Single-phase earth fault property analysis method and system
By comparing the waveform phases of the ground fault recordings of transmission lines, the direction, location, and cause of single-phase ground faults can be determined, enabling a detailed analysis of the nature of single-phase ground faults.
Patent Information
- Application Number
- CN202511123493.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies lack detailed analysis of the characteristics of single-phase grounding faults, such as their direction, location, and cause.
By acquiring the three-phase current waveform, three-phase voltage waveform, zero-sequence current waveform, and zero-sequence voltage waveform of the transmission line from the ground fault recording diagram, and performing phase comparison, the direction, cause, and location of the single-phase ground fault can be determined.
It can quickly analyze the direction, location and cause of single-phase grounding faults, solving the lack of analysis in existing technologies.
Smart Images
Figure CN120993265A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of power system fault detection, in particular to a single-phase grounding fault property analysis method and system. BACKGROUND
[0002] Power systems will occur in the process of running a variety of faults, including single-phase grounding fault, phase-to-phase fault, phase-to-ground fault, three-phase fault and broken line fault, etc.
[0003] However, most of the current professional analysis only stays in the simple judgment stage of the above faults, but does not analyze the nature of the above faults (including the occurrence direction, occurrence location and occurrence cause, etc.), especially the most common single-phase grounding fault. Therefore, there is an urgent need for a single-phase grounding fault property analysis method that can analyze the nature of single-phase grounding fault in terms of occurrence direction, occurrence location and occurrence cause, etc. SUMMARY
[0004] The technical problem to be solved by the embodiments of the present application is to provide a single-phase grounding fault property analysis method and system, which can solve the problem of lack of analysis of the occurrence direction, occurrence location and occurrence cause of single-phase grounding fault in the prior art.
[0005] To solve the above technical problems, the embodiments of the present application provide a single-phase grounding fault property analysis method, which comprises the following steps:
[0006] Under the working condition of single-phase grounding fault of the power transmission line, the three-phase current waveform of the power transmission line, the three-phase voltage waveform of the power transmission line, the zero sequence current waveform and the zero sequence voltage waveform formed on the grounding fault recording waveform of the power transmission line are obtained;
[0007] According to the three-phase current waveform of the power transmission line and the three-phase voltage waveform of the power transmission line, the fault phase current waveform and the fault phase voltage waveform are determined respectively, and the occurrence direction of the single-phase grounding fault is determined in combination with the zero sequence current waveform and the zero sequence voltage waveform.
[0008] If the phase of the zero sequence current leads the phase of the zero sequence voltage by more than a preset first angle value or the phase of the fault phase current lags the phase of the fault phase voltage between a preset second angle value and a preset third angle value, the occurrence direction of the single-phase grounding fault is determined to be positive.
[0009] If the phase of the zero sequence current leads the phase of the zero sequence voltage by less than the first angle value, and the phase of the fault phase current lags the phase of the fault phase voltage by less than the second angle value or more than the third angle value, the occurrence direction of the single-phase grounding fault is determined to be negative.
[0010] wherein the method further comprises:
[0011] from the three-phase voltage waveform of the power transmission line, the hysteresis phase voltage waveform and the leading phase voltage waveform corresponding to the fault phase are obtained, and the occurrence cause of the single-phase grounding fault is determined in combination with the fault phase current waveform, the fault phase voltage waveform, the zero-sequence current waveform and the zero-sequence voltage waveform;
[0012] wherein if the phase of the fault phase current lags behind the phase of the fault phase voltage by more than the second angle value and less than the fourth angle value, or if the phase difference between the fault phase voltage and the zero-sequence voltage is not equal to the fifth angle value, or if the amplitude variation region of the hysteresis phase voltage wave is greater than that of the leading phase voltage wave, it is determined that the occurrence cause of the single-phase grounding fault is caused by the overvoltage grounding; the fourth angle value is less than the third angle value;
[0013] wherein if the phase of the fault phase current lags behind the phase of the fault phase voltage by more than the fourth angle value, the phase difference between the fault phase voltage and the zero-sequence voltage is equal to the fifth angle value, and the amplitude variation of the hysteresis phase voltage is less than that of the leading phase voltage, it is determined that the occurrence cause of the single-phase grounding fault is caused by the metallic grounding.
