阅读说明：本技术 一种高压开关pt柜过电压智能识别方法、装置及系统 (Intelligent overvoltage identification method, device and system for high-voltage switch PT cabinet ) 是由 许谱名 李欣 赵世华 叶会生 刘赟 谢耀恒 何智强 黄海波 袁培 闫迎 于 2021-08-10 设计创作，主要内容包括：本发明公开了一种高压开关PT柜过电压智能识别方法、装置及系统,本发明方法包括在零序电流I大于电流整定值I0或零序电压U大于电压整定值U0的前提下,若低频分量实测值UL大于低频分量整定值U0L,则判定过电压类型为分频铁磁谐振过电压；若高频分量实测值UH大于高频分量整定值U0H,则判定过电压类型为高频铁磁谐振过电压；否则若满足条件R1～R4中任意一项,则判定过电压类型为基波铁磁谐振过电压,否则判定过电压类型为非铁磁谐振过电压。本发明能够提高高压PT柜的过电压智能采集及研判识别能力,解决高压PT柜过电压故障频发、过电压识别困难、过电压抑制困难的问题,可以准确、快速的监测并识别系统过电压。(The invention discloses an intelligent identification method, a device and a system for overvoltage of a high-voltage switch PT cabinet, wherein the method comprises the steps of judging the overvoltage type to be frequency division ferromagnetic resonance overvoltage if a low-frequency component measured value UL is greater than a low-frequency component setting value U0L on the premise that a zero-sequence current I is greater than a current setting value I0 or a zero-sequence voltage U is greater than a voltage setting value U0; if the measured high-frequency component UH is larger than the high-frequency component setting value U0H, judging the overvoltage type to be a high-frequency ferromagnetic resonance overvoltage; otherwise, if any one of the conditions R1-R4 is met, the overvoltage type is judged to be a fundamental wave ferromagnetic resonance overvoltage, and if not, the overvoltage type is judged to be a non-ferromagnetic resonance overvoltage. The invention can improve the intelligent overvoltage acquisition, study and judgment recognition capability of the high-voltage PT cabinet, solves the problems of frequent overvoltage faults, difficult overvoltage recognition and difficult overvoltage suppression of the high-voltage PT cabinet, and can accurately and quickly monitor and recognize the system overvoltage.)

1. An intelligent overvoltage identification method for a high-voltage switch PT cabinet is characterized by comprising the following steps:

1) detecting a zero-sequence current I and a zero-sequence voltage U;

2) judging whether the zero-sequence current I is larger than a preset current setting value I0 or the zero-sequence voltage U is larger than a preset voltage setting value U0, if not, ending and exiting; otherwise, executing the next step;

3) carrying out FFT decomposition on the zero sequence voltage U, and extracting a low-frequency component measured value UL and a high-frequency component measured value UH;

4) if the measured value UL of the low-frequency component is greater than a preset low-frequency component setting value U0L, determining that the overvoltage type is a frequency division ferromagnetic resonance overvoltage; if the measured high-frequency component UH is larger than a preset high-frequency component setting value U0H, judging that the overvoltage type is a high-frequency ferromagnetic resonance overvoltage; otherwise, executing the next step;

5) obtaining the amplitude and phase parameters of three-phase voltage; if any one of the conditions R1-R4 is met, the overvoltage type is judged to be a fundamental wave ferromagnetic resonance overvoltage, and if not, the overvoltage type is judged to be a non-ferromagnetic resonance overvoltage; condition R1: the three-phase voltage is increased; condition R2: one phase voltage is reduced, and the other two phase voltages are increased and exceed the line voltage; condition R3: one phase voltage is reduced but not equal to 0 and is in phase reversal with the zero sequence voltage, and the other two phase voltages are increased and equal; condition R4: one phase voltage rises but is not equal to the specified preset multiple of the rated voltage, and the phase voltage is in phase with the zero sequence voltage, and the other two phases are reduced and equal.

2. The intelligent overvoltage identification method for the high-voltage switch PT cabinet according to claim 1, characterized in that after the overvoltage type is determined to be the non-ferromagnetic resonance overvoltage in step 5), the method further comprises the step of determining a criterion L1, and if the criterion L1 is satisfied, the overvoltage type is determined to be a metallic grounding overvoltage; wherein the criterion L1 is: the ratio of the minimum amplitude to the maximum amplitude of the whole period in the three-phase voltage and the absolute error between 0 are smaller than a preset first error setting value.

3. The intelligent identification method for the overvoltage of the high-voltage switch PT cabinet according to claim 2, characterized in that in the judgment of the criterion L1, if the criterion L1 is not established, the judgment of the criterion L2 is further included, and if the criterion L2 is established, the overvoltage type is determined to be an arc grounding overvoltage; the criterion L2 is that the ratio of the minimum amplitude to the maximum amplitude of the whole period exists in the three-phase voltage, the absolute error between 0 is smaller than a preset second error setting value, the second error setting value is larger than the first error setting value, the absolute error between the amplitudes of the other two phases of the voltage is smaller than the first error setting value, and the absolute error between adjacent measuring points exists in the whole period and is larger than a third error setting value.

