Abnormal early warning method and system for reactive power compensation device

Abstract

The invention discloses a reactive power compensation device abnormity early warning method and system, and the method comprises the steps: regularly updating an early warning threshold library, judging whether the reactive power compensation device has an overvoltage risk or not based on the early warning threshold library according to an equivalent voltage factor and voltage skewness, if yes, outputting overvoltage early warning information, and if not, outputting the overvoltage early warning information; and judging whether the reactive power compensation device has an overcurrent risk according to the harmonic current quadratic sum based on an early warning threshold library, if so, outputting overcurrent early warning information, judging whether the reactive power compensation device has a capacitance deviation abnormal risk based on the early warning threshold library according to the capacitance deviation data, and if so, outputting capacitance deviation abnormal early warning information. Therefore, the overvoltage, overcurrent and capacitance deviation abnormity of the reactive power compensation device can be early warned more effectively and reliably, meanwhile, the early warning threshold value library is updated regularly, it is ensured that the threshold values in the early warning threshold value library can be updated in real time according to recent historical data, accurate early warning of abnormal risks is ensured, and the safety of the reactive power compensation device is improved. Therefore, more accurate and reliable abnormity early warning of the reactive power compensation device is realized.

Description

Technical Field

[0001] The present invention relates to the field of reactive power compensation devices, and in particular to an abnormality early warning method and system for reactive power compensation devices. Background Art

[0002] Reactive power compensation and reactive power balance in the power system are the basic conditions for ensuring voltage quality. Insufficient or excessive reactive power will cause the system voltage to drop or rise. In extreme cases, it may cause the bus voltage of some hub transformers to drop sharply and cause "voltage collapse". The large-scale access of new energy power generation such as photovoltaic and wind power has brought a series of technical challenges to the power grid. For example, power quality problems such as voltage fluctuation and increased harmonics are more prominent, which puts higher requirements on the performance of reactive power compensation devices. On the one hand, reactive power compensation devices need to have higher stability and reliability to cope with various complex situations in the power system; on the other hand, reactive power compensation devices also need to have higher adjustment capabilities and flexibility to adapt to the volatility and uncertainty of renewable energy power generation. Therefore, it is of great significance to use digital technology to collect key operating data of reactive power compensation devices in real time, deeply explore the trend characteristics of the operating status of reactive power compensation devices, and conduct abnormal warnings.

[0003] Typical fault types of reactive power compensation devices include bulging, blown fuses, component breakdown, switching failure, oil leakage, etc. Among them, overvoltage, overcurrent and other adverse operating conditions are the dominant external factors causing device failures. Major faults such as bulging, blown fuses and component breakdown are all reflected in changes in capacitance. Therefore, it is necessary to carry out early warning for overvoltage, overcurrent and capacitance deviation. Measured data show that adverse operating conditions such as overvoltage, overcurrent and abnormal capacitance deviation all have early abnormal signs. The online monitoring data obtained by the reactive power compensation equipment status monitoring device uses data feature correlation analysis technology to judge the abnormal operation status, which can track and warn early faults, avoid the development and expansion of faults, and improve the operational reliability of reactive power compensation devices.

[0004] The main problem in early warning of overvoltage, overcurrent and capacitance deviation of reactive power compensation devices is that it is difficult to determine the early warning threshold and related criteria, which is specifically reflected in the following aspects:

[0005] 1) The current national standard defines the permissible operating level of long-term overvoltage amplitude, but it is difficult to reasonably determine the overvoltage warning threshold and criteria;

[0006] 2) Overcurrent is caused by the combined effect of harmonics and overvoltage of 1.1 times or less of the rated voltage. Considering the influence of harmonics, the warning threshold cannot be determined;

[0007] 3) The capacitance deviation warning threshold cannot be scientifically determined. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method and system for abnormal warning of a reactive power compensation device, so as to achieve more accurate and reliable abnormal warning of the reactive power compensation device.

[0009] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0010] A reactive power compensation device abnormality early warning method, comprising the steps of:

[0011] Regularly update the warning threshold library;

[0012] Obtain the equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device;

[0013] Based on the warning threshold library, judging whether the reactive power compensation device has an overvoltage risk according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information;

[0014] Based on the warning threshold library, judging whether the reactive power compensation device has an overcurrent risk according to the square sum of the harmonic currents, and if so, outputting overcurrent warning information;

[0015] Based on the warning threshold library, it is determined according to the capacitance deviation data whether the reactive power compensation device has a capacitance deviation abnormality risk. If so, capacitance deviation abnormality warning information is output.

[0016] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0017] A reactive power compensation device abnormality warning system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented:

[0018] Regularly update the warning threshold library;

[0019] Obtain the equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device;

[0020] Based on the warning threshold library, judging whether the reactive power compensation device has an overvoltage risk according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information;

[0021] Based on the warning threshold library, judging whether the reactive power compensation device has an overcurrent risk according to the square sum of the harmonic currents, and if so, outputting overcurrent warning information;

[0022] Based on the warning threshold library, it is determined according to the capacitance deviation data whether the reactive power compensation device has a capacitance deviation abnormality risk. If so, capacitance deviation abnormality warning information is output.

[0023] The beneficial effects of the present invention are: regularly updating the early warning threshold library, judging whether the reactive compensation device has an overvoltage risk based on the equivalent voltage factor and voltage deviation based on the early warning threshold library, and if so, outputting overvoltage early warning information, judging whether the reactive compensation device has an overcurrent risk based on the harmonic current sum of squares based on the early warning threshold library, and if so, outputting overcurrent early warning information, judging whether the reactive compensation device has a capacitor deviation abnormality risk based on the early warning threshold library according to the capacitor deviation data, and if so, outputting capacitor deviation abnormality early warning information, thereby giving an early warning of overvoltage risk through the equivalent voltage factor and voltage deviation, giving an early warning of overcurrent risk through the harmonic current sum of squares, and giving an early warning of capacitor deviation abnormality risk through the capacitor deviation data, and being able to more effectively and reliably give early warning of overvoltage, overcurrent and capacitor deviation abnormalities of the reactive compensation device, and at the same time regularly updating the early warning threshold library to ensure that the thresholds in the early warning threshold library can be updated in real time according to recent historical data, thereby ensuring accurate early warning of abnormal risks, and thus achieving more accurate and reliable abnormal early warning of reactive compensation devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flowchart of a method for abnormal warning of a reactive power compensation device according to an embodiment of the present invention;

