Method, system and device for identifying insulation performance of capacitive voltage transformer based on metering data, and medium

Abstract

This invention discloses a method, system, device, and medium for identifying the insulation performance of capacitive voltage transformers based on metering data. The method first acquires the substation's internal electrical energy data (power generation, power consumption, and power transmission) and the operating data of each capacitive voltage transformer (primary current to ground, and voltages of each secondary winding). If the power generation is not equal to the sum of power consumption and power transmission, an electrical balance anomaly is identified. Current anomaly judgment is performed based on the primary current to ground of the same three-phase capacitive voltage transformer. The deviations in the protection, measurement, and zero-sequence winding voltages of the same group of capacitive voltage transformers are determined using the secondary metering winding voltage as a benchmark. If the deviation exceeds a threshold, a voltage anomaly is identified. Capacitive voltage transformers exhibiting both current and voltage anomalies are identified as having insulation performance anomalies. This invention achieves online insulation performance identification without power outages, improving identification accuracy and power supply reliability.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment testing technology, and in particular to a method, system, device and medium for identifying the insulation performance of capacitive voltage transformers based on metering data. Background Technology

[0002] Voltage measurement data is the core foundation for power grid operation monitoring, condition assessment, and dispatching decisions. Its accuracy and reliability directly affect the effectiveness of power system control strategies and operational safety. Capacitive voltage transformers, due to their advantages such as good economy, stable operation, and excellent insulation performance, are widely used in power metering, measurement, and relay protection at voltage levels of 110kV and above. With the continuous expansion of my country's power grid, the number of capacitive voltage transformers in operation has increased rapidly. Equipment anomalies and faults caused by insulation aging and capacitance drift are showing an increasing trend year by year, posing a serious threat to the safe and stable operation of the power grid.

[0003] Currently, the insulation performance testing of traditional capacitive voltage transformers mainly relies on preventive testing in substations, judging the insulation status by measuring parameters such as dielectric loss and capacitance. These methods mostly require the equipment to be de-energized, which not only affects power supply reliability but also makes it difficult to achieve real-time sensing and continuous monitoring of the insulation status of equipment during operation. While existing infrared thermography can be performed under energized conditions, it can only reflect localized overheating defects and cannot accurately characterize early, latent anomalies such as insulation degradation and changes in capacitance parameters.

[0004] In summary, traditional detection methods suffer from drawbacks such as high dependence on power outages, poor real-time performance, delayed anomaly identification, and limited coverage, failing to meet the power grid's needs for online monitoring, accurate early warning, and condition-based operation and maintenance of capacitive voltage transformers' insulation performance. Therefore, there is an urgent need for a method that can accurately identify the insulation performance of capacitive voltage transformers in real time, without requiring power outages and based on existing operational metering data, to overcome the shortcomings of existing technologies and improve the operation and maintenance level of capacitive voltage transformers and the reliability of power grid supply. Summary of the Invention

[0005] Therefore, it is necessary to propose a method, system, equipment, and medium for identifying the insulation performance of capacitive voltage transformers based on metering data to address the above problems.

[0006] A method for identifying the insulation performance of a capacitive voltage transformer based on metering data, the method comprising: Acquire the internal electrical energy data of the target substation, as well as the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measuring winding voltage and secondary zero-sequence voltage winding voltage. If the power generation is not equal to the sum of the power consumption and the power output, then the target substation is determined to have an abnormal power balance. When there is an abnormal power balance in the target substation, the current anomaly is judged based on the primary ground current of the same group of capacitive voltage transformers in the target substation, and several groups of capacitive voltage transformers with abnormal current are obtained. The group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus. Using the secondary metering winding voltage as a reference, the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers are determined. If any voltage deviation exceeds a preset threshold, it is determined to be a voltage abnormality. Capacitive voltage transformers that simultaneously exhibit current and voltage abnormalities are considered to have abnormal insulation performance.

[0007] Specifically, the current anomaly detection based on the primary-to-ground current of the same group of capacitive voltage transformers within the target substation includes: Calculate the vector sum of the primary-to-ground currents of the three-phase capacitive voltage transformers A, B, and C in the same group of capacitive voltage transformers; If the capacitive voltage transformers in the same group are from the same batch, then determine whether the absolute value of the vector sum exceeds the first preset threshold; if so, then determine that the current is abnormal. If the capacitive voltage transformers in the same group are not from the same batch or model, and the vector sum is a first fixed value under normal operating conditions, then it is determined whether the vector sum is within the preset first fixed value range; otherwise, it is determined to be an abnormal current.

