Methodology for determining technological losses in electricity networks. Calculation of electricity losses in electrical networks

Electricity losses in electrical networks happen 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:

1. Convert the products that were received into an electrical voltage of 6-10 kV.
2. Distribute cables to receiving points.
3. 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 appliances 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.

Consists of:

1. Heating losses of electrical wires when increased consumption due to calculations.
2. Poor electrical contact in electrical switching devices.
3. 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:

1. 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 introduce normal indicators, you will have to put up with the fact that electricity is wasted on heating the conductors, so the parameters of their insulation change and the risk of fire in the room increases.
2. 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.
3. Reactive load. All electrical appliances that are not incandescent light bulbs electric hotplates old models 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.
4. 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. Coefficient useful action fluorescent light bulbs reach 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:

1. 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.
2. It must be said that any calculations are performed in order to determine the value of the maximum losses during current transmission.
3. When making calculations, it must be taken into account that the power of the warehouse electrical network, manufacturing enterprise or other object is sufficient to supply all energy consumers connected to it, that is, the system can operate without overvoltage even at maximum load, at each included object.

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.

1. Power is equal to current multiplied by voltage.
2. By increasing the voltage when transmitting energy in electrical networks, the current can be reduced significantly, which will make it possible to use electrical wires with a much smaller cross-section.
3. 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:

1. Ideally, commercial electrical energy losses in the power grid should be zero.
2. It is obvious, however, that in reality supply to the power grid, useful supply and technical losses are determined with errors.
3. 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 measurement errors electrical energy.

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.

Features of calculating energy loss standards for territorial network organizations

Papkov B.V., Doctor of Engineering. Sciences, Vukolov V. Yu., engineer.NSTU im. R. E. Alekseeva, Nizhny Novgorod

The features of calculating loss standards for territorial grid organizations in modern conditions. The results of a study of methods for calculating losses in low voltage networks are presented.

Issues related to the transport and distribution of electrical energy and power through electrical networks are resolved under the conditions of the natural monopoly of territorial grid organizations (TGOs). Economic efficiency their functioning largely depends on the validity of the materials provided to the state tariff regulation services. At the same time, serious efforts are required to calculate the standards for electrical energy losses.

A number of problems that arise at the stages of preparing supporting materials for loss standards, their examination, consideration and approval remain unresolved. Currently, TSO has to overcome the following difficulties:

the need to collect and process reliable initial data for calculating loss standards; insufficient number of personnel to collect and process measurement data of electrical network loads, identify non-contractual and unaccounted electricity consumption; lack of modern electricity metering devices for reliable calculation of electricity balances both for the network as a whole and for its individual parts: substations, lines, dedicated sections of the network, etc.;

lack of electricity metering devices to separate electricity losses from own consumption and for the provision of services for the transmission of electricity to sub-subscribers; specialized software from a number of TSOs; the necessary material, financial and human resources for the practical implementation of programs and measures to reduce losses; regulatory framework to combat non-contractual and unmetered electricity consumption;

the complexity and labor intensity of calculating loss standards (especially in 0.4 kV distribution networks), the practical impossibility of reliably assessing their accuracy;

insufficient development of methods for reliable assessment of the technical and economic efficiency of measures and programs for reducing electricity losses;

difficulties in developing, agreeing and approving consolidated forecast electricity balances for the regulated period due to the lack of appropriate methods and reliable statistics on the dynamics of balance components.

Particular attention should be paid to the calculation of electricity losses in 0.4 kV networks due to their exceptional social importance (in Russia as a whole they account for about 40% of the total length of all electrical networks). At this voltage, electrical energy is consumed by the final electrical receivers: in large-scale chemistry - 40-50%, in mechanical engineering - 90-95%, in the public utility sector - almost 100%. The quality and efficiency of power supply to consumers largely depend on the reliability of 0.4 kV networks and their load.

Calculation of loss standards in 0.4 kV networks is one of the most labor-intensive. This is due to the following features:

heterogeneity of the initial circuit information and its low reliability;

branching of overhead lines 0.4 kV, when calculating losses in which the presence of support circuits with the appropriate parameters is required;

dynamics of changes in circuit and especially operating parameters;

execution of network sections with different numbers of phases;

uneven loading of phases; uneven phase voltages on the buses of the supply transformer.