[0025] Figure 2 A schematic structural diagram of an abnormal warning system for a reactive power compensation device according to an embodiment of the present invention;

[0026] Figure 3 It is a warning schematic diagram of an abnormal warning method for a reactive power compensation device according to an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of generating a capacitance deviation abnormal threshold in a reactive power compensation device abnormality warning method according to an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of abnormality analysis and judgment in the abnormality early warning method of reactive power compensation device according to an embodiment of the present invention;

[0029] Figure 6 It is a schematic diagram of a control diagram in the abnormal warning method for a reactive power compensation device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0031] Please refer to Figure 1, a reactive power compensation device abnormality early warning method, comprising the steps of:

[0032] Regularly update the warning threshold library;

[0033] Obtain the equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device;

[0034] Based on the warning threshold library, judging whether the reactive power compensation device has an overvoltage risk according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information;

[0035] Based on the warning threshold library, judging whether the reactive power compensation device has an overcurrent risk according to the square sum of the harmonic currents, and if so, outputting overcurrent warning information;

[0036] Based on the warning threshold library, it is determined according to the capacitance deviation data whether the reactive power compensation device has a capacitance deviation abnormality risk. If so, capacitance deviation abnormality warning information is output.

[0037] From the above description, it can be seen that the beneficial effects of the present invention are: regularly updating the warning threshold library, judging whether the reactive compensation device has an overvoltage risk based on the warning threshold library according to the equivalent voltage factor and voltage deviation, and if so, outputting overvoltage warning information, judging whether the reactive compensation device has an overcurrent risk based on the warning threshold library according to the harmonic current square sum, and if so, outputting overcurrent warning information, judging whether the reactive compensation device has a capacitor deviation abnormality risk based on the warning threshold library according to the capacitor deviation data, and if so, outputting capacitor deviation abnormality warning information, thereby warning of overvoltage risks through equivalent voltage factors and voltage deviations, warning of overcurrent risks through the harmonic current square sum, and warning of capacitor deviation abnormal risks through capacitor deviation data, which can more effectively and reliably warn of overvoltage, overcurrent and capacitor deviation abnormalities of the reactive compensation device, and at the same time regularly updating the warning threshold library to ensure that the thresholds in the warning threshold library can be updated in real time according to recent historical data, ensuring accurate warning of abnormal risks, thereby achieving more accurate and reliable abnormal warning of reactive compensation devices.

[0038] Furthermore, the periodic updating of the warning threshold library includes:

[0039] Acquire the equivalent voltage factor and voltage deviation of the reactive power compensation device in a historical preset time period, and identify the voltage step time and step number based on the equivalent voltage factor;

[0040] Selecting, from the voltage deviations of the reactive power compensation device in the historical preset time period, the voltage deviation within a first preset time length before the voltage step moment and the voltage deviation within a first preset time length after the voltage step moment;

[0041] Calculating an average value of the voltage deviation within a first preset time length before the voltage step moment as a first overvoltage abnormal threshold value corresponding to the step number, and calculating an average value of the voltage deviation within a first preset time length after the voltage step moment as a second overvoltage abnormal threshold value corresponding to the step number;

[0042] Updating the first overvoltage abnormality threshold and the second overvoltage abnormality threshold to a warning threshold library;

[0043] Selecting a target equivalent voltage factor that is less than or equal to a first preset value from the equivalent voltage factors of the reactive power compensation device in the historical preset time period, and acquiring a fundamental current amplitude corresponding to the target equivalent voltage factor;

[0044] Calculate an overcurrent abnormality threshold based on the fundamental current amplitude, and update the overcurrent abnormality threshold to the warning threshold library;

[0045] Acquiring capacitance deviation data of the reactive power compensation device in the historical preset time period;

[0046] Calculating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart using the control chart method based on the capacitance deviation data, and updating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart as capacitance deviation abnormality thresholds to the early warning threshold library;

[0047] The step of obtaining the equivalent voltage factor and voltage deviation of the reactive power compensation device in the historical preset time period is performed again at intervals of the preset time period.

[0048] From the above description, it can be seen that the equivalent voltage factor and voltage deviation of the reactive compensation device in the historical preset time period are obtained, and the overvoltage abnormal threshold is calculated based on them and updated to the early warning threshold library. The overcurrent abnormal threshold is calculated according to the fundamental current amplitude corresponding to the target equivalent voltage factor, and it is updated to the early warning threshold library. According to the capacitance deviation data of the reactive compensation device in the historical preset time period, the upper control line and lower control line of the standard deviation control chart and the upper control line and lower control line of the mean control chart are calculated using the control chart method as the capacitance deviation abnormal threshold and updated to the early warning threshold library, thereby determining more scientific and reasonable early warning thresholds for overvoltage, overcurrent and capacitance deviation abnormalities.

[0049] Further, the calculating of the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart using the control chart method based on the capacitance deviation data includes:

[0050] Grouping the capacitance deviation data to obtain multiple sample groups;

[0051] Calculating the mean and standard deviation of each sample group in the multiple sample groups, and calculating the mean and standard deviation of the multiple sample groups based on the mean and standard deviation of each sample group;

[0052] Calculate the upper control line, center line and lower control line of the standard deviation control chart based on the standard deviations of the multiple sample groups;

[0053] Generate a standard deviation control chart based on the upper control line, the center line and the lower control line of the standard deviation control chart, and use the capacitance deviation data to mark points in the standard deviation control chart;

[0054] Determine whether the sample points in the standard deviation control chart are stable. If not, remove the unstable sample points, add the same number of new sample points as the unstable sample points into the capacitance deviation data, and regenerate the standard deviation control chart until the sample points in the standard deviation control chart are stable.

[0055] Calculate the upper control line, center line and lower control line of the mean control chart based on the means and standard deviations of the plurality of sample groups;

[0056] Generate a mean control chart based on the upper control line, the center line and the lower control line of the mean control chart, and use the capacitance deviation data to mark points in the mean control chart;

[0057] Determine whether the sample points in the mean control graph are stable. If not, remove the unstable sample points, add the same number of new sample points as the unstable sample points into the capacitance deviation data, and regenerate the mean control graph until the sample points in the mean control graph are stable.

