Electricity stealing identification method based on electrical parameters of power grid

Abstract

The invention discloses an electricity larceny identification method based on power grid electrical parameters, relates to a power grid electricity larceny identification method, and aims to solve the problems that an existing electricity larceny prevention method is limited by electricity larceny types and is poor in accuracy and universality. The method comprises the following steps: obtaining a branch resistance calculation value by using metering data of metering equipment on a branch; obtaining a branch resistance true value by using the power flow data of the branch; comparing the branch resistance calculation value with the branch resistance true value to generate a comparison result; and according to a comparison result, judging whether the branch is subjected to electricity stealing or not. The method has the advantages that the electricity stealing identification method is not limited by electricity stealing types, and the universality of electricity stealing prevention is improved; meanwhile, the branch circuit where electricity stealing happens and the electricity stealing time can be determined, and the accuracy of electricity stealing prevention is greatly improved.

Description

Technical Field

[0001] The invention relates to a method for identifying power grid electricity theft. Background Art

[0002] The main reason for the existence of high management line loss in the power transmission and distribution network is that the theft of electricity cannot be effectively stopped. The theft of electricity refers to the illegal behavior of artificially using some technical means to make the electricity metering equipment under-meter or even not meter electricity, thereby achieving the purpose of paying less or not paying electricity bills; with the continuous progress of social sciences and the continuous updating of the power transmission and distribution network, how to reduce line loss has become the main problem currently faced; while the theft of electricity is the main factor affecting the difficulty in reducing the management line loss, it also harms the normal economic operation, slows down the upgrading and transformation of the power grid, and has attracted widespread attention from all walks of life. The dazzling array of theft of electricity can be roughly divided into two categories: tampering with the metering equipment and intact metering equipment. The normal transmission process of electric energy is that after the electric energy passes through the transmission and distribution network, it is recorded by the metering equipment and transmitted to the electricity user to meet the electricity demand; however, those users who want to achieve illegal electricity use steal electricity by modifying the metering device or choosing to directly bypass the metering device. Among them, the direct modification of the metering device to achieve the theft of electricity is achieved by changing the electrical parameters such as voltage, current, power, and phase angle. This situation mainly includes undervoltage method, undercurrent method, differential expansion method, phase shift method, etc. The means of stealing electricity without directly changing the electricity metering device are to privately connect to the power line, illegally increase the power capacity, bribe relevant personnel to falsely report the power, etc.

[0003] Common anti-theft methods for component power theft include: improving meter boxes and meter cabinets, adding special seals to the end of meters; adding anti-theft caps to transformer low-voltage pipes; using anti-theft meter boxes to enhance line management in front of meters, shutting off transformer low-voltage outlets and lines in front of meters; using bidirectional meters or check meters to prevent users from reversing their meters; replacing low-voltage lines with insulated wires or cables in areas where there is serious disorderly hanging without permission; promoting the use of current transformer bushings in distribution transformers to prevent users from stealing electricity by destroying current transformers; using voltage transformer circuits of metering equipment in conjunction with pressure loss recorders.

[0004] As the methods of electricity theft become more and more secretive, the anti-electricity theft mode has gradually developed from the existing anti-electrical theft mode to today's anti-electricity theft mode using the power information collection system. The development of anti-electricity theft technology is inseparable from the promotion of power system information collection. Some electricity theft identification methods based on real-time monitoring data of electricity users have been popularized. The method of comparing real-time data with historical data can be used to find out users who are suspected of stealing electricity. In addition, in order to prevent collusion between internal and external thefts, the power supply company has strengthened the management of employees, implemented an irregular rotation system for meter readers, and strengthened internal prevention measures.