4. The intelligent identification method for the overvoltage of the high-voltage switch PT cabinet according to claim 3, characterized in that during the judgment of the criterion L2, if the criterion L2 is not established, the judgment of the criterion L3 is further included, and if the criterion L3 is established, the overvoltage type is judged to be the overvoltage of a closing capacitor; wherein the criterion L3 is: and in the whole period, the absolute error between adjacent measuring points is greater than a third error setting value, the absolute error between adjacent measuring points in other parts is less than the first error setting value, and the third error setting value is greater than the second error setting value.

5. The intelligent overvoltage identification method for the high-voltage switch PT cabinet according to claim 4, characterized in that during the judgment of the criterion L3, if the criterion L3 is not established, the judgment of the criterion L4 is further included, and if the criterion L4 is established, the overvoltage type is judged to be lightning overvoltage; wherein the criterion L4 is: and in the whole period, the absolute error between adjacent measuring points is greater than a fourth error setting value, the absolute error between adjacent measuring points in other parts is less than the first error setting value, and the fourth error setting value is greater than the third error setting value.

6. The intelligent identification method for the overvoltage of the high-voltage switch PT cabinet according to claim 5, characterized in that during the judgment of the criterion L4, if the criterion L4 is not established, the judgment of the criterion L5 is further included, and if the criterion L5 is established, the overvoltage type is determined to be a closing no-load line overvoltage; wherein the criterion L5 is: and in the whole period, the absolute error between adjacent measuring points is greater than a fifth error setting value and occurs in a plurality of measuring points, and the fifth error setting value is greater than the first error setting value and is less than the second error setting value.

7. An intelligent identification device for overvoltage of high-voltage switch PT cabinet, comprising a microprocessor and a memory which are connected with each other, characterized in that the microprocessor is programmed or configured to execute the steps of the intelligent identification method for overvoltage of high-voltage switch PT cabinet according to any one of claims 1-6.

8. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program programmed or configured to execute the intelligent overvoltage identification method for a high-voltage switch PT cabinet according to any one of claims 1 to 6.

9. An intelligent identification system for the overvoltage of a high-voltage switch PT cabinet, which is applied with the intelligent identification method for the overvoltage of the high-voltage switch PT cabinet as claimed in any one of claims 1 to 6, and is characterized by comprising a broadband sensing support insulator (1), a PT full-frequency zero-sequence current monitoring unit (2), a PT full-frequency zero-sequence current edge processing unit (3), a full-wave voltage conversion unit (4), a real-time voltage monitoring module (5), a data remote sensing module (6) and an overvoltage identification device (7), wherein the broadband sensing support insulator (1) is arranged in the detected high-voltage switch PT cabinet, the output end of the broadband sensing support insulator (1) is connected with the data remote sensing module (6) through the full-wave voltage conversion unit (4) and the real-time voltage monitoring module (5) in sequence, and the full-frequency zero-sequence current monitoring unit (2) is used for detecting the PT full-frequency zero-sequence current in the detected high-voltage switch PT cabinet, the output end of the PT full-frequency zero-sequence current monitoring unit (2) is connected with the data remote transmission module (6) through the PT full-frequency zero-sequence current edge processing unit (3), and the output end of the data remote transmission module (6) is connected with the overvoltage recognition device (7) through a network.

10. The intelligent overvoltage identification system for the high-voltage switch PT cabinet according to claim 9, characterized in that the overvoltage identification device (7) is further connected with a man-machine module (71), an Internet of things module (72) and a power supply module (73).

Technical Field

The invention relates to the field of intelligent operation and detection of power systems, in particular to an intelligent overvoltage identification method, device and system for a high-voltage switch (PT) cabinet, which are suitable for automatically monitoring, identifying and alarming the operation overvoltage of a transformer substation high-voltage PT cabinet.

Background

With the rapid development of national economy, the grid frame scale of the power grid in China is continuously enlarged, and the number of transformer substations is increased day by day. In a power grid system, a high-voltage switch cabinet is a key device for realizing the connection of a low-voltage side of a transformer substation and a power distribution network, and the safe and stable operation of the high-voltage switch cabinet is directly related to the reliable supply of power consumption of users. The high-voltage switch PT cabinet can collect bus voltage signals and is used for monitoring the running condition of the low-voltage side of a transformer substation, identifying faults in a station or a line and starting trip protection and other functional requirements.