[0014] wherein the method further comprises:
[0015] when one end of the power transmission line is designated as a measurement end, the voltage waveform and the current waveform of the corresponding fault phase at the measurement end are obtained, and the occurrence position of the corresponding cause of the single-phase grounding fault is determined in combination with the occurrence cause of the single-phase grounding fault;
[0016] wherein when the occurrence cause of the single-phase grounding fault is caused by the metallic grounding, if the voltage amplitude of the corresponding fault phase at the measurement end is 0 according to the voltage waveform of the corresponding fault phase at the measurement end, it is determined that the position causing the metallic grounding fault is at the designated measurement end of the power transmission line; or, if the voltage amplitude of the corresponding fault phase at the measurement end is greater than 0 and less than a first voltage threshold and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase at the measurement end is between a sixth angle value and a seventh angle value according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the position causing the metallic grounding fault is at the middle of the power transmission line; or, if the voltage amplitude of the corresponding fault phase at the measurement end is greater than a second voltage threshold and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase at the measurement end is between the sixth angle value and the seventh angle value according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the position causing the metallic grounding fault is at the other end of the power transmission line relatively far away from the measurement end.
[0017] wherein, when the single-phase grounding fault is caused by the over-resistance grounding, if according to the voltage waveform and the current waveform of the corresponding fault phase on the measuring terminal, it is determined that the position of the over-resistance grounding fault occurs at the designated measuring terminal on the power transmission line, when the voltage amplitude of the corresponding fault phase on the measuring terminal is not 0 and the phase between the voltage waveform and the current waveform of the corresponding fault phase is the same; or, if according to the voltage waveform and the current waveform of the corresponding fault phase on the measuring terminal, it is determined that the position of the over-resistance grounding fault occurs at the middle of the power transmission line, when the voltage amplitude of the corresponding fault phase on the measuring terminal is greater than 0 and less than the first voltage threshold value and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is less than the eighth angle value.
[0018] wherein, the first angle value is 100 0 ; the second angle value is 0 0 ; the third angle value is 80 0 ; the fourth angle value is 15 0 ; the fifth angle value is 180 0 ; the sixth angle value is 78 0 ; the seventh angle value is 81 0 ; and the eighth angle value is 15 0 .
[0019] The embodiment of the present application also provides a single-phase grounding fault property analysis system, comprising:
[0020] a power transmission line grounding fault recording graph acquisition unit, configured to acquire three-phase current waveforms, three-phase voltage waveforms, zero sequence current waveforms and zero sequence voltage waveforms of a power transmission line formed on a power transmission line grounding fault recording graph under the working condition that a single-phase grounding fault occurs in the power transmission line;
[0021] a fault occurrence direction analysis unit, configured to determine fault phase current waveforms and fault phase voltage waveforms respectively according to the three-phase current waveforms and the three-phase voltage waveforms of the power transmission line, and determine the occurrence direction of the single-phase grounding fault in combination with the zero sequence current waveforms and the zero sequence voltage waveforms;
[0022] wherein, if the phase of the zero sequence current is ahead of the phase of the zero sequence voltage by more than a preset first angle value or the phase of the fault phase current lags behind the phase of the fault phase voltage between a preset second angle value and a preset third angle value, it is determined that the occurrence direction of the single-phase grounding fault is a positive direction;
[0023] If the phase of the zero-sequence current is compared to be ahead of the phase of the zero-sequence voltage by an angle less than the first angle value, and the phase of the fault-phase current is compared to be behind the phase of the fault-phase voltage by an angle less than the second angle value or greater than the third angle value, it is determined that the occurrence direction of the single-phase grounding fault is the reverse direction.
[0024] The method further comprises:
[0025] The fault occurrence cause analysis unit is configured to acquire a lagging-phase voltage waveform and a leading-phase voltage waveform corresponding to the fault phase from the three-phase voltage waveform of the power transmission line, and determine the occurrence cause of the single-phase grounding fault in combination with the fault-phase current waveform, the fault-phase voltage waveform, the zero-sequence current waveform and the zero-sequence voltage waveform.