[0005] Although some of the anti-electricity theft modes being implemented can identify some electricity theft behaviors, there are still certain limitations. The methods for preventing electricity theft from components are mostly one-to-one prevention methods, which are not scalable and practical. In the electricity theft identification methods based on the real-time monitoring data of electricity users, voltage, current or power are used by most people as electrical reference quantities for electricity theft judgment. As we all know, these reference quantities often change with changes in the operation of the power grid. Once the electricity theft behavior is hidden in it, it is difficult for us to determine whether the change in the electrical reference quantity is a normal change or a change caused by electricity theft. Therefore, the existing anti-electricity theft methods have poor accuracy and poor universality, and cannot meet the safe operation of the power system. Summary of the invention

[0006] The purpose of the present invention is to solve the problems that the existing anti-electricity theft methods are limited by the types of electricity theft, have poor accuracy and poor universality, and propose a method for identifying electricity theft based on electrical parameters of the power grid.

[0007] The invention discloses a method for identifying electricity theft based on electrical parameters of a power grid, comprising the following steps:

[0008] Step 1: Use the measurement data of the branch metering equipment to obtain the calculated value of branch resistance R 计 ;

[0009] Step 2: Use the branch flow data to obtain the true value of the branch resistance R 真 ;

[0010] Step 3: Compare the calculated branch resistance value obtained in step 1 with the actual branch resistance value obtained in step 2 to generate a comparison result ΔR; the calculation formula of the comparison result ΔR is:

[0011] ΔR=R 计 -R 真

[0012] Step 4: The criteria for electricity theft are:

[0013]

[0014] It is determined whether electricity theft occurs in the branch circuit according to the electricity theft criterion.

[0015] Furthermore, before using the metering data of the metering device on the branch line for calculation, the metering data of the metering device is corrected;

[0016] The specific method for correcting the metering data of the metering equipment is:

[0017] Step 1: Collect the electrical parameter data of the branch n times within the time T. The collected electrical parameter data are: X1 , X 2 , ...X n ;

[0018] Step 2: The variance D(X i ) as the criterion for whether the branch is in a steady state:

[0019] The specific judgment formula is:

[0020]

[0021] Where, σ is the electrical parameter data error; X i is the i-th electrical parameter data collected;

[0022] If the n electrical parameter data collected within the time T all meet the steady-state requirements of the branch, then execute step 3; otherwise, shorten the time T and return to execute step 1;

[0023] Step 3: Divide time T into m time periods and calculate the average value of the data in each time period k∈[1,m], where k is the kth time period;

[0024] when and The following relationship is satisfied;

[0025]

[0026] in, is the average value of n electrical parameter data;

[0027] Then, execute step 4; otherwise, shorten the time T and return to execute step 1;

[0028] Step 4: Collect the electrical parameter data X i Make corrections to obtain corrected electrical parameter data

[0029] The corrected electrical parameter data The calculation formula is:

[0030]

[0031] Among them, γ i is the correction coefficient of the i-th correction data;

[0032] Complete the correction of the measurement data of the measuring equipment.

[0033] Furthermore, in step 2, the variance D(X i ) is solved as follows:

[0034] First, find the average value of n electrical parameter data The average The calculation formula is:

[0035]

[0036] Finally, using the average value And the collected electrical parameter data X i Perform variance calculations;

[0037] The variance of n data D(X i ) is calculated as:

[0038]

[0039] Furthermore, the value range of the electrical parameter data error σ in step 2 is: 2%≤σ≤5%.

[0040] Furthermore, the correction coefficient γ of the i-th correction data in step 4 is i The calculation formula is:

[0041]

[0042] Furthermore, the specific method for obtaining the calculated value of the branch resistance in step 1 is:

[0043] Step 1. Obtain branch power according to the metering data of the metering equipment and the power consumption time; the specific calculation formula is:

[0044]

[0045] Where W is the metering data of the metering equipment; t is the electricity consumption time; P 支 is the branch power;

[0046] Step 12: According to the branch power obtained in step 11 and the rated voltage of the branch, obtain the calculated value of the branch resistance; the specific calculation formula is:

[0047]

[0048] Among them, R 计 is the calculated value of branch resistance; U 额 is the rated voltage of the branch.