It must be emphasized that methods for calculating power and electricity losses in 0.4 kV networks must be adapted to the maximum extent to the circuit and operating parameters available in the operating conditions of the networks, taking into account the volume of initial information.

Inspection of 10 TSO Nizhny Novgorod region, performing calculations of loss standards, their examination and approval make it possible to structure the created TSOs into the following groups:

1. successors of JSC-Energo;
2. created on the basis of the services of the chief power engineer of an industrial enterprise in accordance with the restrictions of antimonopoly legislation;
3. created to ensure the operation of electrical equipment that turned out to be “orphaned” during the implementation of market reform in the field of industrial and agricultural production.

The emergence of organizations - legal successors of previously existing AO-energos - is associated with the restructuring and liquidation of RAO UES of Russia. The calculation and approval of loss standards for TSOs of this group require minimal intervention from third-party researchers, since this task is not new for them: they have a fairly long history, personnel with extensive calculation experience, and maximum information availability. Methodological materials are focused mainly on the operating features of this particular group of TSOs.

An analysis of the problems associated with determining loss standards for enterprises of the second group shows that today there is an acute shortage of personnel ready to apply the existing methodology for calculating loss standards, which is not adapted to the real operating conditions of such TSOs. IN in this case It is advisable to involve external specialized companies for calculations and approval of loss standards. At the same time, there is no need for expensive special certified software available from third-party researchers. If we consider the task of approving a tariff for electricity transport services through plant networks as a more general one, in which the calculation of the loss standard is just its component (albeit an important one), then a legal problem arises of the legality of using retrospective technical and economic information in the context of changing the form of servicing electrical equipment .

When calculating losses in 0.4 kV networks of such TSOs, the most acute problem is the division of a unified power supply system into transport and technological parts. The latter refers to sections of the transport network that directly provide the final conversion of electricity into other types. Taking into account the actual distribution of connection points for third-party consumers, the volume of useful supply by voltage level and the complexity of calculating losses in 0.4 kV networks, in almost all cases it is advisable to completely classify these networks as the technological part.

TSOs classified as the third group are formed as a result of forced measures taken by the state and private business to eliminate the unacceptable situation when, due to the abandonment of non-core activities or the bankruptcy of various enterprises, a large number of electrical installations (mainly with voltage 10-6-0.4 kV) was abandoned by the previous owners. Currently, the technical condition of many such electrical installations can be characterized as unsatisfactory. However, their removal from work is impossible due to social significance. Taking this into account, a program for the restoration of dilapidated and “orphan” networks is being implemented in the regions, the financing of which is carried out, including centrally, from the federal budget. In most cases, electrical equipment is accepted into the balance sheet by local governments, which solve the problem of ensuring its normal functioning. Based on the experience of the Nizhny Novgorod region, we can conclude that the main direction of use of this equipment is its lease to state and private specialized companies.

Due to the dispersion of networks of such TSOs across different administrative regions to solve problems of transmission and distribution of electricity, ensuring the operability of electrical networks (installation, adjustment, repair and maintenance electrical equipment and means of protecting electrical networks), two ways are possible: creating your own maintenance and repair service (which, due to covering a large territory, will lead to an increase in the duration of equipment maintenance) or concluding maintenance contracts with the services of JSC-Energo. In this case, efficiency will be ensured, but the feasibility of the existence of organizations of this type loses its meaning. Currently, TSOs of the third group are carrying out work on installing electricity metering units, financed within the framework of the regional program for the restoration of dilapidated networks and from other sources. The issues of organizing a system for collecting and processing information on electric energy meter readings are being resolved with the involvement of specialized organizations. However, the high cost and volume necessary work, as well as existing contradictions between participants in the process of forming an electricity metering system will require a long time for their complete completion.

Under the current tariff setting system for the transport of electrical energy, the basis of the calculation is information on the technical and economic characteristics of the electrical equipment used and retrospective information on the actual costs of operating the TSO in the previous (base) period. For newly created TSOs of the third group, this is an insurmountable obstacle.