[0026] If the phase of the fault-phase current is compared to be behind the phase of the fault-phase voltage by an angle greater than the second angle value and less than the fourth angle value, or the phase difference between the fault-phase voltage and the zero-sequence voltage is compared to be not equal to a preset fifth angle value, or the amplitude variation range of the lagging-phase voltage waveform is compared to be greater than the amplitude variation range of the leading-phase voltage waveform, it is determined that the occurrence cause of the single-phase grounding fault is caused by passing through a resistance grounding; and the fourth angle value is less than the third angle value.
[0027] If the phase of the fault-phase current is compared to be behind the phase of the fault-phase voltage by an angle greater than the fourth angle value, the phase difference between the fault-phase voltage and the zero-sequence voltage is equal to the fifth angle value, and the amplitude variation of the lagging-phase voltage is compared to be less than the amplitude variation of the leading-phase voltage, it is determined that the occurrence cause of the single-phase grounding fault is caused by passing through a metallic grounding.
[0028] The method further comprises:
[0029] The fault occurrence position analysis unit is configured to acquire a voltage waveform and a current waveform of the fault phase at a measurement end of the power transmission line, and determine the occurrence position of the single-phase grounding fault corresponding to the occurrence cause in combination with the occurrence cause of the single-phase grounding fault.
[0030] If the voltage waveform of the corresponding fault phase on the measurement end is obtained according to the voltage waveform of the corresponding fault phase on the measurement end, the voltage amplitude of the corresponding fault phase on the measurement end is 0, it is determined that the position causing the metallic ground fault occurs at the designated measurement end on the power transmission line; or, if the voltage waveform of the corresponding fault phase on the measurement end and the current waveform are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than 0 and less than the first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between the sixth angle value and the seventh angle value, it is determined that the position causing the metallic ground fault occurs at the middle of the power transmission line; or, if the voltage waveform of the corresponding fault phase on the measurement end and the current waveform are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than the second voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between the sixth angle value and the seventh angle value, it is determined that the position causing the metallic ground fault occurs at the other end of the power transmission line relatively far away from the measurement end.
[0031] If the voltage waveform of the corresponding fault phase on the measurement end and the current waveform are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is not 0, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is the same, it is determined that the position causing the excessive resistance ground fault occurs at the designated measurement end on the power transmission line; or, if the voltage waveform of the corresponding fault phase on the measurement end and the current waveform are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than 0 and less than the first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is less than the eighth angle value, it is determined that the position causing the excessive resistance ground fault occurs at the middle of the power transmission line.
[0032] The first angle value is 100 0 The second angle value is 0 0 The third angle value is 80 0 The fourth angle value is 15 0 The fifth angle value is 180 0 The sixth angle value is 78 0 The seventh angle value is 81 0 The eighth angle value is 15 0 .
[0033] The embodiment of the present application has the following beneficial effects:
[0034] The application is based on the three-phase current waveform of a transmission line, the three-phase voltage waveform of the transmission line, the zero sequence current waveform and the zero sequence voltage waveform formed on a transmission line grounding fault recording graph, phase comparison between different waveforms is performed, the occurrence direction, occurrence position and occurrence cause of single-phase grounding fault are quickly analyzed, and thus the problem that the occurrence direction, occurrence position and occurrence cause of single-phase grounding fault are not analyzed in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS
[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor.
[0036] Figure 1 A flow chart of a single-phase grounding fault property analysis method provided by the embodiment of the present application;
[0037] Figure 2 A structural schematic diagram of a single-phase grounding fault property analysis system provided by the embodiment of the present application. DETAILED DESCRIPTION
[0038] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings.
[0039] As shown in Figure 1 A single-phase grounding fault property analysis method provided by the embodiment of the present application, the method comprises the following steps:
[0040] Step S1, under the working condition that a single-phase grounding fault occurs in a transmission line, the three-phase current waveform of the transmission line, the three-phase voltage waveform of the transmission line, the zero sequence current waveform and the zero sequence voltage waveform formed on a transmission line grounding fault recording graph are obtained;
[0041] The specific process is as follows. First, the working condition that a single-phase grounding fault occurs in a transmission line is judged based on a transmission line grounding fault recording graph, specifically: only one phase voltage amplitude is reduced in three-phase voltage, and the amplitudes and phases of the other two phases are almost unchanged, and zero sequence voltage occurs. At this time, the current amplitude of the voltage amplitude reduction phase is increased at the same time as the voltage reduction, and zero sequence current occurs, and the size and phase of the zero sequence current are the same as the current amplitude and phase of the increased phase. Therefore, the current of the fault phase is increased and the voltage is reduced. It should be noted that the transmission line grounding fault recording graph is a commonly used view in the art, and is not shown here.