[0049] Furthermore, the specific method for obtaining the true value of the branch resistance in step 2 is:

[0050] According to the branch voltage and branch current in the power flow data, the true value of the branch resistance is obtained; the specific calculation formula is:

[0051]

[0052] Among them, R 真 is the true value of branch resistance; U 支 is the branch voltage in the power flow data; I 支 is the branch current in the power flow data.

[0053] Furthermore, the calculation formula for generating the comparison result in step 3 is replaced by:

[0054] In addition, the specific method for determining whether electricity theft occurs in the branch circuit in step 4 is:

[0055] It is determined whether the comparison result is greater than the error threshold. If so, it indicates that electricity theft exists in the branch; otherwise, it indicates that electricity theft does not exist in the branch.

[0056] Furthermore, the error threshold is 2%.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] The present invention uses the characteristic that the metering device measures power inaccurately but the voltage is relatively accurate when electricity is stolen, removes the reactance affected by the user-side power electronic switch in the impedance, and finally selects the line resistance value as the electrical parameter of the electricity theft criterion, and takes the error of the metering device into consideration; the electricity theft criterion is obtained through rigorous mathematical derivation, that is, when electricity theft occurs in the power system, the error between the resistance value obtained by reverse calculation through the metering device and the real resistance value becomes larger, greater than the error of the metering device, and lasts for a period of time, and when the electricity theft ends, the line resistance value is approximated to the real resistance value again, therefore, the present invention performs calculations based on the metering data and the flow data of the metering device respectively, and judges whether electricity theft occurs by comparing the results; the electricity theft identification method can be free from the restriction of the electricity theft type, and improves the universality of anti-electricity theft; at the same time, the electricity theft identification method of the present invention can not only accurately judge whether the electricity theft phenomenon occurs, but also determine the branch where the electricity theft occurs and the electricity theft time, which greatly improves the accuracy of anti-electricity theft and improves the efficiency of anti-electricity theft. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A flow chart of a method for identifying electricity theft based on electrical parameters of a power grid as described in the first specific implementation mode;

[0060] Figure 2 It is a branch error curve diagram when the power grid is operating normally without load changes in the first specific implementation mode;

[0061] Figure 3 It is a branch error curve diagram when the power grid is operating normally under load changes in the first specific implementation mode;

[0062] Figure 4 It is a diagram of the error of the power stealing branch line when power is stolen without load change in the first specific implementation mode;

[0063] Figure 5 It is a non-electricity-stealing branch line error diagram when electricity is stolen without load change in the first specific implementation mode;

[0064] Figure 6 It is a diagram of the error of the power stealing branch line when power is stolen under load variation in the first specific implementation mode. DETAILED DESCRIPTION

[0065] Specific implementation method 1. Combination Figures 1 to 6 To illustrate this embodiment, a method for identifying electricity theft based on electrical parameters of a power grid described in this embodiment includes the following steps:

[0066] Step 1: Use the measurement data of the branch metering equipment to obtain the calculated value of branch resistance R 计 ;

[0067] Step 2: Use the branch flow data to obtain the true value of the branch resistance R 真 ;

[0068] Step 3: Compare the calculated branch resistance value obtained in step 1 with the actual branch resistance value obtained in step 2 to generate a comparison result ΔR; the calculation formula of the comparison result ΔR is:

[0069] ΔR=R 计 -R 真

[0070] Step 4: The criteria for electricity theft are:

[0071]

[0072] It is determined whether electricity theft occurs in the branch circuit according to the electricity theft criterion.

[0073] In this implementation, firstly, the changing characteristics of the electrical parameters of the power grid before and after the power theft are analyzed from the perspective of the power network, and the line resistance is selected as the electrical parameter of the power theft identification method; then, an actual 10kV distribution network is built in the Matlab / Simulink environment, and the actual data is used for simulation, and the obtained waveform is analyzed to verify the feasibility of the method.