[0008] Specifically, the method of determining current anomalies based on the primary-to-ground current of the same group of capacitive voltage transformers within the target substation when there is an abnormal power balance at the target substation includes: Calculate the absolute value or ratio of the difference between the primary current to ground of phase A capacitive voltage transformer and the primary current to ground of phase B capacitive voltage transformer, and use this as the first variable. Calculate the absolute value or ratio of the difference between the primary current to ground of phase A capacitive voltage transformer and the primary current to ground of phase C capacitive voltage transformer, and use it as the second variable. Calculate the absolute value or ratio of the difference between the primary current to ground of phase B capacitive voltage transformer and the primary current to ground of phase C capacitive voltage transformer, and use it as the third variable. The first change, the second change, and the third change are respectively formed into time series; Calculate the difference between the value of the next time step and the value of the previous time step in each time series, and determine whether the difference exceeds a second preset threshold. If so, it is determined to be an abnormal current.

[0009] The step of comparing the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers with the secondary metering winding voltage as a reference, and determining that any voltage deviation exceeds a first preset threshold as an abnormal voltage and identifying the capacitive voltage transformer with abnormal insulation performance, further includes: The zero-sequence metering voltage is determined by the vector sum of the secondary metering winding voltages of the A, B, and C phase capacitive voltage transformers in the same group. Based on the zero-sequence metering voltage, a voltage anomaly is determined for a group of capacitive voltage transformers.

[0010] Specifically, the step of determining voltage anomalies in a set of capacitive voltage transformers based on the zero-sequence metering voltage includes: Determine whether the absolute value of the zero-sequence metering voltage exceeds the third preset threshold. If it does, the voltage is determined to be abnormal.

[0011] The preset thresholds include a fourth preset threshold and a fifth preset threshold. The step of determining the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers, based on the secondary metering winding voltage, and determining that any voltage deviation exceeds a preset threshold, is considered a voltage anomaly. Capacitive voltage transformers exhibiting both current and voltage anomalies are classified as capacitive voltage transformers with insulation performance abnormalities. Specifically, this includes: Using the secondary metering winding voltages of the three-phase capacitive voltage transformers A, B, and C as references, calculate the differences between the secondary protection winding voltage and the secondary measurement winding voltage and the corresponding references. For any phase, determine whether the difference between the voltage of the secondary protection winding and the voltage of the secondary measurement winding of the current phase and the corresponding reference exceeds the fourth preset threshold, and whether the voltage of the secondary zero-sequence voltage winding exceeds the fifth preset threshold. If so, it is determined that the voltage of the current phase is abnormal. Capacitive voltage transformers that currently exhibit both current and voltage anomalies are considered to have insulation performance defects.

[0012] The process of determining the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers, based on the secondary metering winding voltage, and determining that any voltage deviation exceeds a preset threshold as a voltage anomaly, further includes: [Further details on the process of determining capacitive voltage transformers with both current and voltage anomalies as having insulation performance anomalies]. The capacitive voltage transformer with abnormal insulation performance was tested and verified in the field under power outage conditions.

[0013] An insulation performance identification system for capacitive voltage transformers based on metering data, the system comprising: The data acquisition module is used to acquire the internal electrical energy data of the target substation and the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage. The power balance anomaly detection module is used to determine that the target substation has a power balance anomaly if the power generation is not equal to the sum of the power consumption and the power transmission. The current anomaly judgment module is used to judge the current anomaly based on the primary ground current of the same group of capacitive voltage transformers in the target substation when there is an abnormal power balance in the target substation. It obtains several groups of capacitive voltage transformers with current anomalies. The group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus. The insulation performance abnormality identification module is used to determine the voltage deviation of the secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers based on the secondary metering winding voltage. If any voltage deviation exceeds a first preset threshold, it is determined to be a voltage abnormality. Capacitive voltage transformers that have both current abnormality and voltage abnormality are regarded as capacitive voltage transformers with insulation performance abnormalities.

[0014] A computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method described above.

[0015] A computer device includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method described above.

[0016] The embodiments of the present invention have the following beneficial effects: Early warning of insulation faults can be achieved by determining the power balance within the target substation (power generation equals the sum of power consumption and power transmission). This eliminates the need for power outage tests to detect system-level anomalies, significantly improving power supply reliability and avoiding the decline in grid stability caused by frequent power outages.

[0017] Furthermore, by using the primary-to-ground current of the same group of capacitive voltage transformers within the target substation, the current anomaly of a group of capacitive voltage transformers can be determined, and the group of capacitive voltage transformers with the current anomaly can be accurately located.

[0018] Furthermore, using the secondary metering winding voltage as a benchmark, the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers are compared to eliminate interference from non-core faults such as loose secondary circuit wiring, thus pinpointing the fault to a single capacitive voltage transformer.

