Online Monitoring and Location Method for Electricity Theft Problem Based on Beidou

Abstract

This application relates to an online monitoring and positioning method for electricity theft problems based on Beidou, including the following specific steps: triggering a sampling signal by the Beidou synchronous clock, and simultaneously performing ADC sampling at measuring points of different circuits; accumulating the instantaneous values collected at the same moment on the branch line to form the instantaneous value of the current of the virtual measuring point on the virtual upper-level line; calculating the effective current value respectively according to the measured instantaneous current value and the instantaneous current value of the virtual measuring point; comparing the effective current values of the measured point and the virtual measuring point, calculating the difference of the effective current values, and determining whether there is current abnormality according to the difference; when there is current abnormality, performing subtraction calculation on the instantaneous values of the measured point and the virtual measuring point to analyze whether it is leakage or electricity theft; when there is current abnormality, providing more judgment basis for the qualitative determination of the leakage current. This application can identify whether it is leakage current or electricity theft by performing harmonic analysis on the leakage current and combining the characteristics of electrical equipment.

Description

Technical Field

[0001] The present application relates to the field of power distribution network electricity theft monitoring, and in particular to an online monitoring and positioning method for electricity theft problems based on Beidou. Background Art

[0002] In the application of power distribution networks, there are usually phenomena such as current leakage or electricity theft. For current leakage, leakage protection devices are usually used to solve the problem. Leakage protection devices have good protection effects in homes and other indoor places, but they have many disadvantages for power distribution lines. Due to weather reasons, current leakage is inevitable. Such leakage has little harm to the power grid and users, but if the leakage protection device takes protective actions on it, it will cause frequent power outages, having a greater impact on production and life.

[0003] Regarding the phenomenon of electricity theft, there are currently manual on-site inspections, electricity quantity statistics methods, and current statistics methods, and each method has great limitations.

[0004] Manual on-site inspections have the disadvantages of large workload, missed measurement points, hidden electricity theft lines, or the inability to detect electricity theft due to the restoration of the electricity theft lines to their original state.

[0005] The electricity quantity statistics method can only be statistically monthly, with a large lag, and there is also the problem of being unable to locate the specific line or location of electricity theft.

[0006] For the current comparison method, it is measured manually or by a metering device, comparing the current at the upper and lower ends of the line to be measured, and judging according to the difference. Due to the statistical time difference, especially under load fluctuations, there will be deviations between measurement points, affecting the judgment. Due to the influence of the power factor, the current method can only measure a single line and cannot measure a branched line. Summary of the Invention

[0007] The purpose of the embodiments of the present application is to provide an online monitoring and positioning method for electricity theft problems based on Beidou, which can monitor in real time and quickly (within 2 seconds) provide current leakage (or electricity theft) alarms, and provide line information to analyze the power and harmonics of the current, so as to determine whether it is current leakage or electricity theft.

[0008] To achieve the above purpose, the present application provides the following technical solutions:

[0009] The embodiments of the present application provide an online monitoring and positioning method for electricity theft problems based on Beidou, including the following specific steps:

[0010] Trigger a sampling signal by a Beidou synchronous clock, and simultaneously perform ADC sampling on the measurement points of different circuits, and perform AC sampling on the voltage of the upper-level line, the current at the measured point, and the current of the lower-level branch line at the same sampling frequency;

[0011] Accumulate the instantaneous values collected from the branch circuits at the same moment to form the instantaneous value of the current at the virtual measuring point of the virtual upper-level circuit;

[0012] Calculate the effective current values respectively according to the measured instantaneous current value and the instantaneous current value at the virtual measuring point;

[0013] Compare the effective current values at the measured point and the virtual measuring point, calculate the difference in the effective current values, and determine whether there is current abnormality according to the difference;

[0014] When there is current abnormality, perform subtraction calculation on the instantaneous values at the measured point and the virtual measuring point to obtain the instantaneous value of the differential current, and perform FFT calculation on it to obtain the total distortion rate and the harmonic content rate of each order. Combine the harmonic characteristics of the common load current to analyze whether it is leakage or power theft;

[0015] When there is current abnormality, calculate using the measured instantaneous voltage value and the instantaneous value of the differential current to obtain the active power, reactive power and power factor of the leakage current. Combine the power characteristics analysis of leakage and power theft to provide more judgment basis for the qualitative determination of the leakage current.