[0058] From the above description, it can be seen that based on the capacitance deviation data, the control chart method is used to calculate the upper control line and lower control line of the standard deviation control chart and the upper control line and lower control line of the mean control chart. The upper control line and lower control line of the standard deviation control chart and the upper control line and lower control line of the mean control chart can be used to intuitively and accurately identify the abnormality of capacitance deviation.

[0059] Further, the determining whether the sample points in the standard deviation control chart are stable includes:

[0060] Determine whether there are a first preset number of consecutive sample points in the standard deviation control chart within the range formed by the upper control line and the lower control line of the standard deviation control chart. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a second preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a second preset value. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a third preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a third preset value. If so, determine that the sample points in the standard deviation control chart are stable. If so, determine that the sample points in the standard deviation control chart are unstable.

[0061] From the above description, it can be seen that by judging the stability of the sample points to confirm whether the currently generated standard deviation control chart is valid, the rationality of the upper control line and the lower control line of the standard deviation control chart stored in the warning threshold library is ensured.

[0062] Furthermore, the acquisition of equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device includes:

[0063] Collect the phase voltage of the access bus of the reactive power compensation device, the line voltage of the access bus and the instantaneous value of the outgoing line current;

[0064] Calculate the fundamental phase voltage amplitude and phase, the fundamental line voltage amplitude and phase, the fundamental current amplitude and phase, and the harmonic current amplitude and phase based on fast Fourier transform according to the phase voltage of the access bus, the line voltage of the access bus, and the instantaneous value of the outgoing line current;

[0065] Calculating an equivalent voltage factor according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase;

[0066] Calculating a voltage deviation based on the equivalent voltage factor;

[0067] Calculating a sum of squares of harmonic currents based on the harmonic current amplitudes and phases;

[0068] Capacitance deviation is calculated based on Kirchhoff's law based on the fundamental current amplitude and phase and the harmonic current amplitude and phase.

[0069] From the above description, it can be seen that the equivalent voltage factor is calculated according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase, the voltage deviation is calculated based on the equivalent voltage factor, the sum of squares of harmonic currents is calculated based on the harmonic current amplitude and phase, the capacitance deviation is calculated based on Kirchhoff's law based on the fundamental current amplitude and phase and the harmonic current amplitude and phase, and the equivalent voltage factor, voltage deviation, sum of squares of harmonic currents and capacitance deviation data are used as data basis for subsequent early warning, thereby realizing accurate identification of abnormal status of reactive compensation device.

[0070] The equivalent voltage factor is calculated according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase as follows:

[0071]

[0072] Where U e Indicates the equivalent voltage factor, U a1 Indicates the effective value of the fundamental phase voltage of phase A, U b1 Indicates the effective value of the fundamental phase voltage of phase B, U c1 Indicates the effective value of the fundamental phase voltage of phase C, U ab1 Indicates the effective value of the fundamental line voltage between phase A and phase B, U bc1 Indicates the effective value of the fundamental line voltage between phase B and phase C, U ca1 It represents the effective value of the fundamental line voltage between phase C and phase A, and U0 represents the rated voltage of the reactive compensation device;

[0073] The voltage deviation is calculated based on the equivalent voltage factor as follows:

[0074]

[0075] In the formula, δ represents the voltage skewness, E(·) represents the expected function, and μ represents the average value of the equivalent voltage;

[0076] Calculating the sum of squares of harmonic currents based on the harmonic current amplitudes and phases comprises:

[0077]

[0078] Where, I represents the square sum of harmonic currents, I Ch Indicates the hth harmonic current amplitude;

[0079] The calculation of the capacitance deviation based on the fundamental current amplitude and phase and the harmonic current amplitude and phase based on Kirchhoff's law is specifically:

[0080]

[0081] In the formula, It represents the hth harmonic voltage of the A phase of the shunt capacitor busbar, represents the hth harmonic voltage of the parallel capacitor bus B phase, Indicates the hth harmonic voltage phase of the parallel capacitor bus A phase, Indicates the hth harmonic voltage phase of the parallel capacitor bus B phase, represents the hth harmonic current flowing through the A phase of the shunt capacitor device, represents the phase of the hth harmonic current flowing through the A phase of the shunt capacitor device, m represents the change coefficient of the inductive reactance after the A phase reactor fails, and X L represents the fundamental wave rated inductive reactance of the series reactor before the fault, α represents the coefficient of change of the capacitive reactance after the fault of the phase A capacitor, and X C Indicates the fundamental rated capacitive reactance of the shunt capacitor before fault. represents the hth harmonic current flowing through the B phase of the shunt capacitor device, represents the phase of the hth harmonic current flowing through the B phase of the shunt capacitor device, n represents the coefficient of change of the inductive reactance after the B phase reactor fails, β represents the coefficient of change of the capacitive reactance after the B phase capacitor fails, It represents the hth harmonic voltage of the parallel capacitor bus phase C, It represents the hth harmonic voltage of the parallel capacitor bus phase C, represents the hth harmonic current flowing through the C phase of the shunt capacitor device, It represents the phase of the hth harmonic current flowing through the C phase of the parallel capacitor device, p represents the coefficient of change of the inductive reactance after the C phase reactor fails, and γ represents the coefficient of change of the capacitive reactance after the C phase capacitor fails.

[0082] It can be seen from the above description that by calculating the equivalent voltage factor, voltage deviation, harmonic current sum of squares and capacitance deviation data, the abnormality of the reactive power compensation device can be accurately and effectively monitored.

[0083] Furthermore, the judging whether the reactive power compensation device has an overvoltage risk based on the warning threshold library according to the equivalent voltage factor and the voltage deviation, and if so, outputting the overvoltage warning information includes:

[0084] Determining the operating condition of the reactive power compensation device according to the equivalent voltage factor, wherein the operating condition includes an abnormal operating condition;

[0085] If the operating condition is the abnormal operating condition, determining the step order according to the voltage deviation, and acquiring the first overvoltage abnormal threshold and the second overvoltage abnormal threshold corresponding to the step order from the warning threshold library;

[0086] It is determined whether the voltage deviation is continuously within the range formed by the first overvoltage abnormality threshold and the second overvoltage abnormality threshold for a second preset time period. If so, an overvoltage warning threshold is output.