From the point of view of calculating the standard for electrical losses, TSOs of this class create the greatest problems. The main ones:

there is practically no passport data for electrical equipment;

there are no single-line diagrams of electrical networks, support diagrams of overhead power lines (BJI) and route diagrams of laid cable lines (CL);

Some sections of overhead lines and cable lines of such networks do not have direct connections with other equipment of the considered TSOs and are elements of connections of other TSOs.

In this situation, it is possible to use decision-making methods in conditions of lack and uncertainty of initial information. This makes it possible to achieve positive results simply because reasonable preference is given to those options that turn out to be the most flexible and provide the greatest efficiency. One of them is the method of expert assessments. Its application for each specific TSO of the third group is the only possible way to quantify the indicators necessary to calculate electricity losses at initial stage functioning of network organizations.

As an example, let us consider the features of calculating the standards for electricity losses for an organization (conventionally called TSO-energo), the electrical equipment of which is dispersed over the territory of 17 districts of the Nizhny Novgorod region. The sources of initial information about electrical equipment and operating modes of TSO-energo at the time of the start of the survey were lease agreements for electrical equipment and structures, contracts for technical and operational services concluded by its administration with local branches of OJSC Nizhnovenergo and with the guaranteeing supplier of electricity in the region. Due to the impossibility at the initial stage of TSO-Energo’s functioning as an electrical grid organization to account for transported electrical energy using electric meters, the volumes of transmitted electricity were determined by calculation.

During the inspection of electrical installations, additional information was obtained on 0.4 kV networks powered by transformer substations leased by TSO-Energo from the administrations of only two districts of the region. As a result of analyzing the data obtained, experts qualitatively determined the configuration of 0.4 kV networks of the organization under study, divided the total length (total number of spans) of 0.4 kV feeders into main sections and branches (taking into account the number of phases), and obtained average values ​​of such parameters as number of 0.4 kV feeders per transformer substation (2.3); the cross-section of the head section of the power transmission line feeder is 0.4 kV (38.5 mm 2), the cross-section of cable (50 mm 2) and overhead (35 mm") power lines is 6 kV.

Information about 0.4 kV electrical networks in all 17 districts is structured based on extrapolation of the results of an analysis of the support circuits of electrical networks based on a sample of two. According to the expert opinion, these areas are typical for TSO-energo, and extrapolation of the sampling results does not distort big picture configuration of the organization's networks as a whole. Below are the obtained values ​​of the standard for electricity losses AW Hn3, thousand kWh (%), for a regulation period of 1 year, for networks 6-10 and 0.4 kV:

6-10 kV 3378.33 (3.78)

0.4 kV 12452.89 (8.00)

Total 15831.22 (9.96)

In the current situation, taking into account the state of electrical installations of most TSOs, the most

A more effective, and sometimes the only possible method for calculating losses in 0.4 kV networks was the method of estimating losses using generalized information about network circuits and loads. However, according to the latest edition, its use is possible only when the low-voltage network is powered by at least 100 transformer substations, which significantly limits the use of the method for calculating losses in TSO networks. Here, a situation is possible where the standard for electricity losses in low-voltage networks, obtained by calculation and justified by the presence of supporting documents, will be significantly lower than the reported losses in them due to the complexity and sometimes impossibility of collecting initial information for calculations. This may further lead to the bankruptcy of TSOs and the emergence of “orphan” electrical networks. Therefore, different methods for calculating standards for electricity losses in low-voltage networks were investigated in order to conduct a comparative analysis of the calculation accuracy of each of the approaches proposed in them.

To calculate the standards for electricity losses in 0.4 kV networks with known schemes, the same algorithms are used as for 6-10 kV networks, which are implemented using the average load method or the method of the number of hours of greatest power losses. At the same time, existing methods provide special assessment methods that determine the procedure for calculating loss standards in low-voltage networks (a method for assessing losses using generalized information about network circuits and loads, as well as a method for assessing losses using measured voltage loss values).

To carry out a numerical analysis of the accuracy of calculations, the losses of electrical energy are determined using the indicated methods based on the power supply circuit for household consumers of 0.4 kV. The design model of the 0.4 kV network is presented in the figure (where N is the load). Having a full amount of information about its configuration and mode allows you to calculate AW power losses using five methods. The calculation results are presented in table. 1.