The distribution network system is easily influenced by external overvoltage in the operation process, common overvoltage types comprise metallic grounding overvoltage, fundamental wave ferromagnetic resonance overvoltage, high-frequency ferromagnetic resonance overvoltage, frequency division ferromagnetic resonance overvoltage, arc grounding overvoltage, closing capacitor overvoltage, thunder overvoltage, closing no-load line overvoltage and the like, and serious adverse effects are brought to the safety of equipment and the stable operation of the system. At present, a fault recording system is not generally installed on a low-voltage side of a power grid system, and effective overvoltage real-time monitoring and identification means are not provided, so that the difficulty of overvoltage suppression on the low-voltage side of a transformer substation is greatly increased, and due to the fact that an adopted resonance eliminator is poor in overvoltage type identification capability and insufficient in sampling precision, the actual resonance elimination effect is not ideal, the reason is difficult to find out after a fault occurs, and the targeted prevention and improvement are difficult to carry out. Once overvoltage faults occur on the low-voltage side of a transformer substation or on a distribution line of a corresponding voltage class, the overvoltage faults are often checked through a large amount of later manual intervention, the response speed is low, the power failure time is long, and an efficient, rapid and accurate comprehensive judgment and analysis method is lacked. With the continuous popularization and promotion of the intelligent transformer substation, the overvoltage identification method is slow in research progress in the aspects of intelligent sensing and autonomous analysis and study and judgment functions, limits the intelligent level and the internet of things linkage analysis and diagnosis level of the intelligent transformer substation, and is not beneficial to the realization of the intelligent power grid construction target of the state network company. In summary, in order to improve the overvoltage suppression capability of the high voltage switch PT cabinet, it is necessary to research an apparatus and a method for intelligently identifying the overvoltage of the high voltage switch PT cabinet.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problems in the prior art and the problem of poor overvoltage identification capability of a high-voltage switch PT cabinet, the invention provides an intelligent overvoltage identification method, device and system of the high-voltage switch PT cabinet.

In order to solve the technical problems, the invention adopts the technical scheme that:

an intelligent overvoltage identification method for a high-voltage switch PT cabinet comprises the following steps:

1) detecting a zero-sequence current I and a zero-sequence voltage U;

2) judging whether the zero-sequence current I is larger than a preset current setting value I0 or the zero-sequence voltage U is larger than a preset voltage setting value U0, if not, ending and exiting; otherwise, executing the next step;

3) carrying out FFT decomposition on the zero sequence voltage U, and extracting a low-frequency component measured value UL and a high-frequency component measured value UH;

4) if the measured value UL of the low-frequency component is greater than a preset low-frequency component setting value U0L, determining that the overvoltage type is a frequency division ferromagnetic resonance overvoltage; if the measured high-frequency component UH is larger than a preset high-frequency component setting value U0H, judging that the overvoltage type is a high-frequency ferromagnetic resonance overvoltage; otherwise, executing the next step;

5) obtaining the amplitude and phase parameters of three-phase voltage; if any one of the conditions R1-R4 is met, the overvoltage type is judged to be a fundamental wave ferromagnetic resonance overvoltage, and if not, the overvoltage type is judged to be a non-ferromagnetic resonance overvoltage; condition R1: the three-phase voltage is increased; condition R2: one phase voltage is reduced, and the other two phase voltages are increased and exceed the line voltage; condition R3: one phase voltage is reduced but not equal to 0 and is in phase reversal with the zero sequence voltage, and the other two phase voltages are increased and equal; condition R4: one phase voltage rises but is not equal to the specified preset multiple of the rated voltage, and the phase voltage is in phase with the zero sequence voltage, and the other two phases are reduced and equal.

Optionally, after the overvoltage type is determined to be the non-ferromagnetic resonance overvoltage in step 5), the judgment of a criterion L1 is further included, and if the criterion L1 is satisfied, the overvoltage type is determined to be a metallic grounding overvoltage; wherein the criterion L1 is: the ratio of the minimum amplitude to the maximum amplitude of the whole period in the three-phase voltage and the absolute error between 0 are smaller than a preset first error setting value.

Optionally, when the criterion L1 is judged, if the criterion L1 is not satisfied, the judgment of the criterion L2 is further included, and if the criterion L2 is satisfied, the overvoltage type is determined to be an arc grounding overvoltage; the criterion L2 is that the ratio of the minimum amplitude to the maximum amplitude of the whole period exists in the three-phase voltage, the absolute error between 0 is smaller than a preset second error setting value, the second error setting value is larger than the first error setting value, the absolute error between the amplitudes of the other two phases of the voltage is smaller than the first error setting value, and the absolute error between adjacent measuring points exists in the whole period and is larger than a third error setting value.

Optionally, during the judgment of the criterion L2, if the criterion L2 is not satisfied, the judgment of the criterion L3 is further included, and if the criterion L3 is satisfied, the overvoltage type is determined to be a closing capacitor overvoltage; wherein the criterion L3 is: and in the whole period, the absolute error between adjacent measuring points is greater than a third error setting value, the absolute error between adjacent measuring points in other parts is less than the first error setting value, and the third error setting value is greater than the second error setting value.

Optionally, during the judgment of the criterion L3, if the criterion L3 is not satisfied, the judgment of the criterion L4 is further included, and if the criterion L4 is satisfied, the overvoltage type is determined to be the lightning overvoltage; wherein the criterion L4 is: and in the whole period, the absolute error between adjacent measuring points is greater than a fourth error setting value, the absolute error between adjacent measuring points in other parts is less than the first error setting value, and the fourth error setting value is greater than the third error setting value.

