part of the power turns out to be unaccounted for, which leads to exceeding the maximum permissible load and, as a consequence, to network overloads and disconnection of consumers by automatic protective devices.
Many enterprises and organizations, especially in the field of small and medium-sized businesses, also cannot cope with rising tariffs and become defaulters, and some of them take the path of stealing electricity.
For example, the cost of one of the stolen bakeries in Far East electricity is about 1.4 million rubles. with monthly electricity consumption of the entire region (in monetary terms) 7.5 million rubles, i.e. approximately a fifth of the total consumption of the local energy company. In another Siberian city, three small defaulting enterprises were discovered at once, causing losses to the local energy system in the amount of more than 1.5 million rubles. In Nizhny Novgorod, one of the paid parking lots was disconnected four times for unauthorized connection to the power grid, and the total amount of losses from the theft of electricity in Nizhny Novgorod, according to the director of Energosbyt of Nizhnovenergo OJSC, amounts to millions of rubles (according to information from the Regional News Agency "Kremlin" dated 07.04 .2005).
Thus, there are massive non-payments to energy supply organizations in both the utility and industrial sectors.
At the same time, the management of energy supplying organizations believes (in its own right) that electricity tariffs, for example in the household sector, are underestimated (preferential). In this regard, there is no doubt about the further increase in electricity tariffs, which will cause a corresponding increase in the volume of its theft.
This situation is not consistent with the main goals of the Law of the Russian Federation “On State Regulation of Tariffs for Electricity and thermal energy V Russian Federation”, adopted by the State Duma of the Russian Federation on March 10, 1995, which states that one of the main goals of state regulation of tariffs is “protecting the economic interests of consumers from monopoly increases in tariffs.”
Currently, another significant factor has arisen that encourages consumers of electrical energy to connect to electrical networks without authorization without obtaining permission to connect power and, therefore, without drawing up an agreement technological connection to electrical networks and energy supply contracts: a significant increase in the amount of fees for connecting power.
In accordance with the Federal Law “On Electric Power Industry” (Article 26), the fee for technological connection to electrical networks is charged once. The amount of this fee is established by the federal executive body. In this case, the inclusion of electric energy transmission services in the fee is not allowed.
According to the Rules for the technological connection of power receiving devices (power installations) of legal entities and individuals to electrical networks, approved by Decree of the Government of the Russian Federation of December 27, 2004 No. 861, in order to obtain permission to connect power, electricity consumers must conclude an agreement with energy supply organizations for technological connection to electrical networks and in accordance with this agreement, make a one-time payment for connecting power to electrical networks.
The amount of fees for connecting power to the electrical networks of energy supplying organizations is regulated by the order of the Federal Tariff Service (FTS) of the Russian Federation dated February 15, 2005 No. 22-e/5 “On approval of the Guidelines for determining the amount of fees for technological connection to electrical networks.” It has increased sharply recently.
The highest fees for connecting to power grids (due to the relatively higher cost of constructing power units, cable communications and the shortage of free land, as well as the fact that in Moscow by 2006 all reserves of generating sources had already been exhausted) occur in Moscow, where 1 kW of connected power is paid in the amount of 53,216 rubles. (in view of VAT).
For comparison: in Mosenergo OJSC the amount of payment for power connection is based on the Moscow Government Decree No. 261 dated May 12, 1992 long time was 143 rubles. 96 kopecks (including VAT) per 1 kW of connected power.
Obviously, not every consumer of electricity is able to pay such a huge amount, and one can only guess how many of them will be forced to connect to electrical networks without permission without permission from the energy supply organization to connect power and without concluding a technological connection agreement and an energy supply agreement with it.
Given the ongoing shortage of generating capacity and the resulting growing problems in the system of energy supply organizations, we can expect a further increase in fees for connecting to electrical networks. This is all the more likely since the fee for technological connection is set by state regulatory bodies and, like all tariffs, will be reviewed annually.
The power connection fee is used by the energy supplying organization as the last source of financing.
Energy supply organizations have another significant reason limiting the ability to connect consumers to power grids: the availability technical feasibility technological connection.
Criteria for availability of technical capability established by the Rules for the technological connection of power receiving devices (power installations) of legal entities and individuals, approved by Decree of the Government of the Russian Federation No. 861 of December 27, 2004.
There are two criteria for the technical possibility of technological connection:
location of the power receiving device, in respect of which an application for technological connection has been submitted, within the territorial boundaries of service of the corresponding network organization;
no restrictions on connected power in the network node to which the technological connection must be made.