[0087] From the above description, it can be seen that when the operating condition of the reactive compensation device is determined to be an abnormal condition based on the equivalent voltage factor, it is judged whether the voltage deviation continues to be within the range formed by the first overvoltage abnormal threshold and the second overvoltage abnormal threshold for the second preset time period. If so, the overvoltage warning threshold is output to judge the stability of the overvoltage state and achieve accurate warning of overvoltage abnormality.

[0088] Further, judging whether the reactive power compensation device has an overcurrent risk based on the harmonic current square sum based on the warning threshold library, and if so, outputting overcurrent warning information includes:

[0089] Acquire an overcurrent abnormality threshold from the warning threshold library;

[0090] It is determined whether the square sum of the harmonic currents exceeds the overcurrent abnormality threshold, and if so, an overcurrent warning message is output.

[0091] From the above description, it can be seen that based on the harmonic influence mechanism, by judging whether the sum of squares of harmonic currents exceeds the overcurrent abnormal threshold, an early warning of overcurrent status is effectively achieved.

[0092] Further, the method of judging whether the reactive power compensation device has a capacitance deviation abnormality risk based on the capacitance deviation data based on the warning threshold library, and if so, outputting capacitance deviation abnormality warning information includes:

[0093] Obtaining the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart from the early warning threshold library;

[0094] Grouping the capacitance deviation data to obtain grouped capacitance deviation data;

[0095] Calculate the mean and standard deviation of the capacitance deviation data for each group;

[0096] Determine whether there is any group of capacitance deviation data whose mean exceeds the range formed by the upper control line and the lower control line of the mean control diagram. If so, output capacitance deviation abnormal warning information. If not, determine whether there is any group of capacitance deviation data whose standard deviation exceeds the range formed by the upper control line and the lower control line of the standard deviation control diagram. If so, output capacitance deviation abnormal warning information.

[0097] From the above description, it can be seen that calculating the mean and standard deviation of each group of capacitance deviation data and using the mean control chart and the standard deviation control chart to identify capacitance deviation anomalies in the capacitance deviation data is intuitive and accurate.

[0098] Please refer to Figure 2 Another embodiment of the present invention provides an abnormal warning system for a reactive compensation device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, each step in the above-mentioned abnormal warning method for the reactive compensation device is implemented.

[0099] The above-mentioned reactive power compensation device abnormality early warning method and system of the present invention can be applied to reactive power compensation devices, and the following is an explanation through specific implementation methods:

[0100] Please refer to Figure 1 , Figure 3-Figure 6 , Embodiment 1 of the present invention is:

[0101] A reactive power compensation device abnormality early warning method, comprising the steps of:

[0102] S1. Regularly update the warning threshold library, such as Figure 3 As shown, specifically including S11-S19:

[0103] S11. Obtain an equivalent voltage factor and a voltage deviation of the reactive power compensation device in a preset historical time period, and identify a voltage step time and a step number based on the equivalent voltage factor.

[0104] In an optional implementation, the preset time period is one month, and the historical preset time period is the previous month.

[0105] Wherein, the identifying of the voltage step time and the step number based on the equivalent voltage factor comprises:

[0106] Select a moment from the historical preset time period in sequence as the current moment;

[0107] If the equivalent voltage factor at the current moment is greater than 1 and less than or equal to 1.1, and the equivalent voltage factor at the moment before the current moment is less than or equal to 1, then the current moment is marked as a voltage step moment, and the step number is 1;

[0108] If the equivalent voltage factor of the current moment is greater than 1.1, and the equivalent voltage factor of the previous moment before the current moment is less than or equal to 1.1, the current moment is marked as a voltage step moment, and the step number is 1;

[0109] If the equivalent voltage factor of the current moment is greater than 1.1, and the equivalent voltage factor of the previous moment before the current moment is less than or equal to 1, the current moment is marked as a voltage step moment, and the step number is 2;

[0110] Return to execute the step of selecting a moment from the historical preset time period in sequence as the current moment, until every moment in the historical preset time period has been selected as the current moment.

[0111] S12. Select, from the voltage deviations of the reactive power compensation device in the historical preset time period, the voltage deviation within a first preset time length before the voltage step moment and the voltage deviation within a first preset time length after the voltage step moment.

[0112] In an optional implementation, the first preset duration is 12 hours.

[0113] S13. Calculate the average value of the voltage deviation within the first preset time period before the voltage step moment as the first overvoltage abnormal threshold corresponding to the step order, and calculate the voltage deviation within the first preset time period after the voltage step moment as the second overvoltage abnormal threshold corresponding to the step order.

[0114] S14: Update the first overvoltage abnormality threshold and the second overvoltage abnormality threshold to a warning threshold library.

[0115] S15. Select a target equivalent voltage factor that is less than or equal to a first preset value from the equivalent voltage factors of the reactive power compensation device in the historical preset time period, and obtain a fundamental current amplitude corresponding to the target equivalent voltage factor.

[0116] In an optional implementation, the first preset value is 1.

[0117] S16. Calculate an overcurrent abnormality threshold based on the fundamental current amplitude, and update the overcurrent abnormality threshold to the warning threshold library.

[0118] The overcurrent abnormality threshold calculated based on the fundamental current amplitude is specifically:

[0119]

[0120] In the formula, k represents the correction factor. The value of k is mainly based on the consideration that the voltage peak value including all harmonic components should not exceed The relevant requirements of the equivalent conversion, k is recommended to be 0.1125, I 0i represents the fundamental current amplitude on the i-th day, and N represents the number of days in the preset time period.

[0121] S17: Acquire capacitance deviation data of the reactive power compensation device in the historical preset time period.

[0122] In view of the slowly changing characteristics of the capacitance deviation of the reactive compensation device, an abnormal state identification method based on the control chart method is used to carry out early warning.

[0123] S18, based on the capacitance deviation data, using the control chart method to calculate the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart, and using the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart as capacitance deviation abnormality thresholds to update the early warning threshold library, specifically including S181-S189:

[0124] S181 . Group the capacitance deviation data to obtain multiple sample groups.

[0125] Each sample group includes at least 40 samples, and the total number of sample groups is at least 30.

[0126] S182: Calculate the mean and standard deviation of each sample group in the multiple sample groups, and calculate the mean and standard deviation of the multiple sample groups based on the mean and standard deviation of each sample group.

[0127] The calculation of the mean and standard deviation of each sample group in the multiple sample groups is specifically as follows:

[0128]

[0129]

[0130] In the formula, represents the mean of the i-th sample group, n represents the number of samples in each sample group, x ij represents the jth sample in the i-th sample group, S i Represents the standard deviation of the i-th sample group.