Industrial energy No. i, 2010

Table 1

Calculation method	A W, kWh (%)	8 W, %
Method of characteristic seasonal days	11997,51 (3,837)
Average load method	12613,638 (4,034)
Method of number of hours of greatest power loss	12981,83 (4,152)
Loss estimation method using measured voltage loss values	8702,49 (2,783)
Method for estimating losses using generalized information about network circuits and loads	11867,21 (3,796)

The most reliable results are those obtained by element-by-element calculation of the 0.4 kV network using the method of characteristic seasonal days. However, it is necessary to have complete information about the network configuration, brands and cross-sections of wires, currents in phase and neutral wires, which is very difficult to obtain. From this point of view, it is simpler to calculate electricity losses using the average load method or the method of the number of hours of greatest power losses. But the use of these methods also requires a very labor-intensive element-by-element calculation of the network in the presence of initial information about currents and flows active power along lines, the collection of which is also practically impossible for many network organizations. Analysis of the loss results in the calculation model using the average load method and the method of the number of hours of greatest power losses shows an overestimation of electricity losses compared to the result obtained by the characteristic seasonal day method.

Using the method for estimating electricity losses based on the measured values ​​of voltage losses under the conditions of the network model under consideration leads to a significant underestimation of the standard for the losses under consideration. Voltage losses in 0.4 kV lines cannot be measured in full, and their reliability cannot be assessed when checking the calculation results. In this regard, the method is rather theoretical; it is not applicable for practical calculations, the results of which must be accepted by the regulatory body.

Therefore, according to the studies carried out, the most effective method seems to be for estimating electricity losses using generalized information about network patterns and loads. It is the least labor-intensive from the point of view of collecting enough initial circuit information for calculation. The results when used in the calculation model have a small discrepancy with the element-by-element calculation data, even at the level of determining losses in two feeders powered by one transformer substation. Taking into account real low-voltage circuits of existing TSOs, in which the number of 0.4 kV feeders reaches several tens and hundreds, the error in applying this method for estimating losses will be even less than at the level of the considered calculation model. Another advantage of this method is the ability to determine losses in an arbitrary number of power lines simultaneously. Its main disadvantages include the impossibility of a detailed analysis of losses in the 0.4 kV network and the development, based on the data obtained, of measures to reduce them. However, when approving standards for electricity losses as a whole for the network organization in the Ministry of Energy of the Russian Federation, this task is not the main one.

The positive experience of examining a number of network organizations makes it possible to analyze the dynamics of changes in the standards for electrical energy losses in the networks of the TGOs under consideration. Two organizations of the second group (conventionally designated TSO-1 and TSO-2) and six of the third group (TSO-3 - TSO-8) were chosen as objects of study. Results of calculation of their loss standards in 2008 - 2009. are presented in table. 2.

As a result, it was found that it is impossible to identify uniform trends in changes in loss standards in general for the considered

Table 2

Organization	Loss standards for TSOs in general, %
	in 2008	in 2009
TSO-1
TSO-2
TSO-3
TSO-4
TSO-5
TSO-6
TSO-7
TSO-8
Generally

ny organizations, therefore it is necessary to develop measures to reduce losses for each TCO separately.

Conclusions

1. The main directions for increasing the validity of rationing electricity losses in electrical networks are the development, creation and implementation of automated information and measurement systems for commercial metering for electricity markets, network organizations and enterprises.
2. The simplest and most effective, and sometimes the only one possible to use at this stage of development of network organizations, is the method of assessing losses using generalized information about network patterns and loads.
3. A detailed analysis of the results of calculating technical losses in 0.4 kV networks determines the effectiveness of developing measures to reduce them, therefore, it is necessary to continue research into methods for calculating losses in these networks.

References

1. Order calculation and justification of standards for technological losses of electricity during its transmission through electric networks (approved by order of the Ministry of Industry and Energy of Russia dated October 4, 2005 No. 267). - M.: CPTI and TO ORGRES, 2005.
2. Vukolov V. Yu., Papkov B. V. Features of calculating loss standards for electric grid organizations. Energy system: management, competition, education. - In the book: Sat. reports of the III international scientific and practical conference. T. 2. Ekaterinburg: USTU-UPI, 2008.