Optionally, during the judgment of the criterion L4, if the criterion L4 is not satisfied, the judgment of the criterion L5 is further included, and if the criterion L5 is satisfied, the overvoltage type is determined to be a closing no-load line overvoltage; wherein the criterion L5 is: and in the whole period, the absolute error between adjacent measuring points is greater than a fifth error setting value and occurs in a plurality of measuring points, and the fifth error setting value is greater than the first error setting value and is less than the second error setting value.

In addition, the invention also provides an intelligent overvoltage identification device for the high-voltage switch PT cabinet, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the steps of the intelligent overvoltage identification method for the high-voltage switch PT cabinet.

In addition, the invention also provides a computer readable storage medium, wherein a computer program programmed or configured to execute the intelligent overvoltage identification method for the high-voltage switch PT cabinet is stored in the computer readable storage medium.

In addition, the invention also provides an intelligent identification system for the overvoltage of the high-voltage switch PT cabinet, which is used for applying the intelligent identification method for the overvoltage of the high-voltage switch PT cabinet, and comprises a broadband sensing support insulator, a PT full-frequency zero-sequence current monitoring unit, a PT full-frequency zero-sequence current edge processing unit, a full-wave voltage conversion unit, a real-time voltage monitoring module, a data remote transmission module and an overvoltage identification device, wherein the broadband sensing support insulator is arranged in the detected high-voltage switch PT cabinet, the output end of the broadband sensing support insulator is connected with the data remote transmission module through the full-wave voltage conversion unit and the real-time voltage monitoring module in sequence, the PT full-frequency zero-sequence current monitoring unit is used for detecting the PT full-frequency zero-sequence current in the detected high-voltage switch PT cabinet, the output end of the PT full-frequency zero-sequence current monitoring unit is connected with the data remote transmission module through the PT full-frequency zero-sequence current edge processing unit, and the output end of the data remote transmission module is connected with the overvoltage identification device through a network.

Optionally, the overvoltage identification device is further connected with a man-machine module, an internet of things module and a power module.

Compared with the prior art, the invention has the following technical effects: on the premise that the zero-sequence current I is greater than the current setting value I0 or the zero-sequence voltage U is greater than the voltage setting value U0, if the actual measured value UL of the low-frequency component is greater than the setting value U0L of the low-frequency component, the overvoltage type is judged to be frequency division ferromagnetic resonance overvoltage; if the measured high-frequency component UH is larger than the high-frequency component setting value U0H, judging the overvoltage type to be a high-frequency ferromagnetic resonance overvoltage; otherwise, if any one of the conditions R1-R4 is met, the overvoltage type is judged to be fundamental wave ferromagnetic resonance overvoltage, otherwise, the overvoltage type is judged to be non-ferromagnetic resonance overvoltage, so that the identification of frequency division ferromagnetic resonance overvoltage, high frequency ferromagnetic resonance overvoltage, fundamental wave ferromagnetic resonance overvoltage and non-ferromagnetic resonance overvoltage can be realized, the intelligent acquisition and research and judgment identification capability of overvoltage of the high-voltage PT cabinet can be improved, the problems of frequent overvoltage fault occurrence, difficult overvoltage identification and difficult overvoltage suppression of the high-voltage PT cabinet are solved, and the system overvoltage can be accurately and rapidly monitored and identified.

Drawings

FIG. 1 is a schematic diagram of a basic flow of a method according to an embodiment of the present invention.

FIG. 2 is a flow chart of a further classification determination of non-ferroresonant overvoltage in an embodiment of the invention.

Fig. 3 is a schematic structural diagram of an intelligent overvoltage identification system for a high-voltage switch PT cabinet according to an embodiment of the present invention.

Fig. 4 is a typical waveform diagram of a fundamental ferroresonant overvoltage in an embodiment of the invention.

Fig. 5 is a typical waveform diagram of a divided ferromagnetic resonance overvoltage in an embodiment of the invention.

Fig. 6 is a typical waveform diagram of a high frequency ferroresonant overvoltage in an embodiment of the invention.

FIG. 7 is a typical waveform diagram of metallic ground overvoltage in an embodiment of the present invention.

FIG. 8 is a typical waveform diagram of arc grounding overvoltage in the embodiment of the present invention.

Fig. 9 is a typical waveform diagram of the overvoltage of the closing capacitor in the embodiment of the invention.

Fig. 10 is a typical waveform diagram of a lightning overvoltage in the embodiment of the present invention.

Fig. 11 is a typical waveform diagram of the overvoltage of the closing no-load line in the embodiment of the invention.

