How to calculate power loss. Causes of power loss over long distances

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

Types and structure of losses

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

• technological factor. It directly depends on the 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 ensuring necessary conditions for the work of technical staff.
• commercial component. This category includes errors in metering devices, as well as other factors that cause underestimation of electricity.

Below is an average loss graph for a typical power company.

As seen from the graph the biggest expenses associated with overhead transmission lines (TL), this is about 64% of total number losses. In second place is the effect of corona (ionization of air near the wires of overhead lines and, as a result, 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.

The main causes of electricity losses

Having dealt with the structure, let's move on to the reasons that cause misuse 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 power grids. Such costs directly depend on the total load. This component includes:

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

Non-target expenditure 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 the 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 arresters, etc.

Considering the last factor, the cost of electricity for melting ice should be taken into account.

Substation support costs

This category includes costs electrical energy on the operation of assistive devices. Such equipment is necessary for the normal operation of the main units responsible for the conversion of electricity and its distribution. Cost fixing is carried out by 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 devices;
• lighting of territories adjacent to substations;
• battery charging equipment;
• operational chains and control and management systems;
• heating systems for outdoor equipment, such as air circuit breaker control modules;
• various types of compressor equipment;
• auxiliary mechanisms;
• equipment for repair work, communications equipment, and other devices.

Commercial component

These costs mean the balance between absolute (actual) and technical losses. Ideally, this difference should tend to zero, but in practice this is not realistic. First of all, this is due to the peculiarities of metering devices for supplied electricity 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 invoices issued to consumers and theft of electricity. In the first case, such a 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 the data of metering devices;
• errors related to previously corrected invoices, etc.

As for theft, this problem occurs in all countries. As a rule, unscrupulous household consumers are engaged in such illegal actions. Note that sometimes there are incidents with enterprises, but such cases are quite rare, therefore they are not decisive. Characteristically, the peak of theft falls on the cold season, and in those regions where there are problems with heat supply.

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

1. Mechanical. It means appropriate intervention in the operation of the device. This can be slowing down the rotation of the disk by direct mechanical action, 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. Experienced specialist immediately detect mechanical interference.
2. Electric. This can be as illegal connection to the overhead line by "surge", a method of investing the phase of the load current, as well as the use of special devices for its full or partial compensation. In addition, there are options with shunting the current circuit of the meter or switching phase and zero.
3. Magnetic. At this method a neodymium magnet is brought to the body of the induction meter.

Almost all modern appliances Accounting "deceive" the above methods will not succeed. Moreover, such intervention attempts can be recorded by the device and stored in memory, which will lead to sad consequences.

The concept of loss rate

This term refers to the establishment of economically sound criteria for non-targeted expenditure for a certain period. When normalizing, 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 allow realizing the identified reserves to reduce losses. That is, the standards are not static, but are regularly reviewed.

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

Who pays for electricity losses?

It all depends on the defining criteria. When it comes to technological factors and the costs of supporting the work related equipment, then the payment for losses is included in the tariffs for consumers.

The situation is completely different with the commercial component, if the laid down rate of losses is exceeded, the entire economic burden is considered to be the expenses of the company that supplies electricity to consumers.

Ways to reduce losses in electrical networks

You can reduce costs by optimizing the technical and commercial components. In the first case, the following steps should be taken:

• Optimization of the scheme and mode of operation of the power grid.
• Study of static stability and selection of powerful load nodes.
• Reducing the total power due to the reactive component. As a result, the share of active power will increase, which will positively affect the fight against losses.
• Load optimization of transformers.
• Modernization of equipment.
• Various load balancing methods. For example, this can be done by introducing a multi-tariff payment system, in which the cost of kWh is increased during peak hours. This will significantly allow the consumption of electricity during certain periods of the day, as a result, the actual voltage will not “sag” below the permissible norms.

You can reduce business costs in the following ways:

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

Methodology and example for calculating electricity losses

In practice, apply the following methods to determine losses:

• carrying out operational calculations;
• daily criterion;
• calculation of average loads;
• analysis of the largest losses of transmitted power in the context of days-hours;
• access to aggregated data.

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

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

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.

