A GIS device internal transient arc on-line monitoring method and system

Abstract

The application discloses a GIS device internal transient arc online monitoring method and system, comprising: arranging GIS device internal sensor measuring points of an extra-high voltage substation; obtaining transient voltages at each measuring point during a handover withstand voltage test and an operation process; determining whether a ground breakdown transient arc occurs based on the transient voltages; when it is determined that the ground breakdown transient arc occurs, positioning the GIS device internal transient arc based on the transient voltages to determine a fault position; wherein the arranging GIS device internal sensor measuring points of an extra-high voltage substation comprises: arranging measuring points on the left and right ends of two busbars of the GIS device of the extra-high voltage substation and branch outgoing lines between each two circuit breakers respectively, arranging measuring points independently for each phase device, and the distance between the measuring points on the busbar and the device end is less than or equal to a first preset distance threshold, and the distance between the measuring points arranged between the circuit breakers and the outgoing line sleeve is less than or equal to the first preset distance threshold.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-voltage electrical equipment, and more particularly, to a GIS device internal transient arc online monitoring method and system. BACKGROUND

[0002] The ultra-high voltage GIS device is an important node device of the new power system backbone network, and its operation reliability is directly related to the safe and stable operation of the entire power system. In the field of pressure resistance and operation, insulation flashover faults may be caused due to manufacturing and installation defects, and then transient arcs are generated to stimulate complex transient voltage processes. In addition, during the operation of the circuit breaker and the disconnector of the GIS device, pre-breakdown and heavy breakdown may occur between the moving and static contacts to generate transient arcs and stimulate fast transient voltages. Through real-time monitoring of the transient arcs of the GIS device in the process of pressure resistance and operation, the insulation fault types inside the device can be judged, the arc position and even the secondary discharge position can be quickly located, and this is beneficial to timely troubleshooting. Through monitoring of the transient arcs of the circuit breaker and the disconnector during operation, the dynamic insulation characteristics between the moving and static contacts can be analyzed to serve as fingerprint characteristic quantities for electrical state evaluation. At present, the pressure resistance process of the ultra-high voltage GIS device mostly uses ultrasonic sensors to monitor internal insulation breakdown, but the ultrasonic method is easily disturbed by the outside world, is prone to misjudgment, has insufficient positioning accuracy, a large number of sensors need to be arranged on site, and it is difficult to identify the secondary discharge inside the GIS.

[0003] Therefore, there is a need for a GIS device internal transient arc online monitoring method and system. SUMMARY

[0004] The present application provides a GIS device internal transient arc online monitoring method and system to solve the problem of how to monitor the internal transient arcs of the ultra-high voltage full-station GIS device online.

[0005] In order to solve the above problems, according to one aspect of the present application, a GIS device internal transient arc online monitoring method is provided, which comprises:

[0006] arranging the internal sensor measuring points of the ultra-high voltage substation GIS device;

[0007] acquiring the transient voltages at each measuring point during the handover pressure resistance test and operation of the ultra-high voltage substation GIS device;

[0008] determining whether a ground breakdown transient arc occurs based on the transient voltages;

[0009] when it is determined that the ground breakdown transient arc occurs inside the ultra-high voltage substation GIS device, positioning the internal transient arc of the GIS device based on the transient voltages to determine the fault position;

[0010] The arrangement of the internal sensor measuring points of the GIS equipment of the extra-high voltage substation comprises:

[0011] The measuring points are arranged at the left and right ends of two busbars of the GIS equipment of the extra-high voltage substation and branch outgoing lines between each two circuit breakers, and the measuring points are independently arranged for each phase equipment, and the distance between the measuring points on the busbar and the end of the equipment is less than or equal to a first preset distance threshold, and the distance between the measuring points arranged between the circuit breakers and the outgoing line sleeve is less than or equal to the first preset distance threshold.

[0012] Preferably, a voltage sensor is arranged at each measuring point, and the voltage sensor is a hand hole type sensor based on capacitive voltage division.

[0013] Preferably, whether a ground breakdown transient arc occurs is determined based on the transient voltage, comprising:

[0014] For any phase of any measuring point, if the transient voltage falls from a positive peak to zero in the direction and the falling edge is less than or equal to a first preset time threshold and there is still induced voltage after the rising, or the transient voltage rises from a negative peak to zero in the direction and the rising edge is less than or equal to a first preset time threshold and there is still induced voltage after the rising, it is determined that a ground breakdown transient arc occurs.