Detailed Description

As shown in fig. 1, the intelligent identification method for overvoltage of the high-voltage switch PT cabinet in this embodiment includes:

1) detecting a zero-sequence current I and a zero-sequence voltage U;

2) judging whether the zero-sequence current I is larger than a preset current setting value I0 or the zero-sequence voltage U is larger than a preset voltage setting value U0, if not, ending and exiting; otherwise, executing the next step;

3) carrying out FFT decomposition on the zero sequence voltage U, and extracting a low-frequency component measured value UL and a high-frequency component measured value UH;

4) if the measured value UL of the low-frequency component is greater than a preset low-frequency component setting value U0L, determining that the overvoltage type is a frequency division ferromagnetic resonance overvoltage; if the measured high-frequency component UH is larger than a preset high-frequency component setting value U0H, judging that the overvoltage type is a high-frequency ferromagnetic resonance overvoltage; otherwise, executing the next step;

5) obtaining the amplitude and phase parameters of three-phase voltage; if any one of the conditions R1-R4 is met, the overvoltage type is judged to be a fundamental wave ferromagnetic resonance overvoltage, and if not, the overvoltage type is judged to be a non-ferromagnetic resonance overvoltage; condition R1: the three-phase voltage is increased; condition R2: one phase voltage is reduced, and the other two phase voltages are increased and exceed the line voltage; condition R3: one phase voltage is reduced but not equal to 0 and is in phase reversal with the zero sequence voltage, and the other two phase voltages are increased and equal; condition R4: one phase voltage rises but is not equal to the specified preset multiple of the rated voltage, and the phase voltage is in phase with the zero sequence voltage, and the other two phases are reduced and equal.

Ferromagnetic resonance is a nonlinear resonance phenomenon existing in a power system, a large number of capacitors exist in the power system, such as stray capacitors of a bus, break capacitors of a circuit breaker, line distribution capacitors and the like, and the nonlinear resonance formed by the capacitors and nonlinear inductors in a voltage transformer is the essence of ferromagnetic resonance. Generally, the inductance L of the voltage transformer is larger than the capacitance to ground C in the system, but in some cases, such as the moment of single-phase ground fault elimination, the two capacitances to ground which are not short-circuited are discharged through the grounding point of PT, at this time, a large current flows through PT, PT is saturated, and therefore the inductance L is reduced, so that there is a chance to match with the capacitance in the system, and ferromagnetic resonance occurs. The frequency of resonance is not fixed and the resulting stable resonance frequency is typically an integer fraction of a time (1/2; 1/3; 1/5) or an integer number of times (1; 3; 5) to facilitate energy extraction from the nonlinear element to maintain the resonance state. Ferromagnetic resonance can be classified into low-frequency resonance, power-frequency resonance, and high-frequency resonance according to frequency. The low-frequency resonance voltage amplitude is low, but the current is large, so that the harm is large; the high frequency resonance voltage is high in amplitude but small in occurrence probability. Because the existing microcomputer device can easily perform frequency spectrum analysis on zero sequence voltage, frequency domain information is obtained through Fast Fourier Transform (FFT), and if low-frequency/high-frequency components reach a certain threshold value, low-frequency/high-frequency resonance is judged. Therefore, the high-frequency resonance and the frequency division resonance can be identified by analyzing the frequency and the numerical value of the zero sequence voltage, and the identification is relatively easy. The intelligent identification method for the overvoltage of the high-voltage switch PT cabinet can realize identification of frequency division ferromagnetic resonance overvoltage, high-frequency ferromagnetic resonance overvoltage, fundamental wave ferromagnetic resonance overvoltage and non-ferromagnetic resonance overvoltage, can improve intelligent acquisition and study and judgment identification capabilities of the overvoltage of the high-voltage PT cabinet, solves the problems of frequent overvoltage faults, difficult overvoltage identification and difficult overvoltage suppression of the high-voltage PT cabinet, and can accurately and quickly monitor and identify system overvoltage. The typical waveform diagram of the fundamental ferroresonance overvoltage is shown in fig. 4, the fundamental ferroresonance has amplitude difference in a measurement period, and the three-phase voltage conforms to the sine law. The decision logic of the fundamental ferroresonance on the program is as follows:

condition R1: the three-phase voltage is increased;

condition R2: one phase voltage is reduced, and the other two phase voltages are increased and exceed the line voltage;

condition R3: one phase voltage is reduced but not equal to 0 and is in phase reversal with the zero sequence voltage, and the other two phase voltages are increased and equal;

condition R4: one phase voltage is raised but not equal to a specified preset multiple of the rated voltage (which can be set empirically, for example, 1.5 times in this embodiment), and is in phase with the zero sequence voltage, and the other two phases are lowered and equal.

In addition, the fundamental ferroresonant overvoltage can also adopt the following judgment logic: and judging after receiving a three-phase voltage of a complete period, wherein the amplitude of the three-phase voltage is greater than 0, the absolute error between the three-phase voltage and the three-phase voltage is 30-100% (adjustable in a program), the Euclidean distance between the absolute value of the first half period and the absolute value of the second half period of the three-phase voltage is within 5% (adjustable in a program), if the conditions are met, the fundamental wave ferroresonance is judged, and if the conditions are not met, other fault types are judged.