[0019] This invention forms a logical closed loop through the above three criteria, and realizes online identification of insulation performance based on electrical energy and capacitive voltage transformer operation data. It does not require power outages, avoids blind testing of all capacitive voltage transformers in the station, and uses high-precision secondary metering winding voltage as a benchmark to sensitively identify insulation degradation. It is applicable to equipment of the same batch and different batches, improving identification accuracy and power supply reliability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] in: Figure 1 This is a flowchart illustrating an embodiment of a method for identifying the insulation performance of a capacitive voltage transformer based on metering data provided by the present invention. Figure 2 This is a flowchart illustrating another embodiment of the method for identifying the insulation performance of a capacitive voltage transformer based on metering data provided by the present invention. Figure 3 This data represents the daily total electricity consumption, plant power consumption, and power loss of a certain power plant from June 20 to September 16. Figure 4 This is a schematic diagram of an embodiment of a capacitive voltage transformer insulation performance identification system based on metering data provided by the present invention. Figure 5 A schematic diagram of the structure of an embodiment of the device provided by the present invention; Figure 6 A schematic diagram of the structure of an embodiment of the medium provided by the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, Figure 1 This is a flowchart illustrating an embodiment of a method for identifying the insulation performance of a capacitive voltage transformer based on metering data provided by the present invention. The method includes: S101: Obtain the internal energy data of the target substation, as well as the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measuring winding voltage and secondary zero-sequence voltage winding voltage.

[0024] For example, the electrical energy information of the line or bus where the capacitive voltage transformer is located is obtained through an electrical energy data platform, including the generator's power generation or output, power consumption, and power output.

[0025] The substation operation support system acquires the ground current data of the primary side of all capacitive voltage transformers within the substation, denoted as i. a1 i b1 i c1 i a2 i b2 i c2 、、·····、, respectively correspond to the A, B, and C phases of different lines or busbars.

[0026] The secondary metering winding voltage u of the phase A capacitive voltage transformer is obtained through the real-time monitoring system. jl-a1 Secondary protection winding voltage u bh-a1 Secondary measurement of winding voltage u cl-a1 and the secondary zero-sequence voltage winding voltage u lx-a1 Similarly, obtain the data for phase B and phase C.

[0027] S102: If the power generation is not equal to the sum of the power consumption and the power output, then the target substation is determined to have an abnormal power balance.

[0028] For example, a power balance determination is performed based on the collected data on power generation, power consumption, and power transmission: If the power generation is not equal to the sum of the power consumption and the power output, the target substation is determined to have an abnormal power balance and enters the current anomaly detection stage.

[0029] S103: When there is an abnormal power balance in the target substation, the current anomaly is judged based on the primary ground current of the same group of capacitive voltage transformers in the target substation, and several groups of capacitive voltage transformers with abnormal current are obtained. A group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus.

[0030] For example, the deterioration of the insulation performance of a capacitive voltage transformer can cause changes in its equivalent capacitance, which in turn affects its primary-side capacitive current to ground. By analyzing the primary-to-ground currents of three-phase capacitive voltage transformers A, B, and C in the same group (same line or busbar), groups with abnormal current characteristics can be identified.

[0031] In a specific implementation scenario, under the condition of abnormal power balance in the target substation, for each group of capacitive voltage transformers in the substation, calculate the vector sum of the primary-to-ground currents of phases A, B, and C, i.e., the zero-sequence to-ground current: i 10 =i a1 +i b1 +i c1 .

[0032] If the capacitive voltage transformers in this group are from the same batch and of the same model, then during normal operation... 10 ≈0, set the first preset threshold I th1 If |i 10 |>I th1 If the current is abnormal, it is determined to be an abnormal current. The range of the first preset threshold is [...]. 0.05mA, +0.05mA).

[0033] If they are not from the same batch or model, i will operate normally. 10 The first fixed value I fix The first fixed value is the value measured during normal operation, and the range of the first fixed value is set to [I]. fix 0.05,I fix If the value exceeds +0.05, it is considered an abnormal current.

[0034] In another specific implementation scenario, for each group of capacitive voltage transformers, the change in primary current to ground between the same phases is calculated. Taking phases A and B as an example, this can be calculated in two ways: the absolute value of the difference or the percentage ratio. .

[0035] Similarly, the absolute value or percentage ratio of the difference between A and C: .

[0036] The absolute value or percentage ratio of the difference between phases B and C: .

[0037] Each change (e.g., Δi) a1 b1 Arranged in chronological order, they form a time series.

[0038] When the equipment is in a stable state, these changes in the time series should fluctuate slightly around a fixed value. The difference between the value at a later time point and the value at the previous time point (i.e., the first-order difference) is calculated, and it is determined whether this difference exceeds a preset second threshold. The range of the second preset threshold is [ ]. 0.05mA, +0.05mA).

[0039] For example, for the sequence Δi a1 b1 (t), calculate Δ′=∣Δi a1 b1 (t) Δi a1 b1 (t 1) |。 If Δ′> This indicates a sudden change in the relative current relationship, suggesting an anomaly in the current of this group of capacitive voltage transformers. The three change sequences (Δi) a1 b1 ,Δi a1 c1 ,Δi b1 c1 If any sequence in the sequence is determined to be abnormal, it is considered that the current of the capacitive voltage transformer group is abnormal.

[0040] S104: Based on the secondary metering winding voltage, determine the voltage deviation of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers. If any voltage deviation exceeds the preset threshold, it is judged as a voltage abnormality. Capacitive voltage transformers that have both current and voltage abnormalities are regarded as capacitive voltage transformers with insulation performance abnormalities.