Losses of electricity in electrical networks happen quite often and there are reasons for this. Losses in power networks are the differences between the transmitted electrical energy on power lines to the accounted, consumed energy of the consumer. Consider what are the measures to reduce losses.

Power Loss in Power Line: Distance from Power Plant

Accounting and payment of all types of losses is regulated by law. When energy is transported over long distances from the producer to the consumer, part of the electricity is lost. This happens for various reasons, one of which is the level of voltage that an ordinary consumer consumes (220 or 380 V). If such electricity is transported directly from the generators of the stations, then it is necessary to lay electrical networks with a diameter of the electrical wire that will provide everyone with the required electric current. Electric wires will be with a very large cross section.

They will not be able to be placed on power lines, due to the unthinkable gravity, laying in the ground over long distances will be very expensive.

In order to eliminate this factor in power networks, they use high voltage lines transmission of electricity. Transmitting energy with such an electrical voltage, it is also wasted many times over from poor-quality contact of electrical conductors, which increase their resistance from year to year. Losses increase with increasing air humidity - the leakage current on the insulators and on the corona increases. Losses in cables also increase with a reduction in the parameters of the insulation of electrical wires. Sent by the supplier of electricity to the supply organization.

It should accordingly bring the parameters to required indicators when transferring:

1. Convert the product that was received into an electrical voltage of 6-10 kV.
2. Distribute cables at the points of reception.
3. Then re-convert to electrical voltage in the wires of 0.4 kV.

Again, losses, transformation during the operation of electrical transformers 6-10 kV and 0.4 kV. An ordinary consumer is supplied with energy in the required voltage - 380-220 V. Transformers have their own efficiency and are calculated for a certain load. If you overdo it with power, or vice versa, if it is less than the calculated one, the losses in the power networks 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 to 220 V. If consumers take more energy than the power indicated in the transformer passport, it either breaks down or cannot provide the required output parameters. As a result of a decrease in the electrical voltage of the mains electrical devices operate in violation of the passport regime and, therefore, consumption increases.

What determines the voltage loss in the wires

The consumer took his 220 or 380 V on the electricity meter. Now the energy that will be lost can be transferred to the end consumer.

Consists of:

1. Losses on heating of electric wires when increased consumption due to calculations.
2. Poor electrical contact in electrical appliances switching power supply.
3. Capacitive and inductive nature of the electrical load.

Also included is the use of old lighting fixtures, refrigeration equipment and other obsolete technical devices.

Comprehensive measures to reduce electricity losses

Consider measures to reduce electrical energy losses in the cottage and the apartment building.

Necessary:

1. To fight, it is necessary to use electrical conductors corresponding to the load. Today, in power grids, it is necessary to monitor the compliance of the parameters of the electrical wires and the power that is consumed. In a situation where it is impossible to adjust these parameters and introduce them 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.
2. Poor electrical contact: in circuit breakers, this is the use of innovative designs with good non-oxidizing electrical contacts. Any oxide increases resistance. In starters - the same technique. Switches - on/off system should use a metal that is moisture resistant and resistant to high temperature regime. The contact depends on the qualitative pressing of the pole to the plus.
3. reactive load. All electrical appliances that are not incandescent bulbs, electric hotplates the old model 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, such a phenomenon as magnetic induction, which did not allow the current to flow, helps it flow and adds part of the electricity to the power grid, which is harmful to public electricity networks. A special process is developing, which is called eddy electric currents, they distort the norm of meter readings and make negative changes in the parameters of the energy that is supplied. The same happens with capacitive electrical loads. The 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. The use of old lighting systems (incandescent lamps). Their efficiency has a maximum of 3-5%. The remaining 95% is spent on heating the filament and, as a result, on heating environment and radiation that a person does not perceive. Therefore, it is not rational to improve here. Other types of light supply appeared - fluorescent bulbs, LEDs, which have become actively used today. The efficiency of fluorescent lamps reaches 7%, and for LEDs the percentage is close to 20. The use of LEDs allows you to save right now and during operation due to durability - cost compensation up to 50,000 hours.

It is also impossible not to say that you can reduce the loss of electricity in the house by installing a voltage stabilizer. According to the town hall, you can find it in specialized companies.