In order to verify the validity of the electric grid company’s determination of the lack of technical possibility, the consumer has the right to contact Rostechnadzor to obtain an opinion on the presence (absence) of the technical possibility of technological connection.
The continuous increase in electricity tariffs leads to a decrease in the effectiveness of energy saving measures, an increase in the number of defaulters and to massive theft of electricity. While RAO UES of Russia provides arguments and justifications for the advisability of introducing the highest possible tariffs for electricity, for this reason it itself suffers considerable losses due to commercial losses in electric networks, including due to the theft of electricity.
There is also back side problems: the increase in the theft of electricity, in turn, affects the increase in tariffs.
At the same time, methods of stealing electricity are constantly being improved. As they are identified, new, more sophisticated and hidden ways, often undetectable and preventable.
The problem of reducing commercial losses has become so important that it has come under the control of the Government of the Russian Federation, which, in the above-mentioned resolution of December 27, 2004 No. 861, instructed the Ministry of Industry and Energy of the Russian Federation to develop and approve within three months a methodology for determining regulatory and actual losses electrical energy in electrical networks. Loss standards must be established by the authorized federal executive body in accordance with the specified methodology.
OJSC Roskommunenergo and CJSC ASU Mosoblelektro, with the participation of the Russian Association of Utilities, developed Methodological recommendations for determining electrical energy losses in urban electrical networks with a voltage of 10(6)-0.4 kV, approved by Gosenergonadzor on 09.11.2000.
According to these Methodological Recommendations, calculations of losses and optimization of electrical network modes should be carried out using appropriate software systems. A special section is devoted to measures to reduce electricity losses.
In the Concept of Strategy of RAO UES of Russia for 2003–2008. “5+5” states that the main measures to reduce commercial losses are:
timely audit work;
control checks of end consumers;
improvement of the commercial and technological accounting system based on automated systems control, accounting and management of power consumption (ASKUE) and automated systems for technological management of power consumption (ASTUE);
automation and implementation of information technologies.
The principles of using accounting tools include the need to determine commercial losses of electricity, as well as compiling and monitoring the balance of power and electricity for individual nodes of electrical networks.
The problem of reducing commercial electricity losses is being actively addressed by experts in this field. It should be noted the work of Doctor of Technical Sciences. V. Vorotnitsky (JSC VNIIE). For example, in a joint study with V. Apryatkin (JSC Electric Networks, Klin), the damage from commercial losses in electrical networks was determined. Absolute value of commercial electricity losses from 1994 to 2001. increased from 78.1 to 103.55 billion kWh, and relative electricity losses increased from 10.09 to 13.1%, and in some regions they reached 15–20%, and in certain distribution networks – 30–50% (according to the information and reference publication “News of Electrical Engineering”. 2002. No. 4).
Based on the results of these studies, the main components of commercial losses listed above were determined. At the same time, the share of electricity theft in commercial losses is quite high.
Large-scale theft of electricity occurs in almost every region of the country. Let's give a few examples.
For 6 months of 2004, the energy sales company Dalenergo (Primorsky Territory) identified more than 700 cases of theft of electrical energy by legal entities in the amount of 11 million 736 rubles.
According to information from the Independent Political Bulletin, the Accounts Chamber of the Russian Federation revealed the theft of electricity worth 443 million rubles on Sakhalin; At the same time, current electricity losses amount to up to 30%.
The Ryazanovsky fish hatchery in the Khasansky district was cut off from power supply due to the fact that the plant management refused to pay 883 thousand rubles. unmetered electricity consumption (the company voluntarily connected in addition to electricity metering devices).
According to the Volga newspaper, in Astrakhan the losses of power engineers in the 1st quarter of 2005 alone amounted to 16 million rubles. During the federal campaign “Honest Kilowatt”, raid teams identified 700 cases of electricity theft by residents of the region.
According to the information and reference publication “News of Electrical Engineering” (2002. No. 4), losses from electricity theft in networks with voltages up to 1000 V in the system of JSC Lenenergo amount to about 400 million kWh per year.
According to the Press Center of Chitaenergo OJSC, in just 6 months of 2004, 869 cases of electricity theft worth more than 2.5 million rubles were recorded in Chita;
According to the press service of OJSC Krasnoyarskenergo, in 2004 the damage to the energy company from electricity theft amounted to about 4 million rubles.
According to the BANKO-FAX Information Server, in 2004, due to the theft of electricity in the power grids of Altaienergo OJSC, the energy company suffered a loss of 125 million kWh, amounting to almost 155 million rubles.