[0015] Preferably, the GIS equipment internal transient arc positioning is performed based on the transient voltage to determine the fault location, comprising:

[0016] The measuring points at the two ends of the I busbar are set as No. 1 and No. 2, and the distance between the two measuring points is L1, the measuring points at the two ends of the II busbar are set as No. 1' and No. 2', and the distance between the two measuring points is L1'; the measuring points of each CB string connected with the I busbar and in the direction of No. 1 to No. 2 measuring points are set as No. 3, No. 4,..., No. n, and the measuring points of each CB string connected with the II busbar and in the direction of No. 1' to No. 2' measuring points are set as No. 3', No. 4',..., No. n', the distances between No. 3 to No. n measuring points and No. 1 measuring point are L 2-3 , L 2-4 ,..., L 2-n ; the distances between No. 3' to No. n' measuring points and No. 1' measuring point are L 2-3 ', L 2-4 ',..., L 2-n '; the distances from the physical space intersection points of each CB string and the I busbar to No. 2 measuring point are C3, C4,..., C n ; the distances from the physical space intersection points of each CB string and the II busbar to No. 2' measuring point are C3', C4',..., C n '; wherein, n-2 is the number of CB strings; all the above settings are for A, B, and C three phases;

[0017] In the handover pressure test and operation process, when it is determined that a transient arc occurs in the ground breakdown of any phase inside the GIS equipment of the extra-high voltage substation, at this time, the transient voltage is recorded at each measuring point of the any phase; the first positioning is performed by using the arrival time t1 and t2 of the measuring points 1 and 2 at both ends of the I bus, the arrival time t1' and t2' of the measuring points 1' and 2' at both ends of the II bus, and the distance L1 between the two measuring points at the I bus and the distance L1' between the two measuring points at the II bus, to determine the first distance P1 of the fault position from the measuring point 2 and the second distance P1' of the fault position from the measuring point 2'; if P1 is not equal to C3, C4,..., Cn, or P1' is not equal to C3', C4',..., Cn', it is determined that the fault position is on the I or II straight bus; if P1 is equal to C3, C4,..., Cn and the position P1' is equal to C3', C4',..., Cn', it is determined that the fault position is in the i-th CB string, 3≤i≤n. n n i i

[0018] When it is determined that the fault position is in the i-th CB string, the second positioning is performed, the measuring point … connected with the I bus in the i-th CB string is selected as the first target measuring point, the arrival time t3 of the transient voltage monitored by the first target measuring point is determined, the distance L2 between the first target measuring point and the measuring point 1 is determined, and the third distance P2 of the fault position from the first target measuring point is calculated; the measuring point ‘… connected with the II bus in the i-th CB string is selected as the second target measuring point, the arrival time t3' of the transient voltage monitored by the second target measuring point is determined, the distance L2' between the second target measuring point and the measuring point 1' is determined, and the fourth distance P2' of the fault position from the second target measuring point is calculated, and the fault position is determined according to the third distance P2 and the fourth distance P2'.

[0019] Preferably, the first distance is determined by using the following method, comprising:

[0020]

[0021] The second distance is determined by using the following method, comprising:

[0022]

[0023] The third distance is determined by using the following method, comprising:

[0024]

[0025] The fourth distance is determined by using the following method, comprising:

[0026] ​​​​​​​ ,

[0027] wherein c is the propagation speed of electromagnetic waves in the GIS.

[0028] Preferably, the method further comprises:

[0029] In the process of the handover withstand voltage test of the GIS equipment in the EHV substation, if the duration of the transient voltage excited by the arc to ground exceeds a second preset time threshold, and the falling edge or rising edge time is less than or equal to a third preset time threshold, it is determined that the fault type is surface breakdown of solid insulation; if the duration of the transient voltage excited by the arc to ground is less than or equal to a fourth preset time threshold, and the falling edge or rising edge time is less than or equal to a fifth preset time threshold, it is determined that the fault type is SF6 insulation gap breakdown.

[0030] In the process of the operation of the GIS equipment in the EHV substation, if the duration of the transient voltage excited by the arc to ground exceeds a sixth preset time threshold, and the falling edge or rising edge time is less than or equal to a seventh preset time threshold, it is determined that the fault type is surface breakdown of solid insulation; if the duration of the transient voltage excited by the arc to ground is less than or equal to the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, it is determined that the fault type is SF6 gas gap breakdown.