[0131] The method of calculating the mean and standard deviation of the plurality of sample groups according to the mean and standard deviation of each sample group is specifically as follows:

[0132]

[0133] In the formula, represents the mean of multiple sample groups, m represents the total number of sample groups, Represents the standard deviation of multiple sample groups.

[0134] S183, calculating the upper control line, the center line and the lower control line of the standard deviation control chart based on the standard deviations of the multiple sample groups, specifically:

[0135]

[0136] In the formula, UCL S represents the upper control line of the standard deviation control chart, B4 represents the first coefficient, CL S Represents the center line of the standard deviation control chart, LCL S represents the lower control line of the standard deviation control chart, and B3 represents the second coefficient.

[0137] When n is greater than 25,

[0138] Therefore, when n=40, B3≈0.6581, B4≈1.3419.

[0139] S184, generating a standard deviation control chart based on the upper control line, the center line and the lower control line of the standard deviation control chart, and using the capacitance deviation data to mark points in the standard deviation control chart.

[0140] S185, determining whether the sample points in the standard deviation control chart are stable, if not, removing the unstable sample points, and adding the same number of new sample points as the unstable sample points into the capacitance deviation data, and regenerating the standard deviation control chart until the sample points in the standard deviation control chart are stable, such as Figure 4 shown.

[0141] Wherein, judging whether the sample points in the standard deviation control chart are stable includes:

[0142] Determine whether there are a first preset number of consecutive sample points in the standard deviation control chart within the range formed by the upper control line and the lower control line of the standard deviation control chart. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a second preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a second preset value. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a third preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a third preset value. If so, determine that the sample points in the standard deviation control chart are stable. If so, determine that the sample points in the standard deviation control chart are unstable.

[0143] In an optional implementation, the first preset number is 25, the second preset number is 35, the second preset value is 1, the third preset number is 100, and the third preset value is 2.

[0144] S186, calculating the upper control line, center line and lower control line of the mean control chart based on the means and standard deviations of the multiple sample groups, specifically:

[0145]

[0146] In the formula, represents the upper control line of the mean control chart, and A3 represents the third coefficient.

[0147] When n is greater than 25,

[0148] S187, generating a mean control chart based on the upper control line, the center line and the lower control line of the mean control chart, and using the capacitance deviation data to mark points in the mean control chart.

[0149] S188, determining whether the sample points in the mean control graph are stable, if not, removing the unstable sample points, and adding the same number of new sample points as the unstable sample points into the capacitance deviation data, and then regenerating the mean control graph until the sample points in the mean control graph are stable.

[0150] Among them, the specific method of judging whether the sample points in the mean control chart are stable is consistent with the method of judging whether the sample points in the standard deviation control chart are stable, which will not be repeated here.

[0151] S189, updating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart as capacitance deviation abnormality thresholds to the early warning threshold library.

[0152] like Figure 6 As shown, Figure 6 A schematic diagram of a control chart is given, which includes an upper control line, a middle line and a lower control line.

[0153] S19, returning to execute S11 at intervals of the preset time period.

[0154] Specifically, the process returns to S11 at intervals of one month, that is, the warning threshold library is updated once a month.

[0155] S2. Obtain the equivalent voltage factor, voltage skewness, harmonic current sum of squares and capacitance deviation data (i.e., advanced statistical indicators) of the reactive power compensation device, such as Figure 3 As shown, specifically including S21-S26:

[0156] S21, collecting the phase voltage of the access bus of the reactive power compensation device, the line voltage of the access bus and the instantaneous value of the outgoing line current.

[0157] S22. Calculate the fundamental phase voltage amplitude and phase, fundamental line voltage amplitude and phase, fundamental current amplitude and phase, and harmonic current amplitude and phase (i.e., basic state quantity indicators) based on fast Fourier transform according to the phase voltage of the access bus, the line voltage of the access bus, and the instantaneous value of the outgoing line current.

[0158] S23, calculating an equivalent voltage factor according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase, specifically:

[0159]

[0160] Where U e Indicates the equivalent voltage factor, U a1 Indicates the effective value of the fundamental phase voltage of phase A, U b1 Indicates the effective value of the fundamental phase voltage of phase B, U c1 Indicates the effective value of the fundamental phase voltage of phase C, U ab1 Indicates the effective value of the fundamental line voltage between phase A and phase B, U bc1 Indicates the effective value of the fundamental line voltage between phase B and phase C, U ca1 It represents the effective value of the fundamental line voltage between phase C and phase A, and U0 represents the rated voltage of the reactive compensation device.

[0161] S24, calculating the voltage deviation based on the equivalent voltage factor, specifically:

[0162]

[0163] Where δ represents the voltage skewness, E(·) represents the expected function, and μ represents the average value of the equivalent voltage.

[0164] Voltage skewness is a high-order statistic that describes the symmetry of the distribution of voltage variable values. If the voltage skewness is negative, it means that the sample is biased to the left. If the voltage skewness is 0, it means that the sample is symmetrically distributed. If the voltage skewness is positive, it means that the sample is biased to the right. The larger the absolute value, the more serious the deviation. There are many definitions of skewness. The skewness of normal distribution and all symmetrical distributions is 0.

[0165] S25, calculating the sum of squares of harmonic currents based on the harmonic current amplitudes and phases, such as Figure 5 As shown, specifically:

[0166]

[0167] Where, I represents the square sum of harmonic currents, I Ch Indicates the hth harmonic current amplitude.