A detailed listing of episodes of electricity theft is beyond the scope of this book; a huge number of such examples can be found in various open sources.
The following factors create favorable conditions for electricity theft:
lack of proper government control over the commercial sale of electricity;
constant increase in electricity tariffs;
availability and simplicity of technical implementation of methods of stealing electricity (installation of switching devices in front of electricity metering devices, the possibility of deliberately underestimating the calculated losses of active power when installing commercial meters on the low voltage side of subscriber transformers, availability of primary and secondary switching circuits of metering devices, etc.);
lack of an effective legal framework for bringing electricity thieves to disciplinary, administrative and criminal liability.
As a result, two problems have now sharply worsened for energy supply organizations: non-payments for consumed electricity and its theft.
If, to solve the first problem, sales and network organizations take vigorous measures (see Appendix 1), using the relevant legal regulations, including departmental ones (for example, “Regulations on the basics of organizing energy sales work with energy consumers”, approved by RAO “UES of Russia” 02/14/2000), then in relation to electricity thieves there is no such regulatory documentation and, accordingly, proper measures to identify the facts of theft and bring the thieves to justice are not taken.
The legality of bringing the perpetrators of electricity theft to administrative or criminal liability in the manner prescribed by law is determined by the fact that electricity has become a product (product) of a specific owner, for the theft of which specific penalties are provided.
It still remains unclear and not fully resolved the question of which body - the State Energy Supervision (Rostechnadzor) or energy supply organizations - should monitor the presence of electricity thefts, identify facts of theft, draw up the relevant legal documents and send them to court. The ambiguity in this issue is aggravated by the fact that in general terms the problem of rational use and metering of electricity is reflected in the guidance materials of both regulatory structures.
So, for Rostechnadzor this problem is reflected in the following documents:
Regulations on State Energy Supervision in the Russian Federation, approved by Decree of the Government of the Russian Federation dated August 12, 1998 No. 938, which, in particular, states that “the main task of Gosenergonadzor is to monitor... the rational and efficient use of electricity”;
Rules for the technical operation of consumer electrical installations (PTEEP), ch. 2.11 “Means of control, measurement and accounting”;
PUE, ch. 1.5 “Electricity metering”;
Interindustry rules on labor protection (safety rules) during the operation of electrical installations (IPBEE), ch. 8 “Relay protection and electrical automation devices, measuring instruments and electricity metering devices, secondary circuits”;
a number of departmental documents, for example, information letter of Gosenergonadzor dated August 21, 2000 No. 32–11–05/11 “On the participation of Gosenergonadzor in the work of RAO UES of Russia to improve electricity metering for household and small-engine consumers,” etc.
Energy sales and electric grid companies in this area are guided by decrees of the Government of the Russian Federation (in particular, decrees dated December 27, 2004 No. 861 and dated August 31, 2006 No. 530), contracts for technological connection to power grids and energy supply contracts, as well as a number of other documents ( For example, technical specifications for installation of metering devices).
In addition, both of these control structures participate in general commissions for auditing, checking the serviceability and operation of metering equipment, for example, when drawing up an act on the calibration of electric meters, an act on the audit and labeling of electrical energy metering devices (see Appendix 2), act on drawing up the balance of electricity, etc.
The situation is further complicated by the fact that the energy supply agreement is concluded between the consumer of electrical energy (subscriber) and the energy sales company, and instructions and recommendations for its execution are given by a third party - Rostechnadzor.
Coordination of the electricity supply project in terms of electricity metering is entrusted to the energy supply organization, and in full - to Rostekhnadzor.
On the one hand, by decision of the Government of the Russian Federation dated January 23, 2001 No. 83-r, the implementation of state policy in the field of energy saving is entrusted to the State Energy Supervision (Rostechnadzor), and on the other hand, the functions of the inspectorate of Rostechnadzor (for example, when carrying out planned activities on implementation of state control of consumers of electrical energy, when inspecting newly introduced and reconstructed electrical installations for their approval for operation, etc.) measures to identify and prevent the theft of electricity are not included.
Such ambiguity and not entirely specific formulation of the problem, the absence in all of the above regulatory documents even the specific term “electricity theft” and, in addition, the self-service system itself when taking readings from metering devices and consumer settlements with energy sales organizations creates favorable conditions for its theft and gives rise to impunity.
This suggests a disappointing conclusion that market mechanisms in the electric power industry alone, in the absence of state control, will not allow ensuring effective solution energy saving problems.
Against the backdrop of the inaction of energy supply organizations in the fight against electricity thefts, the activities of the management and specialists of Rostechnadzor acquire great importance and create the preconditions for a successful solution to the problem of electricity theft.