[0041] For example, using the secondary metering winding voltage as a reference, the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers are calculated to determine whether there is a voltage anomaly. The preset thresholds include a fourth preset threshold and a fifth preset threshold.

[0042] Specifically, the zero-sequence metering voltage is determined based on the vector sum of the voltages of the secondary metering windings (A, B, and C) of the same group of capacitive voltage transformers. The calculation formula is as follows: .

[0043] Using the secondary metering winding voltages of each of the three-phase capacitive voltage transformers (A, B, and C) as references, calculate the differences between the secondary protection winding voltage and the secondary measurement winding voltage and their corresponding references, as well as the difference between the zero-sequence metering voltage and the secondary zero-sequence voltage winding voltage. For example, for phase A, calculate the changes in the other two windings for phase A as follows:

[0044] ; Similarly, the differences between the secondary protection winding voltage and the secondary measurement winding voltage of phases B and C and the corresponding reference can be calculated, as well as the difference between the zero-sequence metering voltage and the secondary zero-sequence voltage winding voltage.

[0045] For any phase, if the difference between the secondary protection winding voltage or the secondary measurement winding voltage and the reference voltage exceeds the fourth preset threshold, or the zero-sequence metering voltage exceeds the fifth preset threshold, then the voltage of the capacitive voltage transformer in that phase is determined to be abnormal. The range of the fourth preset threshold is […]. The range of the fifth preset threshold is [0.12V, +0.12V]. 0.05V, +0.05V).

[0046] Capacitive voltage transformers exhibiting both current and voltage anomalies are classified as having insulation performance abnormalities and are subject to on-site testing for verification.

[0047] As described above, this invention achieves early warning of insulation faults by determining the power balance within the target substation (power generation equals the sum of power consumption and power output). It can detect system-level anomalies without relying on power outage tests, significantly improving power supply reliability and avoiding the decline in grid stability caused by frequent power outages.

[0048] Furthermore, by using the primary-to-ground current of the same group of capacitive voltage transformers within the target substation, the current anomaly of a group of capacitive voltage transformers can be determined, and the group of capacitive voltage transformers with the current anomaly can be accurately located.

[0049] Furthermore, using the secondary metering winding voltage as a benchmark, the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers are compared to eliminate interference from non-core faults such as loose secondary circuit wiring, thus pinpointing the fault to a single capacitive voltage transformer.

[0050] This invention forms a logical closed loop through the above three criteria, and realizes online identification of insulation performance based on electrical energy and capacitive voltage transformer operation data. It does not require power outages, avoids blind testing of all capacitive voltage transformers in the station, and uses high-precision secondary metering winding voltage as a benchmark to sensitively identify insulation degradation. It is applicable to equipment of the same batch and different batches, improving identification accuracy and power supply reliability.

[0051] like Figure 2 As shown, Figure 2 This is a flowchart illustrating another embodiment of the method for identifying the insulation performance of a capacitive voltage transformer based on metering data provided by the present invention. The method includes: S201: Obtain the internal energy data of the target substation, as well as the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary to ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measuring winding voltage and secondary zero-sequence voltage winding voltage.

[0052] For example, the electrical energy information of the line or bus where the capacitive voltage transformer is located can be obtained through an electrical energy data platform, including the generator output, power consumption, and power output.

[0053] The substation operation support system acquires the ground current data of the primary side of all capacitive voltage transformers within the substation, denoted as i. a1 i b1 i c1 i a2 i b2 i c2 、、·····、, respectively correspond to the A, B, and C phases of different lines or busbars.

[0054] The secondary metering winding voltage u of the phase A capacitive voltage transformer is obtained through the real-time monitoring system. jl-a1 Secondary protection winding voltage u bh-a1 Secondary measurement of winding voltage u cl-a1 and the secondary zero-sequence voltage winding voltage u lx-a1 Similarly, obtain the data for phase B and phase C.

[0055] In this embodiment, daily comprehensive electricity consumption, plant power consumption, and power loss (i.e., consumed power) data from June 20th to September 16th were obtained from the power energy platform of a certain power plant (e.g., Figure 3 As shown, Figure 3 This table shows the daily comprehensive electricity consumption, plant power consumption, and power loss data for a certain power station from June 20th to September 16th. Simultaneously, the primary-to-ground current and secondary voltage data (including secondary metering winding voltage, secondary protection winding voltage, secondary measuring winding voltage, and secondary zero-sequence voltage winding voltage) of each capacitive voltage transformer in circuit I, circuit II, bus I, and bus II were measured through the substation operation support system, as shown in Table 1.

[0056] Table 1 Secondary voltage data

[0057] S202: If the power generation is not equal to the sum of the power consumption and the power output, then the target substation is determined to have an abnormal power balance.