[0016] The sampling signal is triggered by the Beidou synchronous clock, and the measuring points of different circuits perform ADC sampling simultaneously. AC sampling is performed on the upper-level circuit voltage, the measured point current and the lower-level branch circuit current at the same sampling frequency. Specifically, the pps signal based on Beidou is used as the AD trigger synchronization signal, and the synchronized sampled current is connected to the server through the 4G network. The server interacts and synthesizes a new current vector to realize current comparison.

[0017] The specific calculation of the effective current value is as follows: the effective current value:

[0018] where \(i(t)\) is the instantaneous value of the current, \(t\) represents time, and \(T\) is the total sampling time.

[0019] The difference in the effective current value: \(\Delta I = I\) cd6 -I c ′ d6 , where \(I\) cd6 represents the effective current value at the measured point, and \(I\) c ′ d6 represents the effective current value at the virtual measuring point.

[0020] The instantaneous value of the differential current: \(\Delta i(t)=i\) cd6 (t)-i c ′ d6 (t)

[0021] The FFT calculation formula: where k = (0, 1, 2, …, N - 1), X(k) represents the complex value at the k-th frequency in the frequency domain, and x(n) is the sampled discrete-time series, i.e., the instantaneous value of the differential current.

[0022] Total distortion rate:

[0023] Harmonic content rate of the h-th order: where U h represents the voltage of the h-th harmonic (root mean square value), and U1 represents the fundamental voltage.

[0024] Compared with the prior art, the beneficial effects of this application are as follows: By using the Beidou synchronization signal, synchronous sampling can be performed on power lines with branches. The instantaneous values of the branch line currents are recalculated, a new current vector is synthesized, and it is compared with the upper-level main line. If the difference exceeds the predetermined amplitude, it can be determined that there is a leakage or power theft phenomenon in the line.

[0025] By calculating the leakage current component, the active current (resistive current), reactive current (capacitive and inductive current), fundamental current, and harmonic current are decomposed. The power factor, amplitude, distortion rate, and other characteristics of the leakage current are comprehensively evaluated to determine whether it is a leakage current or power theft.

[0026] By performing harmonic analysis on the leakage current and combining the characteristics of electrical equipment, it is identified whether it is a leakage current or power theft. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required to be used in the embodiments of this application. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 is a schematic diagram of the line principle provided by an embodiment of the present invention;

[0029] Figure 2 is a flowchart of the Beidou synchronous clock trigger sampling signal provided by an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of the instantaneous value accumulation of the branch line provided by an embodiment of the present invention;

[0031] Figure 4 is a sampling data diagram of abnormal current conditions provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the accompanying drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0033] The term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the presence of additional identical elements in the process, method, article or device including the said element.

[0034] Terms such as "first", "second", etc. are only used to distinguish one entity or operation from another entity or operation, and cannot be understood as indicating or implying relative importance, nor can it be understood as requiring or implying any actual relationship or order between these entities or operations.

[0035] Please refer to Figures 1 - 4 , the embodiments of the present application provide an online monitoring and positioning method for electricity theft problems based on Beidou. For suspected lines (leakage or electricity theft), measurements can be made at key nodes. Since the load types on the power consumption lines are different, their power factors are almost all different. Even for the same type of load, at different load rates, their power factors also have large differences. Therefore, the effective value of the current at the upper measurement point is not necessarily equal to the sum of the effective values of the currents of the lower branch lines. As shown in the figure above: Total measurement point ≠ Measurement point 1 + Measurement point 3, Measurement point 6 ≠ Measurement point 7 + Measurement point 8.