How to calculate electricity losses: conditions

The easiest way to calculate the losses in the power grid, 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 found, usually different electrical wires are used to supply buildings and structures. In such a situation, in order to obtain accurate results, it is necessary to separately calculate 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 appliances for metering the consumed electricity are placed in the electrical circuit after such special equipment.

Important:

1. The calculation of energy losses in a transformer is carried out on the basis of the technical documents of such a device, where all the parameters you need will be indicated.
2. It must be said that any calculations are performed in order to determine the magnitude of the maximum loss during current transfer.
3. When making calculations, it must be taken into account that the power supply of a warehouse, manufacturing plant or other facility is sufficient to provide all the energy consumers connected to it, that is, the system can operate without overvoltage even at maximum load, at each included facility.

The amount of allocated electrical power can be found in the contract concluded with the energy supplier. The amount of losses always depends on the power of the mains, on its consumption through the potter. The more electricity consumed by objects, the higher the losses.

Technical losses of electricity in networks

Technical energy losses are losses that are caused by physical processes transportation, distribution and transformation of electricity are identified through calculations. The formula by which the calculation is performed: P=I*U.

1. Power equals current multiplied by voltage.
2. By increasing the voltage during the transmission of energy in power networks, it is possible to reduce the current by several times, which will make it possible to get by with 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 is commercial power loss

Commercial energy losses are electrical losses, which are defined as the difference between absolute and technological losses.

Need to know:

1. Ideally, commercial power losses in the power grid should be zero.
2. It is obvious, however, that in reality the supply to the power grid, useful supply and technical losses are determined with errors.
3. In fact, their differences are the structural elements of commercial power losses.

They should, as far as possible, be reduced to minimum value by taking certain measures. If this is not possible, it is necessary to amend the meter readings, they compensate for the systematic errors in the measurements of electrical energy.

Possible losses of electricity in electrical networks (video)

Losses of electrical energy in the power grid lead to additional costs. Therefore, it is important to control them.

When transmitting electrical energy from generators of power plants to the consumer, about 12-18% of all generated electricity is lost in the conductors of overhead and cable lines, as well as in windings and steel cores of power transformers.

When designing, it is necessary to strive to reduce electricity losses in all parts of the power system, since electricity losses lead to an increase in the capacity of power plants, which in turn affects the cost of electricity.

In networks up to 10 kV, power losses are mainly due to the heating of the wires from the action of the current.

Line power loss.

Active power losses (kW) and reactive power losses (kvar) can be found using the following formulas:

where Icalc- rated current of this section of the line, A;

Rl– active resistance of the line, Ohm.

Power losses in transformers.

Power losses in power transformers consist of losses that do not depend on the load and depend on the load. Active power losses (kW) in a transformer can be determined by the following formula:

Active power losses in the transformer

where ?Rst– active power losses in the steel of the transformer at rated voltage. They depend only on the power of the transformer and the voltage applied to the primary winding of the transformer. ?Rst equate ?Рх;

?Рх- no-load losses of the transformer;

?Rob- losses in the windings at the rated load of the transformer, kW; ?Rob equate ?Рк.

?Рк– short circuit losses;

?=S/Snom– the load factor of the transformer is equal to the ratio of the actual load of the transformer to its rated power;

The reactive power loss of a transformer (kvar) can be determined by the following formula:

where ? Qst– losses of reactive power for magnetization, kvar. ? Qst equate ? Qx.

? Qx- the magnetizing power of the idling of the transformer;

? Qrac- loss of reactive power dissipation in the transformer at rated load.

Values ? Rst( ? Rx) and ? Rob( ? Rk) listings in the catalogs of manufacturers of power transformers. Values ? Qst( ? Qx) and ?Qrac are determined by the catalog data from the following expressions:

where IX- no-load current of the transformer,%;

Uk– short circuit voltage, %;

Inom- rated current of the transformer, A;

Xtr- reactance of the transformer;

Snom- rated power of the transformer, kVA.

Loss of electricity.