It is easy to see that the amount of damage from the theft of electricity only in the distribution system of JSC-Energo is extremely large.
In the order of RAO UES of Russia dated 08/07/2000 “On the creation modern systems Accounting and Control of Electricity Consumption" indicates that on the balance sheet of JSC-Energo there are approximately 21 million low-ampere single-phase meters, mainly for household electricity consumers.
If we assume a deliberately underestimated figure of electricity theft at the level of 1%, then it turns out that 210 thousand single-phase meters are in the mode of recording stolen electricity. If for an ordinary two-room apartment the consumption is approximately 150 kWh per month per meter, then in the end the amount of stolen electricity will be equal to 31.5 million kWh or, in monetary terms (with a one-rate tariff for household consumers on average 2 rubles. for 1 kWh), – 63 million rubles. per month. On an annual basis, this value will be at least about 760 million rubles. The reality of such enormous damage is confirmed by inspections to identify thefts of electricity, as well as by the data given in the above-mentioned order of RAO UES of Russia, which states that AO-energos lose on average 12-15% of payments for this group of consumers.
The actual damage to JSC-Energo is much higher than the estimate obtained, since the above estimated and obviously underestimated calculation did not include, for example, the theft of electricity from industrial and household consumers in three-phase networks.
Financial losses of JSC-Energo due to the lack and (or) imperfection of electricity accounting means annually amount to more than 15 billion rubles. And this is despite the volume of investments in the formation of the necessary accounting system being about 34 billion rubles.
One more unfavorable factor should be taken into account: when an unauthorized unauthorized connection of a load to electrical networks occurs, the voltage level decreases, and other indicators of power quality may deteriorate. This leads to additional damage associated with a decrease in equipment productivity, deterioration in product quality, product defects, and in some cases, failures of some devices that are sensitive to deviations of power quality indicators from standardized values.
In addition, the theft of electricity distorts energy saving statistics and leads to an increase in the imbalance between generated and supplied electricity. Currently, an increasing number of energy supply organizations are faced with the problem of significant imbalances exceeding acceptable values.
Calculation, analysis and comparison of permissible imbalances with actual ones contribute to a real quantitative assessment of commercial losses in electrical networks and make it possible to monitor the reliability of electricity metering in all parts of the power supply system. All components of the balance, except for electricity losses in power transformers, must be measured by design and technical meters.
In accordance with the Standard Instructions for Electricity Accounting during its Generation, Transmission and Distribution, the value actual imbalance NBf in electrical networks should be determined by the formula
where Wп is the supply of electricity to the substation buses;
Wо – supply of electricity;
WS.N.– electricity consumption for own needs;
Wh.n.– electricity consumption for the economic needs of the substation;
Wp.n. – electricity consumption for production needs;
Wtr – losses of electricity in the power transformers of the substation.
An additional and unaccounted increase in the actual imbalance is caused by an increase in the Wo component in formula (1) due to the theft of supplied electricity, and the reported data on energy saving in these cases turn out to be underestimated according to the unaccounted share of commercial losses.
Determining the actual imbalance of electricity in regional electrical networks, electrical network enterprises, or in regional energos as a whole is possible if technical losses are calculated in networks of all voltage classes, including networks with a voltage of 0.38 kV.
In accordance with the requirements of the specified Standard Instructions, the value of the actual unbalance should not exceed the value of the permissible unbalance NBd (NBf? NBd), which is determined by the following formula
Where m– the total number of metering points recording the receipt of the largest flows of electricity and the delivery of electricity to especially large consumers (in relation to the corresponding structural unit);
?pi– error of the measuring complex i– th electricity metering points;
doi– share of electricity accounted for i-th metering point;
?p 3 – error of the measuring complex (type representative) of a three-phase consumer (power less than 750 kV–A);
?pl– error of the measuring complex (type representative) of a single-phase consumer;
n3 – number of metering points for three-phase consumers (except those included in the number m), for which the total relative transmission of electricity is d3 ;
n1 – number of metering points for single-phase consumers (except those included in the number m), for which the total relative transmission of electricity is d1 .
In the absence of a methodology for assessing economic damage from the theft of electricity, which cannot be developed due to the lack of representative (complete and reliable) statistical data on the facts of its theft, there is no solid foundation even for a rough estimate of the actual damage from electricity theft. And just a qualitative analysis of even a significant number of cases of electricity theft (which is still unknown and is unlikely to be known accurately in the future) is, of course, not enough to solve this problem.
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