Electricity losses in electrical networks are inevitable, so it is important that they do not exceed an economically justified level. Exceeding technological consumption standards indicates problems that have arisen. To correct the situation, it is necessary to establish the causes of non-target costs and choose ways to reduce them. The information collected in this article describes many aspects of this difficult task.

Types and structure of losses

Losses mean the difference between the electricity supplied to consumers and the energy actually received by them. To normalize losses and calculate their actual value, the following classification was adopted:

• Technological factor. It directly depends on characteristic physical processes, and can change under the influence of the load component, semi-fixed costs, as well as climatic conditions.
• Operating costs auxiliary equipment and provision necessary conditions for the work of technical staff.
• Commercial component. This category includes errors in metering devices, as well as other factors causing under-metering of electricity.

Below is an average graph of losses for a typical electric company.

As can be seen from the graph highest expenses associated with transmission via overhead lines (power lines), this accounts for about 64% of the total losses. In second place is the corona effect (ionization of air near the overhead line wires and, as a consequence, the occurrence of discharge currents between them) – 17%.

Based on the presented graph, it can be stated that the largest percentage of non-targeted expenses falls on the technological factor.

Main causes of electricity losses

Having understood the structure, let's move on to the reasons that cause inappropriate expenditure in each of the categories listed above. Let's start with the components of the technological factor:

1. Load losses, they occur in power lines, equipment and various elements electrical networks. Such costs directly depend on the total load. This component includes:

• Losses in power lines are directly related to the current strength. That is why, when transmitting electricity over long distances, the principle of increasing it several times is used, which contributes to a proportional reduction in current and, accordingly, costs.
• Consumption in transformers of magnetic and electrical nature (). As an example, below is a table that shows cost data for substation voltage transformers in 10 kV networks.

Non-target consumption in other elements is not included in this category due to the complexity of such calculations and the insignificant amount of costs. For this, the following component is provided.

1. Category of semi-fixed expenses. It includes costs associated with the normal operation of electrical equipment, these include:

• Idle operation of power plants.
• Costs in equipment providing reactive load compensation.
• Other types of costs in various devices, whose characteristics do not depend on the load. Examples include power insulation, metering devices in 0.38 kV networks, measuring current transformers, surge limiters, etc.

Considering the last factor, the energy costs for melting ice should be taken into account.

Costs for supporting the operation of substations

This category includes the cost of electrical energy for the operation of auxiliary devices. Such equipment is necessary for the normal operation of the main units responsible for the conversion of electricity and its distribution. Costs are recorded using metering devices. Here is a list of the main consumers belonging to this category:

• ventilation and cooling systems for transformer equipment;
• heating and ventilation of the technological room, as well as internal lighting fixtures;
• lighting of areas adjacent to substations;
• battery charging equipment;
• operational circuits and monitoring and control systems;
• outdoor equipment heating systems, such as air circuit breaker control modules;
• various types of compressor equipment;
• auxiliary mechanisms;
• equipment for repair work, communication equipment, as well as other devices.

Commercial component

These costs mean the balance between absolute (actual) and technical losses. Ideally, such a difference should tend to zero, but in practice this is not realistic. This is primarily due to the characteristics of electricity meters and electricity meters installed at end consumers. It's about error. There are a number of specific measures to reduce losses of this type.

This component also includes errors in bills issued to consumers and theft of electricity. In the first case, a similar situation may arise for the following reasons:

• the contract for the supply of electricity contains incomplete or incorrect information about the consumer;
• incorrectly indicated tariff;
• lack of control over data from metering devices;
• errors related to previously adjusted accounts, etc.

As for theft, this problem occurs in all countries. As a rule, such illegal actions are carried out by unscrupulous household consumers. Note that sometimes incidents occur with enterprises, but such cases are quite rare, and therefore are not decisive. It is typical that the peak of thefts occurs during the cold season, and in those regions where there are problems with heat supply.