[0042] Secondly, in the single-phase-to-ground fault condition, the three-phase current waveform of the transmission line, the three-phase voltage waveform of the transmission line, the zero-sequence current waveform and the zero-sequence voltage waveform are extracted from the ground fault recording graph of the transmission line, so as to be used for analyzing the occurrence direction, the occurrence position and the occurrence cause of the single-phase-to-ground fault.
[0043] In step S2, the fault-phase current waveform and the fault-phase voltage waveform are determined according to the three-phase current waveform of the transmission line and the three-phase voltage waveform of the transmission line, and the occurrence direction of the single-phase-to-ground fault is determined in combination with the zero-sequence current waveform and the zero-sequence voltage waveform.
[0044] If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by more than a preset first angle value or the phase of the fault-phase current lags the phase of the fault-phase voltage between a preset second angle value and a preset third angle value, the occurrence direction of the single-phase-to-ground fault is determined to be a positive direction.
[0045] If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by less than the first angle value, and the phase of the fault-phase current lags the phase of the fault-phase voltage by less than the second angle value or more than the third angle value, the occurrence direction of the single-phase-to-ground fault is determined to be a reverse direction.
[0046] Specifically, the occurrence direction of the single-phase-to-ground fault is determined according to the fault-phase current, the fault-phase voltage, the zero-sequence current and the zero-sequence voltage extracted from the three-phase current waveform of the transmission line, the three-phase voltage waveform of the transmission line, the zero-sequence current waveform and the zero-sequence voltage waveform, i.e., whether the single-phase-to-ground fault is a positive direction fault or a reverse direction fault.
[0047] At this time, condition one is met: the phase of the zero-sequence current leads the phase of the zero-sequence voltage by more than a preset first angle value (e.g., 100 0 ); or, condition two is met: the phase of the fault-phase current lags the phase of the fault-phase voltage between a preset second angle value (e.g., 0 0 ) and a preset third angle value (e.g., 80 0 ); therefore, the occurrence direction of the single-phase-to-ground fault is determined to be a positive direction, i.e., a positive direction fault.
[0048] On the contrary, if neither condition one nor condition two is met, i.e., the phase of the zero-sequence current leads the phase of the zero-sequence voltage by less than the first angle value (e.g., 100 0 ), and the phase of the fault-phase current lags the phase of the fault-phase voltage by less than the second angle value (e.g., 0 0 ) or more than the third angle value (e.g., 80 0 ), the occurrence direction of the single-phase-to-ground fault is determined to be a reverse direction, i.e., a reverse direction fault.
[0049] It should be noted that the phase of the lead and lag is the change of the alternating current, the first to reach zero (or maximum value) relative to the starting point of timing (t=0) is called the lead, and the latter is called the lag.
[0050] In the embodiment of the present application, the method further comprises: obtaining the lagging phase voltage waveform and the leading phase voltage waveform corresponding to the fault phase from the three-phase voltage waveform of the power transmission line, and combining the fault phase current waveform, the fault phase voltage waveform, the zero sequence current waveform and the zero sequence voltage waveform to determine the cause of the single-phase ground fault.
[0051] At this time, condition three is met: the phase of the fault phase current lags the phase of the fault phase voltage by more than a second angle value (such as 0 0 ) and less than a fourth angle value (such as 15 0 ), that is, significantly less than a third angle value (such as 80 0 ); or, condition four is met: the phase difference between the fault phase voltage and the zero sequence voltage is not equal to a preset fifth angle value (such as 180 0 ); or, condition five is met: the amplitude variation region of the lagging phase voltage wave is greater than that of the leading phase voltage wave, that is, the two non-phase fault voltages appear non-symmetrical variation and the amplitude variation of the lagging phase voltage of the fault phase is greater than that of the leading phase; therefore, it is determined that the cause of the single-phase ground fault is caused by the through resistance grounding.