[0058] For example, combined Figure 3 According to the daily electricity consumption calculation data of a certain power plant, the daily comprehensive electricity consumption = generator output - transmitted output, and the daily power loss = daily comprehensive electricity consumption - daily plant power consumption. From June 20th to July 17th, the power plant operators found that the daily comprehensive electricity consumption of the power plant had decreased, from 88.6133 MWh to 55.1965 MWh and continued to decline significantly. By August 28th, the daily comprehensive electricity consumption had decreased to 16.6981 MWh. At the same time, the daily power loss decreased day by day until it became negative and showed an increasing trend. This clearly did not meet the balance relationship, and the line loss rate was abnormal. Therefore, it was determined that the next step was required.

[0059] S203: When there is an abnormal power balance in the target substation, the current anomaly is judged based on the primary ground current of the same group of capacitive voltage transformers in the target substation, and several groups of capacitive voltage transformers with abnormal current are obtained. A group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus.

[0060] For example, the primary-to-ground current data of the capacitive voltage transformer obtained through the substation operation support system is subjected to one of the following two consistency judgment methods (either one or a combination may be used): Method 1: Calculate the vector sum of the primary-to-ground currents of the three-phase capacitive voltage transformers (A, B, and C) in the same group. If the capacitive voltage transformers in the same group are from the same batch and model, determine whether the absolute value of the vector sum exceeds a first preset threshold. If so, it is determined to be an abnormal current. If the capacitive voltage transformers in the same group are not from the same batch and model, and the vector sum is a first fixed value under normal operating conditions, determine whether the vector sum is within the preset first fixed value range. Otherwise, it is determined to be an abnormal current.

[0061] Method 2: Calculate the absolute value or ratio of the difference between the primary-to-ground current of phase A capacitive voltage transformer and the primary-to-ground current of phase B capacitive voltage transformer, as the first variable; calculate the absolute value or ratio of the difference between the primary-to-ground current of phase A capacitive voltage transformer and the primary-to-ground current of phase C capacitive voltage transformer, as the second variable; calculate the absolute value or ratio of the difference between the primary-to-ground current of phase B capacitive voltage transformer and the primary-to-ground current of phase C capacitive voltage transformer, as the third variable; form time series from the first, second, and third variables respectively; calculate the difference between the value at the next moment and the value at the previous moment in each time series, and determine whether the difference exceeds a second preset threshold. If so, it is determined to be an abnormal current.

[0062] In this embodiment, actual measurements revealed a significant inconsistency between the ground currents of the capacitive voltage transformers in each phase of the I circuit, prompting a move to the next step.

[0063] S204: Determine the zero-sequence metering voltage based on the vector sum of the secondary metering winding voltages of the A, B, and C phase capacitive voltage transformers in the same group.

[0064] For example, the zero-sequence metering voltage is determined based on the vector sum of the voltages of the A, B, and C phase secondary metering windings of the same group of capacitive voltage transformers. The calculation formula is as follows: .

[0065] S205: Based on the zero-sequence metering voltage, perform voltage anomaly judgment for a group of capacitive voltage transformers.

[0066] For example, it is determined whether the absolute value of the zero-sequence metering voltage exceeds a third preset threshold; if it does, the voltage is determined to be abnormal. The third preset threshold is 0.05V.

[0067] S206: Using the secondary metering winding voltages of the three-phase capacitive voltage transformers A, B, and C as references, calculate the differences between the secondary protection winding voltage and the secondary measurement winding voltage and the corresponding references.

[0068] S207: For any phase, determine whether the difference between the secondary protection winding voltage and the secondary measurement winding voltage of the current phase and the corresponding reference exceeds the fourth preset threshold, and whether the secondary zero-sequence voltage winding voltage exceeds the fifth preset threshold. If so, the current phase voltage is judged to be abnormal.

[0069] For example, using the secondary metering winding voltages of each of the three-phase capacitive voltage transformers A, B, and C as a reference, the differences between the secondary protection winding voltage and the secondary measurement winding voltage and the corresponding reference are calculated respectively. For any phase, it is determined whether the difference between the current phase's secondary protection winding voltage and the secondary measurement winding voltage and the corresponding reference exceeds a fourth preset threshold, and whether the secondary zero-sequence voltage winding voltage exceeds a fifth preset threshold. If so, the current phase voltage is determined to be abnormal. Capacitive voltage transformers that simultaneously exhibit current and voltage abnormalities are considered capacitive voltage transformers with abnormal insulation performance. The preset thresholds include the fourth preset threshold and the fifth preset threshold.

[0070] The difference between the voltage of the secondary protection winding and the voltage of the secondary metering winding, as well as the difference between the voltage of the secondary measuring winding and the voltage of the secondary metering winding, can be calculated for auxiliary judgment, as shown in the following formula:

[0071] If the difference between any phases exceeds the fourth preset threshold, the insulation performance of the capacitive voltage transformer in that phase is determined to be abnormal.

[0072] Furthermore, if the zero-sequence metering voltage exceeds the set fifth preset threshold, it is also judged as abnormal.