Based on the power losses, the power losses can be calculated. Here you should be careful. It is impossible to calculate the power loss by multiplying the power loss at any particular load by the number of hours of operation of the line. This should not be done, because during the day or season the consumed load changes and thus we get an unreasonably high value.

Time of maximum loss ? - the conditional number of hours during which the maximum current flowing in the line creates energy losses equal to the actual energy losses per year.

Time to use the maximum load or time to use the maximum Tmax they call the conditional number of hours during which the line, working at maximum load, could transfer as much energy to the consumer in a year as when working on a real variable schedule. Let be W(kW*h) - energy transmitted through the line for a certain period of time, Rmax(kW) -maximum load, then the time of using the maximum load:

Tmax=W/Pmax

Based on statistical data for individual groups of electrical receivers, the following values ​​were obtained Tmax:

• For indoor lighting - 1500-2000 hours;
• Outdoor lighting - 2000-3000 hours;
• Single-shift industrial enterprise - 2000-2500 hours;
• Two-shift - 3000-4500 hours;
• Three-shift - 3000-7000 hours;

Loss time ? can be found from the schedule, knowing Tmax and power factor.

Energy losses in the transformer:

Energy losses in the transformer

where ? Watr– total loss of active energy (kWh) in the transformer;

? Wrtp is the total loss of reactive energy (kvar*h) in the transformer.

the complexity and laboriousness of calculating loss standards (especially in distribution networks of 0.4 kV), the practical impossibility of a reliable assessment of their accuracy;

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

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

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

The calculation of loss standards in 0.4 kV networks is one of the most laborious. This is due to the following features:

heterogeneity of initial circuit information and its low reliability;

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

the dynamics of changes in circuit and especially regime parameters;

execution of sections of networks with a different number of phases;

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

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

Examination of 10 TCO Nizhny Novgorod region, performing calculations of loss standards, their examination and approval allow structuring the created TSS into the following groups:

1. successors of AO-energos;
2. created on the basis of the services of the chief power engineer of an industrial enterprise in accordance with the restrictions of the antimonopoly law;
3. created to ensure the operation of electrical equipment that turned out to be "ownerless" during the implementation of market reform in the field of industrial and agricultural production.

The emergence of organizations - legal successors of the previously existing AO-Energos - is associated with the restructuring and liquidation of RAO "UES of Russia". Calculation and approval of loss standards for TSS of this group require minimal intervention of third-party researchers, since this task is not new for them: there is a rather long history, personnel with extensive experience in calculations, and maximum information security. Methodical materials focused mainly on the features of the operation of this particular group of TCO.

An analysis of the problems associated with the determination of loss standards for enterprises of the second group shows that today there is an acute shortage of personnel who are ready to apply the existing methodology for calculating loss standards that is not adapted to the actual operating conditions of such TSOs. In this case, it is advisable to involve external specialized companies for calculations and approval of loss standards. This eliminates the need for expensive special certified software available from third-party researchers. If, however, we consider the task of approving a tariff for electricity transport services through factory networks as a more general one, in which the calculation of the loss standard is only 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 a change in the form of maintenance of electrical equipment .

When calculating losses in 0.4 kV networks of such TSOs, the most acute problem is the division of a single 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 forms. Taking into account the real distribution of connection points for third-party consumers, the volume of productive supply by voltage levels and the complexity of calculating losses in 0.4 kV networks, in almost all cases it is advisable to completely attribute these networks to the technological part.

TSOs belonging to the third group are formed as a result of forced measures taken by the state and private business to eliminate an 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 a voltage of 10-6-0.4 kV) was abandoned by the previous owners. Currently technical condition many of these electrical installations can be described as unsatisfactory. However, their withdrawal from work is impossible due to social significance. With this in mind, the regions are implementing a program for the restoration of dilapidated and "ownerless" networks, which is financed, including centrally, from the federal budget. In most cases, electrical equipment is taken on the balance sheet by local governments, which solve the problem of ensuring its normal functioning. Based on the experience of the Nizhny Novgorod region, it can be concluded that the main direction of using this equipment is to lease it to state and private specialized companies.