[0052] On the contrary, if conditions three to five are not met, that is, the phase of the fault phase current lags the phase of the fault phase voltage by more than the fourth angle value (such as 15 0 ), the phase difference between the fault phase voltage and the zero sequence voltage is equal to the fifth angle value (such as 180 0 ), and the lagging phase voltage amplitude variation is less than the leading phase voltage amplitude variation, it is determined that the cause of the single-phase ground fault is caused by the metallic grounding.
[0053] In the embodiment of the present application, the method further comprises: when one end of the power transmission line is designated as a measurement end, obtaining the voltage waveform and the current waveform of the corresponding fault phase on the measurement end, and combining the cause of the single-phase ground fault to determine the occurrence position of the corresponding cause of the single-phase ground fault, including the first end, the middle and the end of the power transmission line.
[0054] For example, when the cause of the single-phase ground fault is caused by metallic grounding, if the voltage amplitude of the corresponding fault phase on the measurement end is 0 according to the voltage waveform of the corresponding fault phase on the measurement end, it is determined that the position causing the metallic ground fault is at the designated measurement end of the power transmission line, that is, the fault phase voltage measured by the measurement end of the power transmission line is 0, and it is judged that the metallic ground fault of the first end of the power transmission line.
[0055] For example, when the single-phase grounding fault is caused by metallic grounding, if the voltage waveform and the current waveform of the corresponding fault phase on the measurement end are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than 0 and less than a first voltage threshold (e.g., 3V), and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between a sixth angle value (e.g., 78 0 ) and a seventh angle value (e.g., 81 0 ), it is determined that the location causing the metallic grounding fault is in the middle of the power transmission line, i.e., the fault voltage measured by the measurement end of the power transmission line is small, and the phase of the fault current is about 80 0 , the metallic grounding fault in the middle of the power transmission line is determined.
[0056] For example, when the single-phase grounding fault is caused by metallic grounding, if the voltage waveform and the current waveform of the corresponding fault phase on the measurement end are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than a second voltage threshold (e.g., 380V), and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between the sixth angle value (e.g., 78 0 ) and the seventh angle value (e.g., 81 0 ), it is determined that the location causing the metallic grounding fault is at the other end of the power transmission line relative to the measurement end, i.e., the fault voltage measured by the measurement end of the power transmission line is large, and the phase of the fault current is about 80 0 , the metallic grounding fault at the end of the power transmission line is determined.
[0057] For example, when the single-phase grounding fault is caused by excessive resistance grounding, if the voltage waveform and the current waveform of the corresponding fault phase on the measurement end are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is not 0, and the phase of the voltage waveform and the current waveform of the corresponding fault phase is the same, it is determined that the location causing the excessive resistance grounding fault is at the designated measurement end of the power transmission line, i.e., the fault phase voltage measured by the measurement end of the power transmission line is not 0, and the phase of the fault phase current is the same, the excessive resistance grounding fault at the first end of the power transmission line is determined.
[0058] For example, when the single-phase grounding fault is caused by excessive resistance grounding, if the voltage waveform and the current waveform of the corresponding fault phase on the measurement end are obtained, the voltage amplitude of the corresponding fault phase on the measurement end is greater than 0 and less than a first voltage threshold (e.g., 3V), and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is less than a preset eighth angle value (e.g., 15 0 ), it is determined that the location causing the excessive resistance grounding fault is in the middle of the power transmission line, i.e., the fault voltage measured by the measurement end of the power transmission line is small, and the phase of the fault current is significantly less than 80 0If the phase of the zero sequence current is ahead of the phase of the zero sequence voltage by more than a first angle value, or the phase of the fault phase current lags behind the phase of the fault phase voltage between a second angle value and a third angle value, it is determined that the single-phase grounding fault is in a positive direction.
[0059] As shown in the figure, a single-phase grounding fault property analysis system provided in an embodiment of the application includes: Figure 2
[0060] The power transmission line grounding fault recording graph acquisition unit 110 is configured to acquire three-phase current waveforms, three-phase voltage waveforms, zero sequence current waveforms and zero sequence voltage waveforms formed on a power transmission line grounding fault recording graph under a single-phase grounding fault condition of the power transmission line.
[0061] The fault occurrence direction analysis unit 120 is configured to determine fault phase current waveforms and fault phase voltage waveforms respectively according to the three-phase current waveforms and the three-phase voltage waveforms of the power transmission line, and determine the occurrence direction of the single-phase grounding fault in combination with the zero sequence current waveforms and the zero sequence voltage waveforms.