[0073] Specifically, taking phase B of line I as an example: The zero-sequence metering voltage is determined by the vector sum of the voltages of the secondary metering windings of phases A, B, and C of circuit I. The calculation formula is as follows: =171.41V.

[0074] Secondary metering winding voltage U jl b1 =56.60V as the reference value; Secondary measurement of winding voltage U cl b1 =57.50V, the absolute difference ΔU from the reference value cl b1 =∣57.50 56.60 | = 0.90V; Secondary protection winding voltage U bh b1=57.55V, the absolute difference ΔU from the reference value bh b1 =∣57.55 56.60 | = 0.95V; Secondary zero-sequence voltage winding voltage U lx b1 =1.9V.

[0075] The fourth preset threshold was set to 0.12V, and the fifth preset threshold was set to 0.05V. The voltage difference between the secondary measuring winding and the protection winding both exceeded the thresholds (0.90V > 0.12V, 0.95V > 0.12V). Simultaneously, the secondary zero-sequence voltage winding voltage of 1.9V exceeded 0.05V. Furthermore, the voltage to ground at the N-terminus of the secondary winding of all capacitive voltage transformers was close to zero, ruling out ground fault interference. Based on the above data, it was determined that the B-phase capacitive voltage transformer of circuit I had abnormal insulation performance and required further offline testing for verification.

[0076] It should be noted that the data analysis methods for other phases and the II circuit are the same, and will not be repeated here.

[0077] S208: Capacitive voltage transformers that currently exhibit both current and voltage anomalies are classified as capacitive voltage transformers with insulation performance abnormalities.

[0078] S209: Conduct on-site testing and verification of capacitive voltage transformers with abnormal insulation performance under power outage conditions.

[0079] For example, for capacitive voltage transformers determined to be abnormal, a power outage is arranged for offline testing to confirm the issue. Typically, dielectric loss testing and capacitance testing are used to calculate the relative error of the capacitance of each section.

[0080] In this embodiment, a power outage test was conducted on the capacitive voltage transformer of line I, and the following results were obtained: The relative error of the upper section capacity of phase A is -0.01%, and that of the lower section is -0.02% (normal). The relative error of the capacity of the upper section of phase B is +0.22%, and that of the lower section is -0.06% (the upper section is close to exceeding the limit). The relative error of the upper section capacity of phase C is +3.1%, and that of the lower section is +0.48% (the upper section significantly exceeds the standard).

[0081] The results showed that the capacitance of phases B and C of circuit I had changed significantly, and the insulation performance had deteriorated, consistent with the online judgment result in step S208. Thus, the capacitive voltage transformer with insulation abnormalities was successfully identified.

[0082] like Figure 4 As shown, Figure 4 This is a schematic diagram of an embodiment of a capacitive voltage transformer insulation performance identification system based on metering data provided by the present invention. The system 10 includes: The data acquisition module 11 is used to acquire the internal electrical energy data of the target substation and the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage.

[0083] The power balance anomaly judgment module 12 is used to determine that the target substation has a power balance anomaly if the power generation is not equal to the sum of the power consumption and the power transmission.

[0084] The current anomaly judgment module 13 is used to judge the current anomaly based on the primary ground current of the same group of capacitive voltage transformers in the target substation when there is an abnormal power balance in the target substation. It obtains several groups of capacitive voltage transformers with current anomalies. A group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus.

[0085] The insulation performance abnormality identification module 14 is used to determine the voltage deviation of the secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers based on the secondary metering winding voltage. If any voltage deviation exceeds the first preset threshold, it is determined to be a voltage abnormality. Capacitive voltage transformers that have both current abnormality and voltage abnormality are regarded as capacitive voltage transformers with insulation performance abnormality.

[0086] For example, in the data acquisition module 11, the station's internal energy data and the operating data of each capacitive voltage transformer in the target substation are acquired. The station's internal energy data includes power generation, power consumption and power transmission. The operating data includes primary to ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage.

[0087] In the power balance anomaly judgment module 12, power balance judgment is performed based on the collected power generation, power consumption, and power transmission: if the power generation is not equal to the sum of the power consumption and the power transmission, it is determined that there is a power balance anomaly in the target substation and the current anomaly judgment is initiated.

[0088] In the current anomaly judgment module 13, the primary-to-ground current data of the capacitive voltage transformer acquired by the substation operation support system is subjected to one of the following two consistency judgment methods (one can be selected or a combination of them): Method 1: Calculate the vector sum of the primary-to-ground currents of the three-phase capacitive voltage transformers (A, B, and C) in the same group. If the capacitive voltage transformers in the same group are from the same batch and model, determine whether the absolute value of the vector sum exceeds a first preset threshold. If so, it is determined to be an abnormal current. If the capacitive voltage transformers in the same group are not from the same batch and model, and the vector value is a first fixed value under normal operating conditions, determine whether the vector sum is within the preset first fixed value range. Otherwise, it is determined to be an abnormal current.