Due to the dispersal of networks of such TSOs in different administrative regions, to solve the problems of transmission and distribution of electricity, ensure the operability of electrical networks (installation, adjustment, repair and Maintenance electrical equipment and means of protecting electrical networks) there are two ways: creating your own maintenance and repair service (which, due to the coverage of a large area, will lead to an increase in the duration of equipment maintenance) or concluding maintenance contracts with AO-energo services. At the same time, efficiency will be ensured, but the expediency of the existence of organizations of this type loses its meaning. Currently, TSOs of the third group are carrying out work on the installation of electricity metering units, financed under the regional program for the restoration of dilapidated networks and from other sources. The issues of organizing a system for collecting and processing information about the readings of electricity meters with the involvement of specialized organizations are being addressed. However, the high cost and volume necessary work, as well as the existing contradictions between the participants in the process of forming an electricity metering system, will require a long time for their full completion.

Under the current system of tariff formation for the transport of electric energy, the calculation is based on 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 the 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 are:

there are practically no passport data for electrical equipment;

there are no single-line diagrams of electrical networks, support diagrams of overhead power lines (BJI) and diagrams of routes 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 TSOs under consideration and are elements of connections of other TSOs.

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

As an example, let's consider the features of calculating the electricity loss standards for an organization (conditionally called TCO-energy), whose electrical equipment is dispersed over the territory of 17 districts of the Nizhny Novgorod region. The sources of initial information about the electrical equipment and operating modes of TSO-energo by the time the survey began were lease agreements for electrical equipment and facilities, contracts for technical and operational maintenance concluded by its administration with branches of OAO Nizhnovenergo in the field and with a guaranteeing supplier of electricity in the region. Due to the impossibility at the initial stage of functioning of TCO-energo as an electric grid organization to account for the transported electrical energy using electric meters, the volumes of transmitted electricity were determined by calculation.

During the inspection of electrical installations, it was obtained Additional Information about 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 the analysis of the obtained data, the 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), obtained average values ​​of such parameters as number of feeders 0.4 kV per one transformer substation (2.3); cross-section of the head section of the feeder line of the power transmission line 0.4 kV (38.5 mm 2), cross-sections of cable (50 mm 2) and air (35 mm ") power transmission lines 6 kV.

Information about 0.4 kV electrical networks of all 17 districts is structured on the basis of extrapolation of the results of the analysis of the support circuits of electrical networks for a sample of two. According to the expert opinion, these areas are typical for TSO-energo, and extrapolation of the sample results does not distort the overall picture of the network configuration of the organization as a whole. Below are the obtained values ​​of the power loss standard AW Hn3, thousand kWh (%), for a regulation period of 1 year, for networks of 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 this situation, taking into account the state of electrical installations of most TSOs, the most

more effective, and sometimes the only one possible for calculating losses in 0.4 kV networks, was the method of estimating losses from generalized information about circuits and network loads. However, according to the latest edition, its use is possible only when the low voltage network is powered by at least 100 TP, which significantly limits the application of the method for calculating losses in TSO networks. Here, a situation is possible when the standard of electricity losses in low-voltage networks obtained by calculation and justified by the availability 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. In the future, this may lead to the bankruptcy of TSOs and the emergence of “ownerless” electrical networks. Therefore, different methods for calculating the standards for electricity losses in low-voltage networks were investigated in order to conduct a comparative analysis of the accuracy of calculating each of the approaches proposed in the approaches.

To calculate the power loss standards in 0.4 kV networks with their 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 the greatest power losses. At the same time, existing methods provide for special evaluation methods that determine the procedure for calculating loss standards in low-voltage networks (a method for estimating losses based on generalized information about network circuits and loads, as well as a method for estimating losses using measured values ​​of voltage losses).

To carry out a numerical analysis of the accuracy of calculations by these methods, the losses of electrical energy were determined based on the power supply scheme for household consumers of 0.4 kV. The design model of the 0.4 kV network is shown in the figure (where H is the load). Having full information about its configuration and mode allows you to calculate the power loss AW by five methods. The calculation results are presented in Table. one.