[0062] If the phase of the zero sequence current is ahead of the phase of the zero sequence voltage by more than a first angle value, or the phase of the fault phase current lags behind the phase of the fault phase voltage between a second angle value and a third angle value, it is determined that the single-phase grounding fault is in a positive direction.
[0063] If the phase of the zero sequence current is ahead of the phase of the zero sequence voltage by less than the first angle value, and the phase of the fault phase current lags behind the phase of the fault phase voltage between the second angle value and the third angle value, it is determined that the single-phase grounding fault is in a reverse direction.
[0064] The single-phase grounding fault property analysis system further includes:
[0065] The fault occurrence cause analysis unit is configured to acquire lagging phase voltage waveforms and leading phase voltage waveforms corresponding to the fault phase from the three-phase voltage waveforms of the power transmission line, and determine the occurrence cause of the single-phase grounding fault in combination with the fault phase current waveforms, the fault phase voltage waveforms, the zero sequence current waveforms and the zero sequence voltage waveforms.
[0066] If the phase of the fault phase current lags behind the phase of the fault phase voltage by more than the second angle value and less than a fourth angle value, or the phase difference between the fault phase voltage and the zero sequence voltage is not equal to a fifth angle value, or the amplitude variation region of the lagging phase voltage wave is greater than that of the leading phase voltage wave, it is determined that the occurrence cause of the single-phase grounding fault is caused by excessive resistance grounding; the fourth angle value is less than the third angle value.
[0067] If the phase of the fault phase current lags behind the phase of the fault phase voltage by more than the fourth angle value, the phase difference between the fault phase voltage and the zero sequence voltage is equal to the fifth angle value, and the change in the amplitude of the lagging phase voltage is smaller than the change in the amplitude of the leading phase voltage, it is determined that the single-phase grounding fault is caused by metallic grounding.
[0068] In addition, the application further comprises:
[0069] The fault location analysis unit is configured to, when the one end of the power transmission line is designated as a measurement end, acquire the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, and determine the location of the corresponding cause of the single-phase grounding fault according to the cause of the single-phase grounding fault.
[0070] If the cause of the single-phase grounding fault is metallic grounding, if the voltage amplitude of the corresponding fault phase at the measurement end is 0 according to the voltage waveform of the corresponding fault phase at the measurement end, it is determined that the location of the metallic grounding fault is at the designated measurement end of the power transmission line; or, if the voltage amplitude of the corresponding fault phase at the measurement end is greater than 0 and less than a first voltage threshold value, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between a sixth angle value and a seventh angle value according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the location of the metallic grounding fault is at the middle part of the power transmission line; or, if the voltage amplitude of the corresponding fault phase at the measurement end is greater than a second voltage threshold value, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is between the sixth angle value and the seventh angle value according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the location of the metallic grounding fault is at the other end of the power transmission line that is relatively far away from the measurement end.
[0071] If the cause of the single-phase grounding fault is over-resistance grounding, if the voltage amplitude of the corresponding fault phase at the measurement end is not 0, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is the same according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the location of the over-resistance grounding fault is at the designated measurement end of the power transmission line; or, if the voltage amplitude of the corresponding fault phase at the measurement end is greater than 0 and less than the first voltage threshold value, and the phase difference between the voltage waveform and the current waveform of the corresponding fault phase is less than a preset eighth angle value according to the voltage waveform and the current waveform of the corresponding fault phase at the measurement end, it is determined that the location of the over-resistance grounding fault is at the middle part of the power transmission line.
[0072] The first angle value is 100 0 ; and the second angle value is 00 ; the third angle value is 80 0 ; the fourth angle value is 15 0 ; the fifth angle value is 180 0 ; the sixth angle value is 78 0 ; the seventh angle value is 81 0 ; the eighth angle value is 15 0 .
[0073] The embodiments of the present application have the following beneficial effects:
[0074] The present application is based on the three-phase current waveform of a transmission line, the three-phase voltage waveform of a transmission line, the zero-sequence current waveform and the zero-sequence voltage waveform formed on a transmission line grounding fault recording graph, and the phase comparison between different waveforms, so that the occurrence direction, occurrence position and occurrence cause of single-phase grounding fault can be quickly analyzed, thereby solving the problem that the occurrence direction, occurrence position and occurrence cause of single-phase grounding fault cannot be analyzed in the prior art.