In this embodiment, if the measured low-frequency component UL is greater than the preset low-frequency component setting value U0L, it is determined that the overvoltage type is the frequency division ferromagnetic resonance overvoltage. A typical waveform diagram of the frequency-division ferroresonance overvoltage is shown in fig. 5, and compared with the fundamental ferroresonance and the high-frequency ferroresonance, the frequency-division ferroresonance overvoltage significantly changes the amplitude and waveform shape of the first half period and the second half period, and the amplitude of the three-phase voltage is higher as a whole. In addition, the divided ferroresonant overvoltage may also employ the following decision logic: and (3) judging after the host machine receives a three-phase voltage of a complete measurement period, wherein the amplitude of the three-phase voltage is greater than 0, the absolute error between the three-phase voltage and the absolute value of the first half period is within 10%, the Euclidean distance between the absolute value of the first half period and the absolute value of the second half period of the three-phase voltage is greater than 20% (adjustable in a program), the amplitude of the three-phase voltage is 30% (adjustable in the program) of the maximum value of the normal voltage, if the conditions are met, the frequency division ferromagnetic resonance overvoltage is judged, and otherwise, other fault types are judged.

In this embodiment, if the measured high-frequency component UH is greater than the preset high-frequency component setting value U0H, it is determined that the overvoltage type is a high-frequency ferromagnetic resonance overvoltage. A typical waveform diagram of the high-frequency ferroresonance overvoltage is shown in fig. 6, the high-frequency ferroresonance overvoltage has amplitude difference in a measurement period, the amplitude is higher overall, and the high-frequency ferroresonance overvoltage does not conform to the sine law. In addition, the following decision logic can also be used for the high-frequency ferroresonant overvoltage: after receiving a three-phase voltage of a complete period, judging, wherein the amplitude of the three-phase voltage is greater than 0, the absolute error between the three-phase voltage and the three-phase voltage is 10% -100% (adjustable in a program), the Euclidean distance between the absolute value of the first half period and the absolute value of the second half period of the three-phase voltage is greater than 5% (adjustable in a program), the amplitude of the three-phase voltage is 30% (adjustable in a program) of the maximum value of the normal voltage, if the conditions are met, judging that the three-phase voltage is high-frequency ferromagnetic resonance, otherwise, judging that the three-phase voltage is of other fault types.

Because the zero sequence voltage generated by the fundamental frequency resonance is the power frequency of 50Hz, the fundamental frequency resonance can not be effectively identified only by analyzing the zero sequence voltage. The identification of the power frequency resonance and the single-phase earth fault is difficult, at present, the identification can be carried out only by analyzing various conditions and adding criteria under different conditions, in the embodiment, the zero sequence voltage U is detected, and meanwhile, the three-phase voltage of the 10kV A and B, C bus and the PT zero sequence current are used as auxiliary criteria, so that the identification degree of fundamental wave resonance can be effectively improved.

Therefore, in consideration of the complicated and various types of the non-ferroresonant overvoltage, the present embodiment further includes a step of performing further type identification on the non-ferroresonant overvoltage:

referring to fig. 2, after determining that the overvoltage type is the non-ferromagnetic resonance overvoltage in step 5) of this embodiment, the method further includes determining a criterion L1, and if the criterion L1 is satisfied, determining that the overvoltage type is the metallic grounding overvoltage; wherein the criterion L1 is: the ratio of the minimum amplitude to the maximum amplitude of the whole period in the three-phase voltage and the absolute error between 0 are smaller than a preset first error setting value. In this embodiment, a typical waveform diagram of the metallic grounding overvoltage is shown in fig. 7, when the metallic grounding is performed, in a measurement period, the grounding phase voltage is about 0, and the non-grounding phase voltages are approximately equal in amplitude. In this embodiment, the first error setting value is specifically 5%. After receiving a three-phase voltage of a complete period, the determination can be carried out: if the ratio of the minimum amplitude to the maximum amplitude of the whole period in the three-phase voltage and the absolute error between 0 is less than 5%, determining that the three-phase voltage is metallic grounding overvoltage; otherwise, it is determined to be non-metallic grounded (other fault types may continue to be determined).

Referring to fig. 2, in the judgment of the criterion L1 in the present embodiment, if the criterion L1 is not satisfied, the judgment further includes the judgment of the criterion L2, and if the criterion L2 is satisfied, the overvoltage type is determined to be an arc grounding overvoltage; the criterion L2 is that the ratio of the minimum amplitude to the maximum amplitude of the whole period exists in the three-phase voltage, the absolute error between 0 is smaller than a preset second error setting value, the second error setting value is larger than the first error setting value, the absolute error between the amplitudes of the other two phases of the voltage is smaller than the first error setting value, the absolute error between adjacent measuring points exists in the whole period and is larger than a third error setting value, the second error setting value can be set according to experience, for example, the value of the second error setting value is 20%, and the value of the third error setting value is 100%. The typical waveform diagram of the arc grounding overvoltage is shown in fig. 8, the arc grounding overvoltage is in one measuring period, the grounding phase voltage is smaller but larger than 0, the non-grounding phase voltage is approximately equal in amplitude, and the three-phase voltages have sudden change. Therefore, the logic for determining the arc light grounding overvoltage in this embodiment is: and (3) judging after the host receives a three-phase voltage of a complete period: firstly, whether the ratio of the minimum amplitude to the maximum amplitude of the whole period in the three-phase voltage and the absolute error between 0 is smaller than the preset 20% is determined, if yes, the following requirements are met: and meanwhile, the arc grounding overvoltage is judged if the absolute error between the amplitudes of the other two phase voltages is less than 5% and the absolute error between adjacent measuring points is more than 100% in the whole period, otherwise, other fault types are judged.