There are three methods of theft (understating meter readings):

1. Mechanical. This means appropriate intervention in the operation of the device. This can be slowing down the rotation of the disk by direct mechanical impact, changing the position of the electric meter by tilting it by 45° (for the same purpose). Sometimes a more barbaric method is used, namely, the seals are broken and the mechanism is unbalanced. An experienced specialist will instantly detect mechanical interference.
2. Electric. This could be like an illegal connection to overhead line by "throwing", a method of investing the phase of the load current, as well as the use special devices for full or partial compensation. In addition, there are options with bypass current circuit meter or switching phase and zero.
3. Magnetic. At this method A neodymium magnet is brought to the body of the induction meter.

Almost everything modern devices It will not be possible to “deceive” accounting using the methods described above. Moreover, such attempts to interfere can be recorded by the device and stored in memory, which will lead to dire consequences.

The concept of loss standard

This term means the establishment of economically sound criteria for non-target expenditure for a certain period. When standardizing, all components are taken into account. Each of them is carefully analyzed separately. As a result, calculations are made taking into account the actual (absolute) level of costs for the past period and an analysis of various opportunities that make it possible to realize the identified reserves to reduce losses. That is, the standards are not static, but are regularly revised.

The absolute level of costs in this case means the balance between the transferred electricity and technical (relative) losses. Technological loss standards are determined by appropriate calculations.

Who pays for lost electricity?

It all depends on the defining criteria. If we're talking about about technological factors and costs of supporting the operation of related equipment, then payment for losses is included in the tariffs for consumers.

The situation is completely different with the commercial component; if the established loss rate is exceeded, the entire economic load is considered an expense for the company that supplies electricity to consumers.

Ways to reduce losses in electrical networks

Costs can be reduced by optimizing the technical and commercial components. In the first case, the following measures should be taken:

• Optimization of the circuit and operating mode of the electrical network.
• Study of static stability and identification of powerful load nodes.
• Decline total power due to the reactive component. As a result, the share of active power will increase, which will have a positive impact on the fight against losses.
• Transformer load optimization.
• Equipment modernization.
• Various load balancing methods. For example, this can be done by introducing a multi-tariff payment system, in which per hour maximum load increased cost kW/h This will significantly reduce the consumption of electricity during certain periods of the day; as a result, the actual voltage will not “sag” below acceptable standards.

You can reduce your business costs by:

• regular search for unauthorized connections;
• creation or expansion of units exercising control;
• checking readings;
• automation of data collection and processing.

Methodology and example for calculating electricity losses

In practice, the following methods are used to determine losses:

• carrying out operational calculations;
• daily criterion;
• calculation of average loads;
• analysis of the greatest losses of transmitted power by day and hour;
• access to generalized data.

Full information on each of the methods presented above can be found in regulatory documents.

Finally, we give an example of calculating costs in power transformer TM 630-6-0.4. The calculation formula and its description are given below; it is suitable for most types of similar devices.

Calculation of losses in a power transformer

To understand the process, you should familiarize yourself with the main characteristics of TM 630-6-0.4.

Now let's move on to the calculation.

The amount of permanent electricity losses in the elements of the electrical network is

W"=(R k + R y + R xx) T on = R"T on, (8.1)

Where T on – turn-on time or operating time of electrical network elements throughout the year. For air and cable lines and transformers when performing design calculations is taken T on = 8760 h.

The total amount of electricity losses in the network is

W=W"+W". (8.2)

Let's consider ways to determine variable losses in the electrical network. Let for an element of an electrical network, for example an overhead line, having active resistance R, the annual load schedule is known. This graph is presented as a step graph by duration D t i of each load R i. (Fig. 8.1, A).

The energy transmitted during the year through the network element under consideration will be expressed as

W= . (8.3)

This energy represents the area of ​​the figure limited by the load diagram.

On the same graph we will construct a rectangle with a height equal to the greatest load R max , and area, equal area actual load schedule. The base of this rectangle will be time T max. This time is called duration of use of the heaviest load. During this time, when the network element operates with the highest load, the same electricity will be transmitted through it as when operating according to the actual annual load schedule. Average values T max for various industries are given in .

Power losses in the considered network element for each i-th time interval will be

R i =( S i/ U nom) 2 R=(P i/ U nom cos) 2 R, (8.4)

where cos is the load power factor.