[0075] Those skilled in the art can understand that all or part of the steps of the above-mentioned embodiment methods can be completed by programs instructing related hardware, and the programs can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc.
[0076] The above only discloses the preferred embodiments of the present application, and of course cannot limit the scope of the present application, so equivalent changes made according to the claims of the present application are still within the scope of the present application.
Claims
1. A method for analyzing the characteristics of a single-phase ground fault, characterized in that, The method includes the following steps: Under the condition of a single-phase ground fault in a transmission line, the waveforms of the three-phase current, three-phase voltage, zero-sequence current, and zero-sequence voltage of the transmission line formed on the ground fault waveform recorder are obtained. Based on the three-phase current waveform and the three-phase voltage waveform of the transmission line, the fault phase current waveform and the fault phase voltage waveform are determined respectively. Combined with the zero-sequence current waveform and the zero-sequence voltage waveform, the direction of occurrence of the single-phase grounding fault is determined. If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by more than a preset first angle value, or if the phase of the fault phase current lags the phase of the fault phase voltage and is located between a preset second angle value and a preset third angle value, then the direction of occurrence of the single-phase ground fault is determined to be the positive direction. If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by less than the first angle value, and the phase of the fault phase current lags the phase of the fault phase voltage by less than the second angle value or greater than the third angle value, then the direction of occurrence of the single-phase ground fault is determined to be the opposite direction.
2. The method for analyzing the nature of a single-phase ground fault as described in claim 1, characterized in that, The method further includes: From the three-phase voltage waveforms of the transmission line, the lagging phase voltage waveform and the leading phase voltage waveform corresponding to the fault phase are obtained, and combined with the fault phase current waveform, the fault phase voltage waveform, the zero-sequence current waveform and the zero-sequence voltage waveform, the cause of the single-phase grounding fault is determined. Specifically, if the phase lag of the fault phase current behind the phase lag of the fault phase voltage is greater than the second angle value and less than the fourth angle value; or, if the phase difference between the fault phase voltage and the zero-sequence voltage is not equal to the preset fifth angle value; or, if the amplitude change region of the lagging phase voltage wave is greater than the amplitude change region of the leading phase voltage wave, then it is determined that the single-phase grounding fault was caused by grounding through a resistance; the fourth angle value is less than the third angle value. If the phase of the fault phase current lags the phase of the fault phase voltage by more than the fourth angle value, the phase difference between the fault phase voltage and the zero-sequence voltage is equal to the fifth angle value, and the change in the amplitude of the lagging phase voltage is less than the change in the amplitude of the leading phase voltage, then it is determined that the single-phase grounding fault was caused by metallic grounding.
3. The method for analyzing the nature of a single-phase ground fault as described in claim 2, characterized in that, The method further includes: When one end of the transmission line is designated as the measuring end, the voltage waveform and current waveform of the corresponding fault phase on the measuring end are obtained, and the location of the occurrence of the corresponding cause of the single-phase grounding fault is determined in combination with the cause of the single-phase grounding fault. Specifically, when a single-phase ground fault is caused by a metallic grounding, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is 0 based on the voltage waveform of the faulty phase at the measuring terminal, then the location causing the metallic ground fault is determined to be at the designated measuring terminal on the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than 0 and less than a first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is between a preset sixth angle value and a seventh angle value, then the location causing the metallic ground fault is determined to be in the middle of the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than a second voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is between the sixth angle value and the seventh angle value, then the location causing the metallic ground fault is determined to be at the other end of the transmission line relatively far from the measuring terminal. Specifically, when a single-phase ground fault is caused by over-resistance grounding, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is not zero and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is the same, then the location causing the over-resistance grounding fault is determined to be at the designated measuring terminal on the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than zero and less than the first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is less than a preset eighth angle value, then the location causing the over-resistance grounding fault is determined to be in the middle of the transmission line.
4. The method for analyzing the nature of a single-phase ground fault as described in claim 3, characterized in that, The first angle value is 100. 0 The second angle value is 0. 0 The third angle value is 80°. 0 The fourth angle value is 15. 0 The fifth angle value is 180°. 0 The sixth angle value is 78. 0 The seventh angle value is 81. 0 The eighth angle value is 15. 0 .