[0074] Selection of electricity theft criteria:

[0075] A circuit network model of the electricity theft load is established, that is, it is equivalent to an impedance model. When electricity theft occurs in the power system, it is equivalent to adding an unknown load to the power system. Using a circuit network to describe the electricity theft phenomenon is equivalent to adding an increment to the diagonal element corresponding to the electricity theft point in the node admittance matrix; after the electricity theft phenomenon occurs, since the amount of electricity theft is much less than the total amount of electricity in the entire network, it is generally believed that the output of the generator remains unchanged after the electricity theft phenomenon occurs. Based on this characteristic, the functional relationship between each electrical parameter in the power network and the electricity theft load is clarified, and the change law of the electrical parameters caused by electricity theft is summarized. The changes of the three parameters of voltage, current and power after the electricity theft phenomenon occurs are based on the normal operation to add a variable related to the electricity theft load, and the change law depends on the nature of the electricity theft load. However, for a certain power system, when its frequency remains unchanged, the line impedance of any branch in the network remains constant. In the steady state of the power system, the metering results of the metering equipment are consistent with the flow data. However, no matter what means are used to steal electricity, the ultimate goal is to reduce or eliminate the amount of electricity measured by the metering equipment, which leads to the metering results of the metering equipment being inconsistent with the power flow data or even a huge gap. The existence of electricity theft causes the metered power to be smaller than the actual power. The management of line loss includes the power loss caused by electricity theft, which is finally calculated together with the line loss, resulting in the theoretical line loss being much smaller than the actual line loss. According to the essence of the electricity theft problem, when electricity theft occurs, the metered related power is smaller, but the voltage of the first line is accurately measured. When the power system is operating normally, the line impedance calculated from the actual measured data is close to the true value. However, when electricity theft occurs, the line impedance calculated from the actual measured data will change, which will be different from the true line impedance. Since the electricity theft analysis is carried out in the non-fault state of the line, the line impedance that does not change with the change of the power grid operation is selected as the criterion. As we all know, line impedance includes line resistance and line reactance. Because the reactance will change due to the influence of frequency, and there are a certain amount of power electronic switches at the tail of the load of the power system, the opening and closing of the switch will cause the frequency to fluctuate, which will lead to changes in line reactance. Line resistance may be affected by temperature, but the temperature of the line will not change significantly during the period of power theft analysis, so it is assumed that the resistance remains almost unchanged. Based on the above analysis, it is feasible to select line resistance as the power theft criterion. In addition, the theoretical criterion for judging power theft is:

[0076]

[0077] Among them, R 计 is the calculated value of branch resistance; R 真is the true value of branch resistance. That is, when there is no electricity theft in the power system, the calculated branch resistance value obtained by reverse calculation based on the metering equipment data is equal to the true value of branch resistance. When there is electricity theft in the power system, the calculated branch resistance value obtained by reverse calculation based on the metering equipment data on the electricity theft line is subtracted from the true value of branch resistance, and the result is a negative value, while the value on the non-electricity theft line is still zero.

[0078] Simulation verification:

[0079] After the system model is built on the Matlab / Simulink software platform, first verify whether the electricity theft criterion mentioned above is met when there is no electricity theft, and then analyze the actual application of the electricity theft criterion when there is electricity theft, load fluctuation and no load fluctuation. Considering the rapidity of the simulation, the simulation time is set to 240 seconds, and the judgment is made according to the electricity theft criterion.

[0080] According to the above analysis of the power system, when the power network is operating normally and there is no electricity theft, the line resistance should be approximately equal to the actual resistance value, with an error of about 2%. That is, the obtained line resistance error curve fluctuates around 0-2%.

[0081] Simulation analysis during normal operation:

[0082] (1) No load change

[0083] Because electricity theft usually causes metering equipment to under-record or even ignore electricity consumption, but the voltage data measured by the metering equipment on the branch line is relatively accurate, and the relationship between the resistance value calculated based on the measured data and the actual resistance value.

[0084] When the power system is operating normally, the simulation time is set to 240s. Taking any branch in the network as an example, the branch error curve when there is no electricity theft is observed. The error curve when the power grid is operating normally is as follows: Figure 2 As shown. Figure 2 It can be seen that the error between the calculated value of the branch resistance and the actual value of the branch resistance is 2%, which is within the allowable error range and meets the electricity theft criterion.