Referring to fig. 2, in the present embodiment, when the criterion L2 is judged, if the criterion L2 is not satisfied, the criterion L3 is further judged, and if the criterion L3 is satisfied, the overvoltage type is determined to be the switching-on capacitor overvoltage; wherein the criterion L3 is: and in the whole period, the absolute error between adjacent measuring points is greater than a third error setting value, the absolute error between adjacent measuring points in other parts is less than the first error setting value, and the third error setting value is greater than the second error setting value. A typical waveform diagram of the overvoltage of the closing capacitor is shown in fig. 9, the overvoltage of the closing capacitor is in a measurement period, the waveforms of three-phase voltages are regular, the amplitudes are approximately equal, and the three-phase voltages have small sudden changes. The decision logic of the overvoltage of the closing capacitor is as follows: and judging after receiving the three-phase voltage of a complete period, judging that the absolute error between adjacent measuring points in the whole period is more than 100 percent (adjustable in a procedure), and the absolute error between adjacent measuring points in other parts is less than 5 percent (adjustable in a procedure), if the absolute errors are consistent, judging that the switching-on capacitor is in overvoltage, otherwise, judging that other fault types exist.

Referring to fig. 2, in the present embodiment, when the criterion L3 is judged, if the criterion L3 is not satisfied, the judgment of the criterion L4 is further included, and if the criterion L4 is satisfied, the overvoltage type is determined to be a lightning overvoltage; wherein the criterion L4 is: in the whole period, the absolute error between adjacent measuring points is larger than a fourth error setting value, the absolute error between adjacent measuring points in other parts is smaller than the first error setting value, and the fourth error setting value is larger than the third error setting value (the value in the embodiment is 200%). The typical waveform diagram of the lightning overvoltage is shown in fig. 10, in a measurement period, the three-phase voltage waveform is regular, the amplitudes are approximately equal, and the three-phase voltage has a large mutation phenomenon. In this embodiment, the lightning overvoltage determination logic is: and after receiving the three-phase voltage of a complete period, judging that the absolute error between adjacent measuring points in the whole period is greater than 200 percent (adjustable in a program), and the absolute error between adjacent measuring points in other parts is less than 5 percent (adjustable in a program), if the absolute errors are consistent, judging the lightning overvoltage, otherwise, judging the lightning overvoltage as other fault types.

Referring to fig. 2, in the present embodiment, when the criterion L4 is judged, if the criterion L4 is not satisfied, the judgment of the criterion L5 is further included, and if the criterion L5 is satisfied, the overvoltage type is determined to be a closing no-load line overvoltage; wherein the criterion L5 is: and in the whole period, the absolute error between adjacent measuring points is greater than a fifth error setting value and occurs in a plurality of measuring points, and the fifth error setting value is greater than the first error setting value and is less than the second error setting value. A typical waveform diagram of the overvoltage of the closing no-load line is shown in fig. 11, and in a measurement period of the closing no-load line, the waveforms of three-phase voltages are relatively regular, the amplitudes are approximately equal, and the three-phase voltages all have oscillation phenomena. In this embodiment, the decision logic of the closing no-load line is as follows: and judging after receiving the three-phase voltage of a complete period, judging that the absolute error between adjacent measuring points is more than 10 percent (adjustable in program) in the whole period, and all the measuring points appear at 50, if all the measuring points accord with each other, judging that a no-load circuit is switched on, otherwise, judging that other fault types exist.

In summary, the intelligent identification method for the overvoltage of the high-voltage switch PT cabinet in the embodiment can realize intelligent identification of the frequency division ferromagnetic resonance overvoltage, the high-frequency ferromagnetic resonance overvoltage, the fundamental ferromagnetic resonance overvoltage and the non-ferromagnetic resonance overvoltage, and can improve intelligent acquisition, research and judgment identification capabilities of the overvoltage of the high-voltage PT cabinet for intelligent identification of the overvoltage of the distribution network system such as metallic grounding overvoltage, arc grounding overvoltage, switching-on capacitor overvoltage, lightning overvoltage and switching-on no-load line overvoltage by aiming at the non-ferromagnetic resonance overvoltage, so that the problems of frequent overvoltage faults, difficult overvoltage identification and difficult overvoltage suppression of the high-voltage PT cabinet are solved, and the system overvoltage can be accurately and quickly monitored and identified.

In addition, the embodiment also provides an intelligent identification device for overvoltage of a high-voltage switch PT cabinet, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the steps of the intelligent identification method for overvoltage of the high-voltage switch PT cabinet. In addition, the present embodiment also provides a computer readable storage medium, in which a computer program programmed or configured to execute the foregoing intelligent identification method for overvoltage of a high-voltage switch PT cabinet is stored.