[0168] S26, calculating the capacitance deviation based on the fundamental current amplitude and phase and the harmonic current amplitude and phase based on Kirchhoff's law, that is, taking the fundamental and a certain high-content harmonic to establish simultaneous equations, specifically:

[0169]

[0170] In the formula, It represents the hth harmonic voltage of the A phase of the shunt capacitor busbar, It represents the hth harmonic voltage of the parallel capacitor bus B phase, h=1, 2, 3…, Indicates the hth harmonic voltage phase of the parallel capacitor bus A phase, Indicates the hth harmonic voltage phase of the parallel capacitor bus B phase, represents the hth harmonic current flowing through the A phase of the shunt capacitor device, represents the phase of the hth harmonic current flowing through the A phase of the shunt capacitor device, m represents the change coefficient of the inductive reactance after the A phase reactor fails, and X L represents the fundamental wave rated inductive reactance of the series reactor before the fault, α represents the coefficient of change of the capacitive reactance after the fault of the phase A capacitor, and X C Indicates the fundamental rated capacitive reactance of the shunt capacitor before fault. It represents the hth harmonic current flowing through the B phase of the shunt capacitor device. When h=1, it is the fundamental current. represents the phase of the hth harmonic current flowing through the B phase of the shunt capacitor device, n represents the coefficient of change of the inductive reactance after the B phase reactor fails, β represents the coefficient of change of the capacitive reactance after the B phase capacitor fails, It represents the hth harmonic voltage of the parallel capacitor bus phase C, It represents the hth harmonic voltage of the parallel capacitor bus phase C, represents the hth harmonic current flowing through the C phase of the shunt capacitor device, It represents the phase of the hth harmonic current flowing through the C phase of the parallel capacitor device, p represents the coefficient of change of the inductive reactance after the C phase reactor fails, and γ represents the coefficient of change of the capacitive reactance after the C phase capacitor fails.

[0171] Among them, α, β, and γ are the three-phase capacitance deviations to be determined. At the hth harmonic, the capacitive reactance of the parallel capacitor is X Ch =X C / h, series reactor reactance X Lh =hX L .

[0172] S3, based on the warning threshold library, judging whether the reactive power compensation device has an overvoltage risk according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information, such as Figure 5 As shown, specifically including S31-S33:

[0173] S31. Determine the operating condition of the reactive power compensation device according to the equivalent voltage factor, wherein the operating condition includes an abnormal operating condition and a normal operating condition, and the abnormal operating condition includes a first abnormal operating condition, a second abnormal operating condition and a third abnormal operating condition.

[0174] Specifically, the national standard GB / T 11024.1-2019 stipulates the long-term operating voltage of parallel capacitors. The equipment tolerance capacity depends on the amplitude and duration of the power frequency overvoltage. If the equivalent voltage factor is in the range of 1 to 1.1, the operating condition of the reactive compensation device is determined to be the first abnormal condition. If the equivalent voltage factor is in the range of 1.1 to 1.15, the operating condition of the reactive compensation device is determined to be the second abnormal condition. If the equivalent voltage factor is 1.15, the operating condition of the reactive compensation device is determined to be the third abnormal condition. If neither of them belongs to the above range, the operating condition of the reactive compensation device is determined to be the normal condition.

[0175] S32. If the operating condition is the abnormal operating condition, determine the step order according to the voltage deviation, and obtain a first overvoltage abnormal threshold and a second overvoltage abnormal threshold corresponding to the step order from the warning threshold library.

[0176] S33, determining whether the voltage deviation is continuously within the range formed by the first overvoltage abnormality threshold and the second overvoltage abnormality threshold for a second preset time period; if so, outputting an overvoltage warning threshold.

[0177] In an optional implementation, the second preset duration is 15 minutes.

[0178] In an optional implementation manner, after S31, the following steps may also be included:

[0179] If the operating condition is the first abnormal operating condition for a cumulative third preset time, an overvoltage alarm message is output;

[0180] If the operating condition is the second abnormal operating condition for a cumulative fourth preset time, an overvoltage alarm message is output;

[0181] If the operating condition is the third abnormal operating condition, an overvoltage alarm message is output.

[0182] In an optional implementation, the third preset time is 12 hours, and the fourth preset time is 5 minutes. In addition to being able to warn the reactive power compensation device with signs of abnormal overvoltage, it can also warn the reactive power compensation device that has already experienced abnormal overvoltage, ensuring that the staff can handle the fault in time.

[0183] S4: Based on the warning threshold library and the square sum of the harmonic currents, determine whether the reactive power compensation device has an overcurrent risk. If so, output overcurrent warning information, such as Figure 5 As shown, specifically including S41-S42:

[0184] S41. Obtain an abnormal overcurrent threshold from the warning threshold library.

[0185] S42: Determine whether the sum of the squares of the harmonic currents exceeds the overcurrent abnormal threshold, and if so, output overcurrent warning information.

[0186] The national standard GB / T 11024.1-2019 stipulates that the capacitor unit should be able to operate continuously at a current root mean square value of 1.3 times the current generated by the unit at the rated sinusoidal voltage and rated frequency. In an optional embodiment, it may also include:

[0187] The effective current value of the reactive power compensation device is obtained, and it is determined whether the effective current value exceeds a preset multiple of the rated current. If so, an overcurrent alarm message is output, so as to give a timely alarm for overcurrent and facilitate timely maintenance.

[0188] S5. Based on the warning threshold library and the capacitance deviation data, determine whether the reactive power compensation device has a capacitance deviation abnormality risk. If so, output capacitance deviation abnormality warning information, such as Figure 5 As shown, specifically including S51-S54:

[0189] S51. Obtaining an upper control line and a lower control line of the standard deviation control chart and an upper control line and a lower control line of the mean control chart from the early warning threshold library.

[0190] S52: Group the capacitance deviation data to obtain grouped capacitance deviation data.

[0191] S53, calculating the mean and standard deviation of the capacitance deviation data of each group.

[0192] S54. Determine whether there is any group of capacitance deviation data whose mean value exceeds the range formed by the upper control line and the lower control line of the mean control diagram. If so, output capacitance deviation abnormal warning information. If not, determine whether there is any group of capacitance deviation data whose standard deviation exceeds the range formed by the upper control line and the lower control line of the standard deviation control diagram. If so, output capacitance deviation abnormal warning information.

[0193] The present invention constructs a warning threshold library, and the warning threshold can be automatically updated regularly by means of data correlation analysis and the like, thereby ensuring accurate warning of abnormal conditions; and proposes an overvoltage warning technology for a reactive compensation device based on data statistical learning, by judging whether the voltage deviation is stable within a certain threshold, to judge the stability of the overvoltage state, and based on actual operation data statistics, learn the abnormal thresholds under two types of voltage step amplitudes in adjacent / indirect operation intervals, thereby realizing accurate warning of the overvoltage state; in addition, the overcurrent warning technology for a reactive compensation device based on the harmonic influence mechanism, by deriving the capacitor overcurrent verification formula under harmonic conditions, obtains the allowable level of harmonic current, thereby realizing early warning of the overcurrent state; and also proposes a capacitor deviation warning technology for a reactive compensation device based on a statistical control chart, by combining recent historical capacitor deviation monitoring data to learn the abnormal threshold of the capacitor deviation trend, thereby realizing accurate identification of the abnormal state of the capacitor deviation trend.