[0085] (2) Load changes

[0086] For the power system in real life, there will be load changes, so we should take load fluctuations into account. Set the simulation time to 240s, and there will be load changes in the branch of the power system network. The load change is set to 120s. Observe the line resistance error curve of the branch. The line error curve of the power grid with load changes during normal operation is as follows: Figure 3 As shown. Figure 3It can be seen that the load change occurs in the power system at the 120th second. The load change involves operations such as switching, which will produce a transient process, but its duration is much shorter than the simulation time of 240 seconds. If electricity theft occurs, the theft time will also be longer than the transient duration, otherwise the electricity theft behavior has no practical significance.

[0087] Simulation analysis when electricity theft occurs:

[0088] (1) No load change

[0089] In the simulation of 240 seconds, the theft of electricity starts at the 60th second and ends at the 190th second. The active power of the theft is 11890 and the reactive power is 1334. The error between the calculated value of the branch resistance and the actual value of the branch resistance is calculated based on the metering data. The simulation results are as follows: Figure 4 In the non-power-stealing branch, check its line error waveform as shown below: Figure 5 As shown. Figure 4 It can be obtained that in the time period of 1 to 60 seconds, the line error is approximately 0%, which means that the line is operating normally and no electricity theft occurs; in the time period of 60 to 190 seconds, the line error exceeds 2% and lasts for a period of time, which means that electricity theft occurs on this line within 60 to 190 seconds. In the time period of 190 to 240 seconds, the line error returns to near 0, which means that the line is operating normally and the electricity theft has ended. The above judgment is the same as the simulation setting, which proves the correctness of the line resistance value that does not change with the operation of the power grid as the electricity theft criterion under static load conditions.

[0090] (2) Load fluctuation

[0091] For the power system operating in real life, there will be load changes, and the electricity theft behavior will continue for a period of time. During this period of time, there will inevitably be load changes, so the feasibility of the electricity theft judgment criteria when there are load changes should be analyzed.

[0092] In the simulation of 240 seconds, the load changes at 120 seconds, the power theft starts at 60 seconds, and ends at 190 seconds. The active power of the power theft is 11890, and the reactive power is 1334. The error between the calculated branch resistance and the true branch resistance is calculated based on the metering data. The simulation results are as follows: Figure 6 As shown. Figure 6 It can be seen that in the time period of 1 to 60 seconds, the line error is close to 0, judging that the power system is operating normally and no electricity theft occurs; in the time period of 60 to 120 seconds, the line error becomes larger, greater than 2% and lasts for a period of time, judging that electricity theft occurs in the power system; in the time period of 120 to 190 seconds, the error is still greater than 2% and lasts for a period of time, judging that electricity theft occurs in the power system; in the 120th second, there is a sudden change in the error, but the existence time is extremely short and Figure 3The load fluctuations shown are consistent, and it is judged that there is load fluctuation in the system at 120s. Since 120s exists between 60 and 190s, there is also electricity theft. The line error will be close to 0 from 190 to 240s, and it is judged that the power system is operating normally and the electricity theft disappears. The above judgment is the same as the simulation setting, which proves the correctness of the line resistance value that does not change with the operation of the power grid as the criterion for electricity theft in the case of load fluctuations.

[0093] comprehensive Figure 2 and Figure 4 The simulation results show that: for the case of no load change, when the power system is operating normally, the line resistance calculated by back-calculation of metering data is close to the actual resistance of the line, with an error within 2%; when there is electricity theft in the power system, there is a large gap between the calculated resistance value of the branch where the theft occurs and the actual value of the branch resistance, and it will last for a period of time. After the electricity theft ends, the error between the calculated resistance value of the branch and the actual value of the branch resistance will return to fluctuate around 0. Using the above characteristics, the line resistance can be used as the electrical reference quantity for electricity theft judgment to accurately determine the branch and time where the electricity theft occurs.