[0036] The methods for measuring electricity leakage and theft in this article are as follows:

[0037] Perform AC sampling (256 sampling points / 20 ms) on the voltage and current of the upper-level line (measurement point 6) and the currents of the lower-level branch lines (measurement points 7 and 8) at the same sampling frequency, and the start sampling signal comes from the same trigger signal.

[0038] Accumulate the instantaneous values collected at the same moment for the branch lines (measurement points 7 and 8) to form the instantaneous value of the current of the virtual upper-level line (virtual measurement point 6) (256 sampling points).

[0039] Calculate the effective values of the current based on the measured instantaneous value of the current at measurement point 6 and the virtual measurement point (virtual measurement point 6) respectively.

[0040] Effective value of current:

[0041] Among them, i(t) is the instantaneous value of the current, t represents time, and T is the total sampling time.

[0042] Compare the effective current values of measuring point 6 and virtual measuring point 6, calculate the difference in effective current values, and determine whether there is current abnormality based on the difference.

[0043] Difference in effective current value: ΔI = I cd6 -I c ′ d6 , where I cd6 represents the effective current value of measuring point 6, and I c ′ d6 represents the effective current value of virtual measuring point 6.

[0044] When there is current abnormality, perform subtraction calculation on the instantaneous values of measuring point 6 and virtual measuring point 6 to obtain the instantaneous value of the differential current, and perform FFT calculation on it to obtain the total distortion rate and the harmonic content rate of each order. Combine the harmonic characteristics of common load currents to analyze whether it is leakage or power theft.

[0045] Instantaneous value of differential current: Δi(t) = i cd6 (t) - i c ′ d6 (t)

[0046] FFT calculation formula: where k = (0, 1, 2,..., N - 1), X(k) represents the complex value of the kth frequency in the frequency domain, and x(n) is the discrete time series of sampling, that is, the instantaneous value of the differential current.

[0047] Total distortion rate:

[0048] Harmonic content rate of the hth order: where U h represents the voltage of the hth harmonic (root mean square value), and U1 represents the fundamental voltage (root mean square value)

[0049] When there is current abnormality, calculate using the instantaneous voltage value of measuring point 6 and the instantaneous value of the differential current to obtain the active power, reactive power, and power factor of the leakage current. Combine the power characteristics (capacitive, resistive, inductive) of leakage and power theft for analysis, and further provide more judgment bases for the qualitative determination of the leakage current.

[0050] Active power: where u(t) represents the instantaneous voltage value, and Δi(t) represents the instantaneous value of the differential current.

[0051] Reactive power:

[0052] Power factor:

[0053] In this solution, the sampling synchronization signal comes from the Beidou satellite positioning module. By using the PPS signal and NEMA data, the achieved precision can reach the nanosecond level. The sampling signal is triggered by the Beidou synchronous clock, and the measuring points of different loops simultaneously perform ADC sampling. The sampling time point error of each measuring point can be controlled within the nanosecond level. The flow chart is as Figure 2 shown:

[0054] For the measuring points of the same loop (i.e., measuring point 1 and measuring point 2), if the effective current values obtained by sampling different measuring points are the same (or the deviation is within 0.5%), there is no electricity leakage or power theft. Otherwise, there is an abnormal current situation.

[0055] For the measuring points of different loops, for example: measuring point 6, measuring point 7, and measuring point 8. Since the effective current value of measuring point 6 ≠ the sum of the effective current values of measuring point 7 and measuring point 8. Therefore, the instantaneous values at the same moment of each branch (measuring point 7 and measuring point 8) are added to obtain a new sampling data (i.e., the sampling data of the virtual measuring point 6), as follows Figure 3 shown:

[0056] Then, calculate the sampling data of measuring point 6 and the virtual measuring point 6 to obtain the corresponding effective current values, and thus calculate the difference in effective current values to determine whether there is an abnormal current situation. When there is an abnormal current situation, the sampling data is as Figure 4 shown:

[0057] Handling of abnormal current situation:

[0058] When there is an abnormal current situation, perform FFT calculation, active power calculation, reactive power calculation, and power factor calculation through the instantaneous voltage value u(t) of measuring point 6 and the differential current instantaneous value Δi(t), and combine the characteristics in different situations of electricity leakage and power theft to determine whether the type of abnormal situation is power theft or electricity leakage.