As shown in fig. 3, the embodiment further provides an intelligent identification system for overvoltage of high-voltage switch PT cabinet for applying the above intelligent identification method for overvoltage of high-voltage switch PT cabinet, which includes a broadband sensing support insulator 1, a PT full-frequency zero-sequence current monitoring unit 2, a PT full-frequency zero-sequence current edge processing unit 3, a full-wave voltage converting unit 4, a real-time voltage monitoring module 5, a data remote transmission module 6 and an overvoltage identification device 7, wherein the broadband sensing support insulator 1 is disposed in the detected high-voltage switch PT cabinet, an output end of the broadband sensing support insulator 1 is connected to the data remote transmission module 6 through the full-wave voltage converting unit 4 and the real-time voltage monitoring module 5 in sequence, the PT full-frequency zero-sequence current monitoring unit 2 is used for detecting the PT full-frequency zero-sequence current in the detected high-voltage switch cabinet, an output end of the PT full-frequency zero-sequence current monitoring unit 2 is connected to the data remote transmission module 6 through the PT full-frequency zero-sequence current edge processing unit 3, the output end of the data remote transmission module 6 is connected with the overvoltage identification device 7 through a network.

In the embodiment, the broadband sensing supporting insulator 1 comprises the integration of supporting insulation and broadband overvoltage monitoring functions, the broadband sensing supporting insulator 1 is a non-traditional voltage transformer capable of covering measurement and protection ranges, the broadband sensing supporting insulator 1 adopts a thin film capacitor or a ceramic capacitor, the requirements of reliable operation for 10 years and unchanged measurement precision can be met, all error requirements of a rated primary voltage measurement level and a rated protection level can be met, the rated primary voltage comprises a rated phase voltage and a rated zero-sequence voltage, and the standard value is 10 kV/; the rated secondary phase voltage standard value is 3.25V/, and the rated secondary zero sequence voltage standard value is 6.5V/3; the broadband sensing support insulator 1 is arranged in a rear lower cabinet of a high-voltage switch PT cabinet, a copper bar is led out from the lower end of a PT isolation handcart of the high-voltage switch PT cabinet at the high-voltage side and is connected with a low-voltage signal output by a full-wave voltage conversion unit 4 at the low-voltage side, and the overvoltage signal can be collected for overvoltage identification.

In the embodiment, the PT full-frequency zero-sequence current monitoring unit 2 is used for monitoring the leakage current of the resonance elimination device, neutral point current is collected in a core penetrating mode (installed at the tail of the primary resonance elimination device), the requirements on balance characteristics, interference resistance and linearity are met, the measurement range is 50mA-1A, the ratio difference is less than or equal to 0.25%, the phase difference is less than or equal to 30 minutes, rated output is 0-2V (AC), the zero-sequence current of the PT neutral point can be effectively measured, and overvoltage identification can be completed in an auxiliary mode.

In this embodiment, the PT full-frequency zero-sequence current edge processing unit 3 is configured to process and analyze the neutral point current collected by the PT full-frequency zero-sequence current monitoring unit, extract key information of the amplitude and the phase of the neutral point current, distinguish and screen the interference signal and the bleed-off current signal, and have a 256Mb storage function. The working voltage is 3-3.6V, and the working temperature is 0-70 ℃. The volume is small, the power consumption is low, the operation is stable, the low-power-consumption switching-off function is realized, and the data transmission rate in the electric noise environment can reach 6 Mbps.

In this embodiment, the full-wave voltage conversion unit 4 can collect the full-frequency-domain voltage signal within the range of 1Hz to 10kHz, and simultaneously, the voltage amplitude is collected by voltage conversion, and the voltage conversion rate parameter is adjustable in multiple steps.

In this embodiment, the real-time voltage monitoring module 5 is configured to collect the voltage signal of the full-wave voltage conversion unit 4, and according to actual needs, the collection resolution is controllable, the single collection window is adjustable, and the real-time voltage monitoring module also has a certain storage function, and the capacity of the memory can reach 256MB, and has an automatic memory updating function, and is more stable during data access.

In this embodiment, the data remote transmission module 6 can adopt various existing data remote transmission terminals as required, and can adopt wifi or lora communication mode as required to transmit signals to the overvoltage identification device 7.

In this embodiment, the overvoltage identification device 7 comprises a microprocessor and a memory which are connected with each other, and the microprocessor is programmed or configured to execute the steps of the intelligent overvoltage identification method for the high-voltage switch PT cabinet. The overvoltage identification device 7 may be a common computer device, or may be a computer of a monitoring center, or a cloud server.

In this embodiment, the overvoltage identification device 7 is a computer of a monitoring center. As shown in fig. 3, the overvoltage identification device 7 is further connected to a man-machine module 71, an internet of things module 72 and a power supply module 73. Wherein: the man-machine module 71 is used for realizing man-machine interaction with the overvoltage identification device 7, for example, setting various setting value parameters and the like; the internet of things module 72 is configured to implement the internet of things result of the overvoltage identification device 7, and the power supply module 73 is configured to implement power supply of the overvoltage identification device 7. Since the human-machine module 71, the internet of things module 72 and the power module 73 are all existing functional modules, detailed circuit structures thereof will not be described herein.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present application is directed to methods, apparatus (systems), and computer program products according to embodiments of the application, wherein the instructions that execute via the flowcharts and/or processor of the computer program product create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.