[0094] comprehensive Figure 2 and Figure 5 The simulation results show that: for load changes, it is similar to the power system without load, but the difference is that due to the load changes in the power system, there will be transient processes and transient data, and the sudden change of line errors or the contradiction with the requirements of the power theft judgment may cause misjudgment. However, the duration of the transient error mutation is very short, which is inconsistent with the power theft time, so it can be directly excluded without affecting the application of the power theft judgment.

[0095] In summary, according to the system simulation results, it can be concluded that selecting the line resistance value that is not affected by the operation of the power grid as the power grid electrical parameter for electricity theft judgment is feasible and accurate. At the same time, it can accurately find the branch where the electricity theft occurs and the time of the electricity theft, which is more convenient and reliable.

[0096] Specific implementation method 2: This implementation method further limits the method for identifying electricity theft based on electrical parameters of a power grid described in specific implementation method 1. In this implementation method, before using the metering data of the metering equipment on the branch line for calculation, the metering data of the metering equipment is corrected;

[0097] The specific method for correcting the metering data of the metering equipment is:

[0098] Step 1: Collect the electrical parameter data of the branch n times within the time T. The collected electrical parameter data are: X 1 , X 2 , ...Xn ;

[0099] Step 2: The variance D(X i ) as the criterion for whether the branch is in a steady state:

[0100] The specific judgment formula is:

[0101]

[0102] Where, σ is the electrical parameter data error; X i is the i-th electrical parameter data collected;

[0103] If the n electrical parameter data collected within the time T all meet the steady-state requirements of the branch, then execute step 3; otherwise, shorten the time T and return to execute step 1;

[0104] Step 3: Divide time T into m time periods and calculate the average value of the data in each time period k∈[1,m], where k is the kth time period;

[0105] when and The following relationship is satisfied;

[0106]

[0107] in, is the average value of n electrical parameter data;

[0108] Then, execute step 4; otherwise, shorten the time T and return to execute step 1;

[0109] Step 4: Collect the electrical parameter data X i Make corrections to obtain corrected electrical parameter data

[0110] The corrected electrical parameter data The calculation formula is:

[0111]

[0112] Among them, γ i is the correction coefficient of the i-th correction data;

[0113] Complete the correction of the measurement data of the measuring equipment.

[0114] In this embodiment, step 3 is to collect the electrical parameter data X iThe prerequisite for correction is that the purpose of step 3 is to determine whether the collected n electrical parameter data meet the steady-state requirements of the branch. Otherwise, the collected electrical parameter data X i Correction will not guarantee the accuracy of electricity theft judgment; using the corrected electrical parameter data X i Subsequent calculations are performed to improve the accuracy of electricity theft judgments. In distribution networks, load changes often occur, which is the process of the power system changing from one steady state to another, also called a transient process. The presence of transient data may affect the calculation results, and the real-time measurement system we currently use cannot completely clear the transient data, but we can use mathematical calculations to identify transient and steady-state data. By using the above mathematical methods to clear the transient data in the power system and retain the steady-state data, and using this data to judge electricity theft, the accuracy of the judgment can be improved to a certain extent.

[0115] Specific implementation method 3: This implementation method further limits the power theft identification method based on power grid electrical parameters described in specific implementation method 2. In this implementation method, in step 2, the variance D(X i ) is solved as follows:

[0116] First, find the average value of n electrical parameter data The average The calculation formula is:

[0117]

[0118] Finally, using the average value And the collected electrical parameter data X i Perform variance calculations;

[0119] The variance of n data D(X i ) is calculated as:

[0120]

[0121] In this embodiment, i∈[1,n], that is, X i The electrical parameter data collected is: X 1 , X 2 , ...X n Any one of them; the variance of n data is used as the criterion for whether the power system is in a steady state.

[0122] Specific implementation method 4: This implementation method further limits the method for identifying electricity theft based on electrical parameters of a power grid described in specific implementation method 2. In this implementation method, the value range of the electrical parameter data error σ is: 2%≤σ≤5%.