[0031] Preferably, the method further comprises:

[0032] The transient voltage at each measuring point is acquired by using a monitoring terminal connected with a voltage sensor at the measuring point; wherein the voltage sensor is connected with the monitoring terminal through an N-type cable transition head.

[0033] Preferably, the monitoring terminal comprises a sampling module, a synchronous time synchronization module, a synchronous time synchronization antenna, a power module and a deep isolation transformer, which are all installed in a shielding box made of stainless steel, and an external 220V AC power supply is provided; wherein the acquisition module adopts a steepness trigger mode, and when the monitoring waveform exceeds a set steepness, the acquisition card is triggered to record for a long time.

[0034] According to another aspect of the present application, there is provided a GIS internal transient arc online monitoring system, which comprises:

[0035] A voltage acquisition unit is configured to acquire the transient voltage at each measuring point in the process of the handover withstand voltage test and operation of the GIS equipment in the EHV substation.

[0036] A judgment unit is configured to determine whether the arc to ground breakdown transient occurs based on the transient voltage.

[0037] A fault position determination unit is configured to determine a fault position by locating a transient arc inside the GIS device based on the transient voltage when it is determined that a transient arc to ground occurs inside the GIS device of the extra-ultra high voltage substation.

[0038] wherein, the measuring points are arranged on the left and right ends of two busbars of the GIS device of the extra-ultra high voltage substation and branches of outgoing lines between each two circuit breakers, each phase device is independently arranged with measuring points, and the distance between the measuring points on the busbar and the end of the device is less than or equal to a first preset distance threshold, and the distance between the measuring points arranged between the circuit breakers and the outgoing line sleeve is less than or equal to the first preset distance threshold.

[0039] Preferably, wherein a voltage sensor based on capacitive voltage division is arranged at each measuring point.

[0040] Preferably, wherein the judging unit determines whether a transient arc to ground occurs based on the transient voltage, comprising:

[0041] For any phase of any measuring point, if the transient voltage falls from the positive peak value to zero in the direction and the falling edge is less than or equal to a first preset time threshold and there is still induced voltage after rising, or the transient voltage rises from the negative peak value to zero in the direction and the rising edge is less than or equal to a first preset time threshold and there is still induced voltage after rising, it is determined that a transient arc to ground occurs.

[0042] Preferably, wherein the fault position determination unit determines the fault position by locating the transient arc inside the GIS device based on the transient voltage, comprising:

[0043] Set the measuring points at the two ends of the I busbar as No. 1 and No. 2 respectively, and the distance between the two measuring points is L1, set the measuring points at the two ends of the II busbar as No. 1' and No. 2' respectively, and the distance between the two measuring points is L1'; set the measuring points of each CB string connected with the I busbar and along the direction of No. 1 to No. 2 measuring points as No. 3, No. 4,..., No. n respectively, set the measuring points of each CB string connected with the II busbar and along the direction of No. 1' to No. 2' measuring points as No. 3', No. 4',..., No. n' respectively, the distances between No. 3 to No. n measuring points and No. 1 measuring point are L 2-3 , L 2-4 ,..., L 2-n ; the distances between No. 3' to No. n' measuring points and No. 1' measuring point are L 2-3 ', L 2-4 ',..., L 2-n '; set the distances between the physical space intersection points of each CB string and the I busbar to No. 2 measuring point as C3, C4,..., C n ; the distances between the physical space intersection points of each CB string and the II busbar to No. 2' measuring point are C3', C4',..., Cn n-2 is the number of CB strings; all the above settings are A, B, C three-phase;

[0044] In the handover pressure test and operation process, when it is determined that the transient arc of the ground breakdown occurs in any phase of the GIS equipment of the extra-high voltage substation, at this time, the transient voltage is recorded at each measuring point of the any phase; the first positioning is performed by using the arrival time t1 and t2 of the measuring points 1 and 2 at both ends of the I bus, the arrival time t1' and t2' of the measuring points 1' and 2' at both ends of the II bus, the distance L1 between the two measuring points of the I bus and the distance L1' between the two measuring points of the II bus, to determine the first distance P1 of the fault position from the measuring point 2 and the second distance P1' of the fault position from the measuring point 2'; if P1 is not equal to C3, C4,..., C n , and the position P1' is not equal to C3', C4',..., C n , any one value, it is determined that the fault position is on the I or II straight bus; if P1 is equal to C i , and the position P1' is equal to C i , then it is determined that the fault position is in the i-th CB string, 3≤i≤n.