5. A system for analyzing the characteristics of a single-phase ground fault, characterized in that, include: The transmission line ground fault waveform acquisition unit is used to acquire the three-phase current waveform, three-phase voltage waveform, zero-sequence current waveform, and zero-sequence voltage waveform formed on the transmission line ground fault waveform when a single-phase ground fault occurs in the transmission line. The fault occurrence direction analysis unit is used to determine the fault phase current waveform and fault phase voltage waveform based on the three-phase current waveform and the three-phase voltage waveform of the transmission line, and to determine the occurrence direction of the single-phase grounding fault by combining the zero-sequence current waveform and the zero-sequence voltage waveform. If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by more than a preset first angle value, or if the phase of the fault phase current lags the phase of the fault phase voltage and is located between a preset second angle value and a preset third angle value, then the direction of occurrence of the single-phase ground fault is determined to be the positive direction. If the phase of the zero-sequence current leads the phase of the zero-sequence voltage by less than the first angle value, and the phase of the fault phase current lags the phase of the fault phase voltage by less than the second angle value or greater than the third angle value, then the direction of occurrence of the single-phase ground fault is determined to be the opposite direction.
6. The single-phase ground fault nature analysis system as described in claim 5, characterized in that, Also includes: The fault occurrence cause analysis unit is used to obtain the lagging phase voltage waveform and the leading phase voltage waveform corresponding to the fault phase from the three-phase voltage waveform of the transmission line, and combine the fault phase current waveform, the fault phase voltage waveform, the zero-sequence current waveform and the zero-sequence voltage waveform to determine the cause of the single-phase grounding fault. Specifically, if the phase lag of the fault phase current behind the phase lag of the fault phase voltage is greater than the second angle value and less than the fourth angle value; or, if the phase difference between the fault phase voltage and the zero-sequence voltage is not equal to the preset fifth angle value; or, if the amplitude change region of the lagging phase voltage wave is greater than the amplitude change region of the leading phase voltage wave, then it is determined that the single-phase grounding fault was caused by grounding through a resistance; the fourth angle value is less than the third angle value. If the phase of the fault phase current lags the phase of the fault phase voltage by more than the fourth angle value, the phase difference between the fault phase voltage and the zero-sequence voltage is equal to the fifth angle value, and the change in the amplitude of the lagging phase voltage is less than the change in the amplitude of the leading phase voltage, then it is determined that the single-phase grounding fault was caused by metallic grounding.
7. The single-phase ground fault nature analysis system as described in claim 6, characterized in that, Also includes: The fault location analysis unit is used to acquire the voltage and current waveforms of the corresponding fault phase at a specified end of the transmission line when one end is designated as the measurement end, and determine the location of the occurrence of the corresponding cause of the single-phase grounding fault in combination with the cause of the single-phase grounding fault. Specifically, when a single-phase ground fault is caused by a metallic grounding, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is 0 based on the voltage waveform of the faulty phase at the measuring terminal, then the location causing the metallic ground fault is determined to be at the designated measuring terminal on the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than 0 and less than a first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is between a preset sixth angle value and a seventh angle value, then the location causing the metallic ground fault is determined to be in the middle of the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than a second voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is between the sixth angle value and the seventh angle value, then the location causing the metallic ground fault is determined to be at the other end of the transmission line relatively far from the measuring terminal. Specifically, when a single-phase ground fault is caused by over-resistance grounding, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is not zero and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is the same, then the location causing the over-resistance grounding fault is determined to be at the designated measuring terminal on the transmission line; or, if the voltage amplitude of the corresponding faulty phase at the measuring terminal is greater than zero and less than the first voltage threshold, and the phase difference between the voltage waveform and the current waveform of the corresponding faulty phase is less than a preset eighth angle value, then the location causing the over-resistance grounding fault is determined to be in the middle of the transmission line.
8. The single-phase ground fault nature analysis system as described in claim 7, characterized in that, The first angle value is 100. 0 The second angle value is 0. 0 The third angle value is 80°. 0 The fourth angle value is 15. 0 The fifth angle value is 180°. 0 The sixth angle value is 78. 0 The seventh angle value is 81. 0 The eighth angle value is 15. 0 .