[0089] Method 2: Calculate the absolute value or ratio of the difference between the primary-to-ground current of phase A capacitive voltage transformer and the primary-to-ground current of phase B capacitive voltage transformer, as the first variable; calculate the absolute value or ratio of the difference between the primary-to-ground current of phase A capacitive voltage transformer and the primary-to-ground current of phase C capacitive voltage transformer, as the second variable; calculate the absolute value or ratio of the difference between the primary-to-ground current of phase B capacitive voltage transformer and the primary-to-ground current of phase C capacitive voltage transformer, as the third variable; form time series from the first, second, and third variables respectively; calculate the difference between the value at the next moment and the value at the previous moment in each time series, and determine whether the difference exceeds the corresponding second preset threshold. If so, it is judged as an abnormal current.

[0090] In the insulation performance anomaly identification module 14, the secondary metering winding voltages of the three-phase capacitive voltage transformers A, B, and C are used as references to calculate the differences between the secondary protection winding voltage and the secondary measurement winding voltage and the corresponding references. For any phase, it is determined whether the difference between the secondary protection winding voltage and the secondary measurement winding voltage of the current phase and the corresponding reference exceeds the fourth preset threshold, and whether the secondary zero-sequence voltage winding voltage exceeds the fifth preset threshold. If so, it is determined that the voltage of the current phase is abnormal. The capacitive voltage transformers that have both current and voltage anomalies in the current phase are identified as capacitive voltage transformers with insulation performance anomalies.

[0091] like Figure 5 As shown, Figure 5 This is a schematic diagram of an embodiment of the device provided by the present invention. The device 20 includes a memory 21 and a processor 22. The memory 21 stores a computer program, and the processor 22 executes the computer program during operation to achieve, for example... Figure 1 and Figure 2 The method shown.

[0092] The specific technical details of the multimodal power transmission corridor hidden danger target identification method implemented by the above-mentioned device 20 when executing the computer program have been discussed in detail in the above method steps, so they will not be repeated here.

[0093] like Figure 6 As shown, Figure 6 This is a schematic diagram of the structure of an embodiment of the medium provided by the present invention. The medium 30 stores at least one computer program 31, which is executed by the processor 22 to perform the following... Figure 1 and Figure 2 The method shown is detailed above and will not be repeated here. In one embodiment, the medium 30 can be a storage chip, hard disk, portable hard disk, USB flash drive, optical disk, or other read / write storage device, or even a server, etc.

[0094] Furthermore, the processes depicted in the accompanying drawings do not necessarily have to be performed in the specific or sequential order shown to achieve the desired result. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0095] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of apparatus, devices, and non-volatile computer-readable storage media are basically similar to the method embodiments, and therefore described more simply; relevant parts can be referred to the descriptions of the method embodiments.

[0096] The apparatus, device, non-volatile computer-readable storage medium and method provided in the embodiments of this specification are corresponding. Therefore, the apparatus, device and non-volatile computer storage medium also have similar beneficial technical effects as the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding apparatus, device and non-volatile computer storage medium will not be repeated here.

[0097] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0098] For ease of description, the above apparatus is described by dividing it into various functional units. Of course, in implementing this specification, the functions of each unit can be implemented in one or more software and / or hardware components. Those skilled in the art will understand that the embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, the embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0099] This specification is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0100] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0102] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0103] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0104] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0105] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0106] This specification can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This specification can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0107] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0108] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for identifying the insulation performance of a capacitive voltage transformer based on metering data, characterized in that, The method includes: Acquire the internal electrical energy data of the target substation, as well as the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measuring winding voltage and secondary zero-sequence voltage winding voltage. If the power generation is not equal to the sum of the power consumption and the power output, then the target substation is determined to have an abnormal power balance. When there is an abnormal power balance in the target substation, the current anomaly is judged based on the primary ground current of the same group of capacitive voltage transformers in the target substation, and several groups of capacitive voltage transformers with abnormal current are obtained. The group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus. Using the secondary metering winding voltage as a reference, the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers are determined. If any voltage deviation exceeds a preset threshold, it is determined to be a voltage abnormality. Capacitive voltage transformers that simultaneously exhibit current and voltage abnormalities are considered to have abnormal insulation performance.

2. The method for identifying the insulation performance of a capacitive voltage transformer based on metering data according to claim 1, characterized in that, The current anomaly detection based on the primary-to-ground current of the same group of capacitive voltage transformers within the target substation specifically includes: Calculate the vector sum of the primary-to-ground currents of the three-phase capacitive voltage transformers A, B, and C in the same group of capacitive voltage transformers; If the capacitive voltage transformers in the same group are from the same batch, then determine whether the absolute value of the vector sum exceeds the first preset threshold; if so, then determine that the current is abnormal. If the capacitive voltage transformers in the same group are not from the same batch or model, and the vector sum is a first fixed value under normal operating conditions, then it is determined whether the vector sum is within the preset first fixed value range; otherwise, it is determined to be an abnormal current.