[0123] In this embodiment, in the current power system, it is considered that when the electrical parameter data error is between 2%≤σ≤5%, the power system is in a steady state.

[0124] Specific implementation method 5: This implementation method further limits the power theft identification method based on power grid electrical parameters described in specific implementation method 2. In this implementation method, the correction coefficient γ of the i-th correction data in step 6 is i The calculation formula is:

[0125]

[0126] In this embodiment, when and When the difference is within the allowable error range, the correction data is valid. i =1; otherwise, when the difference between the two is not within the allowable error range, the correction data is invalid, and the judgment γ i =0.

[0127] Specific implementation method 6: This implementation method further limits the power theft identification method based on power grid electrical parameters described in specific implementation method 1. In this implementation method, the specific method of obtaining the branch resistance calculation value in step 1 is:

[0128] Step 1. Obtain branch power according to the metering data of the metering equipment and the power consumption time; the specific calculation formula is:

[0129]

[0130] Where W is the metering data of the metering equipment; t is the electricity consumption time; P 支 is the branch power;

[0131] Step 12: According to the branch power obtained in step 11 and the rated voltage of the branch, obtain the calculated value of the branch resistance; the specific calculation formula is:

[0132]

[0133] Among them, R 计 is the calculated value of branch resistance; U 额 is the rated voltage of the branch.

[0134] In this embodiment, the metering data of the metering device, the power consumption time and the rated voltage of the branch are all known quantities; the calculated value of the branch resistance can be calculated according to the above formula, that is, the resistance value calculated by the metering device can be accurately calculated.

[0135] Specific implementation method 7: This implementation method further limits the power theft identification method based on power grid electrical parameters described in specific implementation method 1. In this implementation method, the specific method for obtaining the true value of the branch resistance in step 2 is:

[0136] According to the branch voltage and branch current in the power flow data, the true value of the branch resistance is obtained; the specific calculation formula is:

[0137]

[0138] Among them, R 真 is the true value of branch resistance; U 支 is the branch voltage in the power flow data; I 支 is the branch current in the power flow data.

[0139] In this embodiment, the branch voltage and branch current in the power flow data are known quantities, and the true value of the branch resistance can be directly calculated through the branch voltage and branch current, that is, the resistance value calculated by the metering equipment and the resistance value of the power theft access.

[0140] Specific implementation method 8: This implementation method further limits the method for identifying electricity theft based on electrical parameters of the power grid described in specific implementation method 1. In this implementation method, the calculation formula for generating the comparison result in step 3 is:

[0141]

[0142] In addition, the specific method for determining whether electricity theft occurs in the branch circuit in step 4 is as follows:

[0143] It is determined whether the comparison result is greater than the error threshold. If so, it indicates that electricity theft exists in the branch; otherwise, it indicates that electricity theft does not exist in the branch.

[0144] In this embodiment, when analyzing the electricity theft criterion theoretically, it is assumed that all nodes in the power system are equipped with metering devices and there are no errors, but the actual situation is different. The errors in the metering equipment are inevitable, so the errors must be taken into account in the electricity theft criterion. In the steady state of the power system, the metering results of the metering equipment are consistent with the flow data; however, no matter what means are used to steal electricity, the ultimate goal is to reduce the amount of electricity measured by the metering equipment or not to measure the amount of electricity used, which leads to the metering results of the metering equipment being inconsistent with the flow data, and even a huge gap. The existence of electricity theft causes the metered power to be smaller than the actual power. The management line loss includes the power loss caused by electricity theft, and finally it is calculated uniformly with the line loss, which leads to the theoretical line loss being much smaller than the actual line loss.

[0145] Specific implementation method 9: This implementation method further limits the method for identifying electricity theft based on electrical parameters of a power grid described in specific implementation method 9. In this implementation method, the error threshold is 2%.