In Fig. 8.1, b a stepwise graph of power losses is shown, constructed using expression (8.4). The area of ​​this graph is equal to the annual variable electricity losses in the network element under consideration

a) b)

Rice. 8.1. Duration Load Graphs for Timing

T max ( A) and time max ( b)

W"= . (8.5)

By analogy with Fig. 8.1, A construct a rectangle with a height equal to the greatest losses R max , and an area equal to the area of ​​the actual graph of electricity losses. The base of this rectangle will be time max. This time is called time of greatest power loss. During this time, when the network element operates with the highest load, the electricity losses in it will be the same as when operating according to the actual annual load schedule.

Communication between T max and max are approximately established by the empirical dependence

max =(0.124+ T max 10 -4) 2 8760. (8.6)

In the long-term design of electrical networks, the consumer load schedule is, as a rule, unknown. Only the largest is known with a certain degree of certainty. design load R max.

For typical consumers, the reference literature provides values T max. In this case, the variable annual electricity losses in an electrical network element are determined by the expression

W"=P max max , (8.7)

where max is calculated using expression (8.6).

Security questions to section 8

1. Explain the terms “fixed losses” and “variable losses” of electricity.

2. Name the components of permanent losses.

3. What is the number of hours of use of the heaviest load?

4. What is the number of hours of greatest power loss?

5. How are variable energy losses calculated during design?

electrical networks?

Line Length (m) / Cable Material:		Copper Aluminum
Cable cross-section (mm?):	0.5 mm? 0.75 mm? 1.0 mm? 1.5 mm? 2.5 mm? 4.0 mm? 6.0 mm? 10.0 mm? 16.0 mm? 25.0 mm? 35.0 mm? 50.0 mm? 70.0 mm? 95.0 mm? 120 mm?
Load power (W) or current (A):
Mains voltage (V):		Power	1 phase
Power factor (cos?):		Current	3 phase
Cable temperature (°C):

When designing electrical networks and systems with low currents, calculations of voltage losses in cables and wires are often required. These calculations are necessary in order to select the most optimal cable. At wrong choice conductor, the power supply system will very quickly fail or will not start at all. To avoid possible errors, it is recommended to use an online voltage loss calculator. The data obtained using the calculator will provide stable and safe work lines and networks.

Causes of energy loss during electricity transmission

Significant losses occur as a result of excessive dispersion. Due to excess heat, the cable can become very hot, especially under heavy loads and incorrect calculations of electricity losses. Excessive heat causes damage to the insulation, creating real threat health and life of people.

Electricity losses often occur due to too long cable lines, when high power loads. In case of prolonged use, electricity costs increase significantly. Incorrect calculations can cause equipment malfunctions, for example, burglar alarm. Voltage loss in a cable becomes important when the equipment power supply has low voltage permanent or AC, rated from 12 to 48V.

How to calculate voltage loss

Avoid possible problems a voltage loss calculator that works in online mode. The source data table contains data on the length of the cable, its cross-section and the material from which it is made. For calculations, information about load power, voltage and current will be required. In addition, the power factor and temperature characteristics of the cable are taken into account. After pressing the button, data appears on energy losses as a percentage, conductor resistance indicators, reactive power and the voltage experienced by the load.

The basic calculation formula is the following: ΔU=IхRL, in which ΔU means the voltage loss on the settlement line, I is the consumed current, determined primarily by the consumer parameters. RL reflects the resistance of the cable, depending on its length and cross-sectional area. It is the latter value that plays a decisive role in the loss of power in wires and cables.

Opportunities for reducing losses

The main way to reduce losses in a cable is to increase its cross-sectional area. In addition, you can reduce the length of the conductor and reduce the load. However, the last two methods cannot always be used, due to technical reasons. Therefore, in many cases the only option What remains is a reduction in cable resistance due to an increase in cross-section.

A significant disadvantage of a large cross-section is considered to be noticeable growth material costs. The difference becomes noticeable when cable systems stretch over long distances. Therefore, at the design stage, you must immediately select a cable with the required cross-section, for which you will need to calculate the power loss using a calculator. This program has great value when drawing up projects for electrical installation work, since manual calculations take a lot of time, and in mode online calculator The calculation takes literally a few seconds.