Industrial Energy №i, 2010

Table 1

The most reliable results are 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 full information about the configuration of the network, brands and 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 power losses by the method of average loads or by the method of the number of hours of the greatest power losses. But the use of these methods also requires a very time-consuming element-by-element calculation of the network in the presence of initial information about the currents and active power flows along the lines, the collection of which is also practically impossible for many network organizations. Analysis of the results of losses in the calculation model by applying the method of average loads and the method of the number of hours of the greatest power losses shows an overestimation of electricity losses compared to the result obtained by the method of characteristic seasonal days.

The use of the method for estimating electricity losses by measured values ​​of voltage losses under the conditions of the considered network model leads to a significant underestimation of the standard of the considered losses. 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 conducted research, the most effective method seems to be the method of estimating electricity losses based on generalized information about the schemes and loads of the network. It is the least laborious in terms of collecting the amount of initial circuit information sufficient for the calculation. The results when it is used in the calculation model have a small discrepancy with the data of the element-by-element calculation, even at the level of determining losses in two feeders powered by one transformer substation. Taking into account the real low-voltage circuits of existing TSS, 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 transmission lines simultaneously. Its main disadvantages include the impossibility of a detailed analysis of losses in the 0.4 kV network and the development of measures to reduce them based on the data obtained. However, when approving the standards for electricity losses in general for a grid 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 grid organizations allows us to analyze the dynamics of changes in the standards for electrical energy losses in the networks of the TSOs under consideration. Two organizations of the second group (conditionally designated TCO-1 and TCO-2) and six organizations of the third group (TCO-3 - TCO-8) were chosen as the objects of study. The results of the calculation of their loss standards in 2008 - 2009. are presented in table. 2.

As a result, it was found that it is impossible to single out common trends in changes in loss standards in general for consideration.

table 2

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

findings

1. The main directions of increasing the validity of regulation of electricity losses in electrical networks are the development, creation and implementation of automated information and measurement systems for commercial accounting for electricity markets, grid organizations and enterprises.
2. The simplest and most effective, and sometimes the only one possible for use at this stage in the development of network organizations, is a method for estimating losses based on generalized information about network schemes 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, so it is necessary to continue research on methods for calculating losses in these networks.

Bibliography

1. Order calculation and justification of the 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.: TISC and TO ORGRES, 2005.
2. Vukolov V. Yu., Papkov B. V. Features of the calculation of loss standards for power grid organizations. Energy system: management, competition, education. - In the book: Sat. reports of the III international scientific-practical conference. T. 2. Ekaterinburg: USTU-UPI, 2008.

During the design of 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 cable with the most optimal. At wrong choice conductor, the power supply system will fail very quickly or not start at all. To avoid possible errors, it is recommended to use the online voltage loss calculator. The data obtained using the calculator will provide a stable and safe work lines and networks.

Causes of energy loss in the transmission of electricity

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

Losses of electricity often occur due to too long cable lines, with high power loads. In the case of prolonged use, the cost of paying for electricity increases significantly. Incorrect calculations can cause equipment malfunctions, for example, burglar alarm. Voltage losses in the cable acquire importance when the power supply of the equipment has low DC voltage or alternating current, rated from 12 to 48V.

How to Calculate Voltage Loss

To avoid possible problems the online voltage loss calculator will help. Data on the length of the cable, its cross section and the material from which it is made are placed in the table of initial data. For calculations, information about the 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 on energy losses in percent, indicators of conductor resistance, reactive power and voltage experienced by the load appear.

The basic calculation formula is the following: ΔU=IxRL, in which ΔU means the voltage loss on the calculated line, I is the consumed current, determined mainly by the parameters of the consumer. RL reflects the resistance of the cable, depending on its length and cross-sectional area. It is the last meaning decisive role power loss in wires and cables.

Opportunities to reduce losses

The main way to reduce cable losses is to increase its cross-sectional area. In addition, it is possible to shorten the conductor length and reduce the load. However, the last two methods cannot always be used, due to technical reasons. Therefore, in many cases, the only option is to reduce the resistance of the cable by increasing the cross section.

A significant disadvantage of a large cross section is a noticeable increase in 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 desired section, for which you will need to calculate the power loss using a calculator. This program has great importance when preparing projects for electric installation work, since manual calculations take a lot of time, and in the mode online calculator The calculation takes just a few seconds.