3. The method of claim 1, wherein the method further comprises: When an abnormal power balance exists at the target substation, the current anomaly judgment is performed based on the primary-to-ground current of the same group of capacitive voltage transformers within the target substation, specifically including: Calculate the absolute value or ratio of the difference between the primary current to ground of phase A capacitive voltage transformer and the primary current to ground of phase B capacitive voltage transformer, and use this as the first variable. Calculate the absolute value or ratio of the difference between the primary current to ground of phase A capacitive voltage transformer and the primary current to ground of phase C capacitive voltage transformer, and use it as the second variable. Calculate the absolute value or ratio of the difference between the primary current to ground of phase B capacitive voltage transformer and the primary current to ground of phase C capacitive voltage transformer, and use it as the third variable. The first change, the second change, and the third change are respectively formed into time series; Calculate the difference between the value of the next time step and the value of the previous time step in each time series, and determine whether the difference exceeds a second preset threshold. If so, it is determined to be an abnormal current.

4. The method of claim 1, wherein the method is based on the metering data of the capacitor voltage transformer. The step of comparing the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers with the secondary metering winding voltage as a reference, and determining that any voltage deviation exceeds a first preset threshold as an abnormal voltage and identifying the capacitive voltage transformer with abnormal insulation performance, further includes: The zero-sequence metering voltage is determined by the vector sum of the secondary metering winding voltages of the A, B, and C phase capacitive voltage transformers in the same group. Based on the zero-sequence metering voltage, a voltage anomaly is determined for a group of capacitive voltage transformers.

5. The method of claim 4, wherein the method further comprises: The step of determining voltage anomalies in a set of capacitive voltage transformers based on the zero-sequence metered voltage specifically includes: Determine whether the absolute value of the zero-sequence metering voltage exceeds the third preset threshold. If it does, the voltage is determined to be abnormal.

6. The method for identifying the insulation performance of a capacitive voltage transformer based on metering data according to claim 4, characterized in that, The preset thresholds include a fourth preset threshold and a fifth preset threshold. The step of determining the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers, based on the secondary metering winding voltage, is defined as follows: If any voltage deviation exceeds the preset threshold, it is determined to be a voltage anomaly. Capacitive voltage transformers exhibiting both current and voltage anomalies are considered capacitive voltage transformers with insulation performance abnormalities. Specifically, this includes: Using the secondary metering winding voltages of the three-phase capacitive voltage transformers A, B, and C as references, calculate the differences between the secondary protection winding voltage and the secondary measurement winding voltage and the corresponding references. For any phase, determine whether the difference between the voltage of the secondary protection winding and the voltage of the secondary measurement winding of the current phase and the corresponding reference exceeds the fourth preset threshold, and whether the voltage of the secondary zero-sequence voltage winding exceeds the fifth preset threshold. If so, it is determined that the voltage of the current phase is abnormal. Capacitive voltage transformers that currently exhibit both current and voltage anomalies are considered to have insulation performance defects.

7. The method for identifying the insulation performance of a capacitive voltage transformer based on metering data according to claim 1, characterized in that, The step of determining the voltage deviations of the secondary protection winding voltage, secondary measurement winding voltage, and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers, based on the secondary metering winding voltage, and determining that any voltage deviation exceeds a preset threshold, is an abnormal voltage condition. After classifying capacitive voltage transformers exhibiting both current and voltage abnormalities as having insulation performance abnormalities, the method further includes: The capacitive voltage transformer with abnormal insulation performance was tested and verified in the field under power outage conditions.

8. A system for identifying the insulation performance of a capacitive voltage transformer based on metrological data, characterized by The system includes: The data acquisition module is used to acquire the internal electrical energy data of the target substation and the operating data of each capacitive voltage transformer in the target substation. The internal energy data includes power generation, power consumption and power transmission. The operating data includes primary ground current, secondary metering winding voltage, secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage. The power balance anomaly detection module is used to determine that the target substation has a power balance anomaly if the power generation is not equal to the sum of the power consumption and the power transmission. The current anomaly judgment module is used to judge the current anomaly based on the primary ground current of the same group of capacitive voltage transformers in the target substation when there is an abnormal power balance in the target substation. It obtains several groups of capacitive voltage transformers with current anomalies. The group of capacitive voltage transformers includes the A-phase capacitive voltage transformer, B-phase capacitive voltage transformer and C-phase capacitive voltage transformer on the current line or bus. The insulation performance abnormality identification module is used to determine the voltage deviation of the secondary protection winding voltage, secondary measurement winding voltage and secondary zero-sequence voltage winding voltage of the same group of capacitive voltage transformers based on the secondary metering winding voltage. If any voltage deviation exceeds a first preset threshold, it is determined to be a voltage abnormality. Capacitive voltage transformers that have both current abnormality and voltage abnormality are regarded as capacitive voltage transformers with insulation performance abnormalities.

9. A computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method as claimed in any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method as claimed in any one of claims 1 to 7.

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