[0194] Please refer to Figure 2 , Embodiment 2 of the present invention is:

[0195] A reactive power compensation device abnormality warning system comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, each step of the reactive power compensation device abnormality warning method in the first embodiment is implemented.

[0196] In summary, the present invention provides a method and system for abnormal warning of reactive power compensation device, which regularly updates the warning threshold library, and judges whether the reactive power compensation device has an overvoltage risk based on the equivalent voltage factor and voltage deviation based on the warning threshold library. If so, the overvoltage warning information is output; judges whether the reactive power compensation device has an overcurrent risk based on the harmonic current sum of squares based on the warning threshold library, and if so, the overcurrent warning information is output; judges whether the reactive power compensation device has an abnormal capacitance deviation risk based on the capacitance deviation data based on the warning threshold library, and if so, the capacitance deviation abnormality warning information is output, thereby warning of overvoltage risk through equivalent voltage factor and voltage deviation, warning of overcurrent risk through harmonic current sum of squares, and warning of capacitance deviation abnormality risk through capacitance deviation data, which can more effectively and reliably warn of overvoltage, overcurrent and capacitance of the reactive power compensation device. Deviation anomalies are warned, and the warning threshold library is updated regularly to ensure that the thresholds in the warning threshold library can be updated in real time according to recent historical data, ensuring accurate warning of abnormal risks, thereby achieving more accurate and reliable abnormal warning of reactive power compensation devices; in addition, the equivalent voltage factor and voltage deviation of the reactive power compensation device in the historical preset time period are obtained, and the overvoltage anomaly threshold is calculated based on them and updated to the warning threshold library, the overcurrent anomaly threshold is calculated based on the fundamental current amplitude corresponding to the target equivalent voltage factor, and it is updated to the warning threshold library, and the control chart method is used to calculate the upper control line and lower control line of the standard deviation control chart and the upper control line and lower control line of the mean control chart as the capacitance deviation anomaly threshold to update to the warning threshold library according to the capacitance deviation data of the reactive power compensation device in the historical preset time period, and more scientific and reasonable warning thresholds for overvoltage, overcurrent and capacitance deviation anomalies are determined.

[0197] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A reactive power compensation device abnormality early warning method, characterized in that: Includes steps: Regularly update the warning threshold library; Obtain the equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device; Based on the warning threshold library, judging whether the reactive power compensation device has an overvoltage risk according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information; Based on the warning threshold library, judging whether the reactive power compensation device has an overcurrent risk according to the square sum of the harmonic currents, and if so, outputting overcurrent warning information; Based on the warning threshold library, it is determined according to the capacitance deviation data whether the reactive power compensation device has a capacitance deviation abnormality risk. If so, capacitance deviation abnormality warning information is output.

2. The method for abnormal warning of reactive power compensation device according to claim 1, characterized in that: The periodic updating of the warning threshold library includes: Acquire the equivalent voltage factor and voltage deviation of the reactive power compensation device in a historical preset time period, and identify the voltage step time and step number based on the equivalent voltage factor; Selecting, from the voltage deviations of the reactive power compensation device in the historical preset time period, the voltage deviation within a first preset time length before the voltage step moment and the voltage deviation within a first preset time length after the voltage step moment; Calculating an average value of the voltage deviation within a first preset time length before the voltage step moment as a first overvoltage abnormal threshold value corresponding to the step number, and calculating an average value of the voltage deviation within a first preset time length after the voltage step moment as a second overvoltage abnormal threshold value corresponding to the step number; Updating the first overvoltage abnormality threshold and the second overvoltage abnormality threshold to a warning threshold library; Selecting a target equivalent voltage factor that is less than or equal to a first preset value from the equivalent voltage factors of the reactive power compensation device in the historical preset time period, and acquiring a fundamental current amplitude corresponding to the target equivalent voltage factor; Calculate an overcurrent abnormality threshold based on the fundamental current amplitude, and update the overcurrent abnormality threshold to the warning threshold library; Acquiring capacitance deviation data of the reactive power compensation device in the historical preset time period; Calculating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart using the control chart method based on the capacitance deviation data, and updating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart as capacitance deviation abnormality thresholds to the early warning threshold library; The step of obtaining the equivalent voltage factor and voltage deviation of the reactive power compensation device in the historical preset time period is performed again at intervals of the preset time period.

3. The method for abnormal warning of reactive power compensation device according to claim 2, characterized in that: The method of calculating the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart based on the capacitance deviation data using the control chart method includes: Grouping the capacitance deviation data to obtain multiple sample groups; Calculating the mean and standard deviation of each sample group in the multiple sample groups, and calculating the mean and standard deviation of the multiple sample groups based on the mean and standard deviation of each sample group; Calculate the upper control line, center line and lower control line of the standard deviation control chart based on the standard deviations of the multiple sample groups; Generate a standard deviation control chart based on the upper control line, the center line and the lower control line of the standard deviation control chart, and use the capacitance deviation data to mark points in the standard deviation control chart; Determine whether the sample points in the standard deviation control chart are stable. If not, remove the unstable sample points, add the same number of new sample points as the unstable sample points into the capacitance deviation data, and regenerate the standard deviation control chart until the sample points in the standard deviation control chart are stable. Calculate the upper control line, center line and lower control line of the mean control chart based on the means and standard deviations of the plurality of sample groups; Generate a mean control chart based on the upper control line, the center line and the lower control line of the mean control chart, and use the capacitance deviation data to mark points in the mean control chart; Determine whether the sample points in the mean control graph are stable. If not, remove the unstable sample points, add the same number of new sample points as the unstable sample points into the capacitance deviation data, and regenerate the mean control graph until the sample points in the mean control graph are stable.

4. The method for abnormal warning of reactive power compensation device according to claim 3 is characterized in that: The determining whether the sample points in the standard deviation control chart are stable comprises: Determine whether there are a first preset number of consecutive sample points in the standard deviation control chart within the range formed by the upper control line and the lower control line of the standard deviation control chart. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a second preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a second preset value. If so, determine that the sample points in the standard deviation control chart are stable. If not, determine whether the number of sample points in a third preset number of consecutive sample points that exceed the range formed by the upper control line and the lower control line of the standard deviation control chart is less than or equal to a third preset value. If so, determine that the sample points in the standard deviation control chart are stable. If so, determine that the sample points in the standard deviation control chart are unstable.