[0059] Location of abnormal loop: Determine the range of the abnormal loop through the Beidou satellite positioning modules installed at different measuring points, thereby narrowing the scope of later investigation. Upload data to the server in real time, which can ensure the timeliness of monitoring, and ensure the accuracy of the measuring point location through Beidou positioning.

[0060] The above description is only for the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An online monitoring and positioning method for electricity theft problems based on Beidou, characterized in that, It includes the following specific steps: Trigger the sampling signal by the Beidou synchronous clock. The measuring points of different circuits perform ADC sampling simultaneously, and AC sampling is carried out on the voltage of the upper-level line, the current of the measured point, and the current of the lower-level branch line at the same sampling frequency. Accumulate the instantaneous values collected from the branch lines at the same moment to form the instantaneous value of the virtual measuring point current of the virtual upper-level line. Calculate the effective current values respectively according to the instantaneous value of the measured point current and the instantaneous value of the virtual measuring point current. Compare the effective current values of the measured point and the virtual measuring point, calculate the difference of the effective current values, and determine whether there is current abnormality according to the difference. When there is current abnormality, perform subtraction calculation on the instantaneous values of the measured point and the virtual measuring point to obtain the instantaneous value of the differential current, and perform FFT calculation on it to obtain the total distortion rate and the harmonic content rate of each order. Combine the harmonic characteristics of the common load current to analyze whether it is leakage or theft of electricity. When there is current abnormality, calculate using the instantaneous value of the measured point voltage and the instantaneous value of the differential current to obtain the active power, reactive power, and power factor of the leakage current. Combine the power characteristics analysis of leakage and theft of electricity to provide more judgment basis for the qualitative determination of the leakage current. Trigger the sampling signal by the Beidou synchronous clock. The measuring points of different circuits perform ADC sampling simultaneously, and AC sampling is carried out on the voltage of the upper-level line, the current of the measured point, and the current of the lower-level branch line at the same sampling frequency. Specifically, based on the pps signal of Beidou as the AD trigger synchronization signal, the synchronized sampled current is connected to the server through the 4G network, and the server interacts and synthesizes a new current vector to achieve current comparison. For the measuring points of the same circuit, if the effective current values obtained by sampling different measuring points are the same or the deviation is within 0.5%, there is no leakage or theft of electricity. Otherwise, there is current abnormality. For the measuring points of different circuits, add the instantaneous values of the same moment of each branch to obtain a new sampling data, and then calculate the sampling data of the measured point and the virtual measuring point to obtain the corresponding effective current values, so as to calculate the difference of the effective current values to judge whether there is current abnormality.

2. The on-line monitoring and positioning method for electricity stealing problems based on Beidou according to claim 1, characterized in that, The specific calculation of the effective current value is as follows: the effective current value: , where is the instantaneous value of the current, represents time, is the total sampling time.

3. The online monitoring and positioning method for electricity theft problems based on Beidou according to claim 1, characterized in that, The difference in the effective value of the current: , where represents the effective value of the current at the measured point, represents the effective value of the current at the virtual measurement point.

4. An online monitoring and positioning method for electricity theft problems based on Beidou according to claim 1, characterized in that, Instantaneous value of differential current: , FFT calculation formula: , where , represents the complex value of the k-th frequency in the frequency domain, is the sampled discrete time series, that is, the instantaneous value of the differential current; Total distortion rate: , Harmonic content rate of the h-th harmonic: , where represents the voltage of the h-th harmonic, represents the fundamental voltage.

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