[0146] In this embodiment, the accuracy of the line resistance calculated from the measured data during normal operation is 2.0; when there is no electricity theft in the power system, the line resistance calculated from the measured data has an error of 2% with the real data, that is, it fluctuates around the real data. Once electricity theft occurs in the power system, the line resistance calculated from the reverse calculation will change greatly and last for a period of time. When the electricity theft disappears, the data will return to the vicinity of the real data, so that the location and time of the electricity theft can be determined.

[0147] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for identifying electricity theft based on electrical parameters of a power grid, characterized in that: The following steps are involved: Step 1: Use the measurement data of the branch metering equipment to obtain the calculated value of branch resistance R 计 ; Step 2: Use the branch flow data to obtain the true value of the branch resistance R 真 ; Step 3: Compare the calculated branch resistance value obtained in step 1 with the actual branch resistance value obtained in step 2 to generate a comparison result ΔR; the calculation formula of the comparison result ΔR is: ΔR=R 计 -R 真 Step 4: The criteria for electricity theft are: It is determined whether electricity theft occurs in the branch circuit according to the electricity theft criterion.

2. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 1, characterized in that: Before using the metering data of the metering equipment on the branch line for calculation, the metering data of the metering equipment is corrected; The specific method for correcting the metering data of the metering equipment is: Step 1: Collect the electrical parameter data of the branch n times within the time T. The collected electrical parameter data are: X1, X2, ... X n ; Step 2: The variance D(X i ) as the criterion for whether the branch is in a steady state: The specific judgment formula is: Where, σ is the electrical parameter data error; X i is the i-th electrical parameter data collected; If the n electrical parameter data collected within the time T all meet the steady-state requirements of the branch, then execute step 3; otherwise, shorten the time T and return to execute step 1; Step 3: Divide time T into m time periods and calculate the average value of the data in each time period k∈[1,m], where k is the kth time period; when and The following relationship is satisfied; in, is the average value of n electrical parameter data; Then, execute step 4; otherwise, shorten the time T and return to execute step 1; Step 4: Collect the electrical parameter data X i Make corrections to obtain corrected electrical parameter data The corrected electrical parameter data The calculation formula is: Among them, γ i is the correction coefficient of the i-th correction data; Complete the correction of the measurement data of the measuring equipment.

3. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 2 is characterized in that: Step 2: Variance D(X i ) is solved as follows: First, find the average value of n electrical parameter data The average The calculation formula is: Finally, using the average value And the collected electrical parameter data X i Perform variance calculations; The variance of n data D(X i ) is calculated as:

4. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 2 is characterized in that: The value range of the electrical parameter data error σ in step 2 is: 2%≤σ≤5%.

5. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 2, characterized in that: The correction coefficient γ of the i-th correction data in step 4 i The calculation formula is:

6. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 1, characterized in that: The specific method for obtaining the calculated value of branch resistance in step 1 is: Step 1. Obtain branch power according to the metering data of the metering equipment and the power consumption time; the specific calculation formula is: Where W is the metering data of the metering equipment; t is the electricity consumption time; P 支 is the branch power; Step 12: According to the branch power obtained in step 11 and the rated voltage of the branch, obtain the calculated value of the branch resistance; the specific calculation formula is: Among them, R 计 is the calculated value of branch resistance; U 额 is the rated voltage of the branch.

7. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 1, characterized in that: The specific method for obtaining the true value of the branch resistance in step 2 is: According to the branch voltage and branch current in the power flow data, the true value of the branch resistance is obtained; the specific calculation formula is: Among them, R 真 is the true value of branch resistance; U 支 is the branch voltage in the power flow data; I 支 is the branch current in the power flow data.

8. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 1, characterized in that: The calculation formula for generating the comparison result in step 3 is replaced by: In addition, the specific method for determining whether electricity theft occurs in the branch circuit in step 4 is: It is determined whether the comparison result is greater than the error threshold. If so, it indicates that electricity theft exists in the branch; otherwise, it indicates that electricity theft does not exist in the branch.

9. The method for identifying electricity theft based on electrical parameters of a power grid according to claim 8, characterized in that: The error threshold is 2%.

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