5. The method for abnormal warning of reactive power compensation device according to claim 1, characterized in that: The obtaining of equivalent voltage factor, voltage deviation, harmonic current square sum and capacitance deviation data of the reactive power compensation device comprises: Collect the phase voltage of the access bus of the reactive power compensation device, the line voltage of the access bus and the instantaneous value of the outgoing line current; Calculate the fundamental phase voltage amplitude and phase, the fundamental line voltage amplitude and phase, the fundamental current amplitude and phase, and the harmonic current amplitude and phase based on fast Fourier transform according to the phase voltage of the access bus, the line voltage of the access bus, and the instantaneous value of the outgoing line current; Calculating an equivalent voltage factor according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase; Calculating a voltage deviation based on the equivalent voltage factor; Calculating a sum of squares of harmonic currents based on the harmonic current amplitudes and phases; Capacitance deviation is calculated based on Kirchhoff's law based on the fundamental current amplitude and phase and the harmonic current amplitude and phase.

6. The method for abnormal warning of reactive power compensation device according to claim 5, characterized in that: The equivalent voltage factor is calculated according to the fundamental phase voltage amplitude and phase and the fundamental line voltage amplitude and phase as follows: Where U e Indicates the equivalent voltage factor, U a1 Indicates the effective value of the fundamental phase voltage of phase A, U b1 Indicates the effective value of the fundamental phase voltage of phase B, U c1 Indicates the effective value of the fundamental phase voltage of phase C, U ab1 Indicates the effective value of the fundamental line voltage between phase A and phase B, U bc1 Indicates the effective value of the fundamental line voltage between phase B and phase C, U ca1 It represents the effective value of the fundamental line voltage between phase C and phase A, and U0 represents the rated voltage of the reactive compensation device; The voltage deviation is calculated based on the equivalent voltage factor as follows: In the formula, δ represents the voltage skewness, E(·) represents the expected function, and μ represents the average value of the equivalent voltage; Calculating the sum of squares of harmonic currents based on the harmonic current amplitudes and phases comprises: Where, I represents the square sum of harmonic currents, I Ch Indicates the hth harmonic current amplitude; The calculation of the capacitance deviation based on the fundamental current amplitude and phase and the harmonic current amplitude and phase based on Kirchhoff's law is specifically: In the formula, It represents the hth harmonic voltage of the A phase of the shunt capacitor busbar, represents the hth harmonic voltage of the parallel capacitor bus B phase, Indicates the hth harmonic voltage phase of the parallel capacitor bus A phase, Indicates the hth harmonic voltage phase of the parallel capacitor bus B phase, represents the hth harmonic current flowing through the A phase of the shunt capacitor device, represents the phase of the hth harmonic current flowing through the A phase of the shunt capacitor device, m represents the change coefficient of the inductive reactance after the A phase reactor fails, and X L represents the fundamental wave rated inductive reactance of the series reactor before the fault, α represents the coefficient of change of the capacitive reactance after the fault of the phase A capacitor, and X C Indicates the fundamental rated capacitive reactance of the shunt capacitor before fault. represents the hth harmonic current flowing through the B phase of the shunt capacitor device, represents the phase of the hth harmonic current flowing through the B phase of the shunt capacitor device, n represents the coefficient of change of the inductive reactance after the B phase reactor fails, β represents the coefficient of change of the capacitive reactance after the B phase capacitor fails, It represents the hth harmonic voltage of the parallel capacitor bus phase C, It represents the hth harmonic voltage of the parallel capacitor bus phase C, represents the hth harmonic current flowing through the C phase of the shunt capacitor device, It represents the phase of the hth harmonic current flowing through the C phase of the parallel capacitor device, p represents the coefficient of change of the inductive reactance after the C phase reactor fails, and γ represents the coefficient of change of the capacitive reactance after the C phase capacitor fails.

7. The method for abnormal warning of reactive power compensation device according to claim 2, characterized in that: The judging whether the reactive power compensation device has an overvoltage risk based on the warning threshold library according to the equivalent voltage factor and the voltage deviation, and if so, outputting overvoltage warning information includes: Determining the operating condition of the reactive power compensation device according to the equivalent voltage factor, wherein the operating condition includes an abnormal operating condition; If the operating condition is the abnormal operating condition, determining the step order according to the voltage deviation, and acquiring the first overvoltage abnormal threshold and the second overvoltage abnormal threshold corresponding to the step order from the warning threshold library; It is determined whether the voltage deviation is continuously within the range formed by the first overvoltage abnormality threshold and the second overvoltage abnormality threshold for a second preset time period. If so, an overvoltage warning threshold is output.

8. The method for abnormal warning of reactive power compensation device according to claim 2, characterized in that: The judging whether the reactive power compensation device has an overcurrent risk based on the harmonic current square sum based on the warning threshold library, and if so, outputting overcurrent warning information includes: Acquire an overcurrent abnormality threshold from the warning threshold library; It is determined whether the square sum of the harmonic currents exceeds the overcurrent abnormal threshold, and if so, an overcurrent warning message is output.

9. The method for abnormal warning of reactive power compensation device according to claim 2, characterized in that: The method of judging whether the reactive power compensation device has a capacitance deviation abnormality risk based on the warning threshold library according to the capacitance deviation data, and if so, outputting capacitance deviation abnormality warning information includes: Obtaining the upper control line and the lower control line of the standard deviation control chart and the upper control line and the lower control line of the mean control chart from the early warning threshold library; Grouping the capacitance deviation data to obtain grouped capacitance deviation data; Calculate the mean and standard deviation of the capacitance deviation data for each group; Determine whether there is any group of capacitance deviation data whose mean exceeds the range formed by the upper control line and the lower control line of the mean control diagram. If so, output capacitance deviation abnormal warning information. If not, determine whether there is any group of capacitance deviation data whose standard deviation exceeds the range formed by the upper control line and the lower control line of the standard deviation control diagram. If so, output capacitance deviation abnormal warning information.

10. A reactive power compensation device abnormality warning system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, each step of the abnormal warning method for reactive power compensation device described in any one of claims 1 to 9 is implemented.

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