[0045] When it is determined that the fault position is in the i-th CB string, the second positioning is performed, the measuring point … connected with the I bus in the i-th CB string is selected as the first target measuring point, the arrival time t3 of the transient voltage monitored by the first target measuring point is determined, the distance L2 between the first target measuring point and the measuring point 1 is determined, and the third distance P2 of the fault position from the first target measuring point is calculated; the measuring point ‘… connected with the II bus in the i-th CB string is selected as the second target measuring point, the arrival time t3' of the transient voltage monitored by the second target measuring point is determined, the distance L2' between the second target measuring point and the measuring point 1' is determined, and the fourth distance P2' of the fault position from the second target measuring point is calculated, and the fault position is determined according to the third distance P2 and the fourth distance P2'.

[0046] Preferably, the fault position determination unit determines the first distance by using the following manner, comprising:

[0047] ,

[0048] determines the second distance by using the following manner, comprising:

[0049] ,

[0050] determines the third distance by using the following manner, comprising:

[0051] ,

[0052] The fourth distance is determined by the following method, comprising:

[0053] ,

[0054] Wherein, c is the propagation speed of electromagnetic wave in GIS.

[0055] Preferably, wherein the system further comprises: a fault type determination unit, configured to:

[0056] In the process of GIS equipment handover voltage withstand test of the ultra-high voltage substation, if the duration of transient voltage excited by the arc flash to ground exceeds a second preset time threshold, and the falling edge or rising edge time is less than or equal to a third preset time threshold, it is determined that the fault type is solid insulation surface breakdown; if the duration of transient voltage excited by the arc flash to ground is less than or equal to a fourth preset time threshold, and the falling edge or rising edge time is less than or equal to a fifth preset time threshold, it is determined that the fault type is SF6 insulation gap breakdown.

[0057] In the process of GIS equipment operation of the ultra-high voltage substation, if the duration of transient voltage excited by the arc flash to ground exceeds a sixth preset time threshold, and the falling edge or rising edge time is less than or equal to a seventh preset time threshold, it is determined that the fault type is solid insulation surface breakdown; if the duration of transient voltage excited by the arc flash to ground is less than or equal to a sixth preset time threshold, and the falling edge or rising edge time is less than or equal to a fifth preset time threshold, it is determined that the fault type is SF6 gas gap breakdown.

[0058] Preferably, wherein the system further comprises:

[0059] The monitoring terminal is connected with the voltage sensor at the measuring point, and is configured to acquire the transient voltage at each measuring point; wherein the voltage sensor is connected with the monitoring terminal through an N-type cable transition head.

[0060] Preferably, wherein the monitoring terminal comprises: a sampling module, a synchronous time synchronization module, a synchronous time synchronization antenna, a power module and a deep isolation transformer, all of which are installed in a shielding box made of stainless steel, and an external 220V AC power supply is provided; wherein the acquisition module adopts a steepness trigger mode, and when the monitoring waveform exceeds the set steepness, the acquisition card is triggered to record for a long time.

[0061] The application provides a GIS device internal transient arc online monitoring method and system, comprising: arranging a GIS device internal sensor measuring point of an extra-high voltage substation; obtaining transient voltages at each measuring point in a GIS device switching withstand voltage test and operation process of the extra-high voltage substation; determining whether a ground breakdown transient arc occurs based on the transient voltages; when it is determined that a ground breakdown transient arc occurs in the GIS device of the extra-high voltage substation, positioning the GIS device internal transient arc based on the transient voltages to determine a fault position; wherein the arranging the GIS device internal sensor measuring point of the extra-high voltage substation comprises: arranging measuring points on both ends of two busbars of the GIS device of the extra-high voltage substation and branch outgoing lines between each two circuit breakers, independently arranging measuring points for each phase device, and the distance between the measuring points on the busbar and the device end is less than or equal to a first preset distance threshold, and the distance between the measuring points arranged between the circuit breakers and the outgoing line sleeve is less than or equal to the first preset distance threshold. The application arranges built-in voltage sensors on the main busbar and the branch outgoing line, captures transient voltages to realize GIS internal transient arc online monitoring of the whole station in the field withstand voltage and operation, simultaneously utilizes the propagation time delay of the transient voltage, combines the distance between the measuring points, realizes accurate positioning of the arc, can judge the defect type of insulation breakdown, and improves the diagnosis accuracy. The GIS device internal transient arc online monitoring and positioning method of the whole station of the extra-high voltage proposed by the application realizes rapid judgment of the internal insulation fault type, accurate positioning of the arc position, is beneficial to timely troubleshooting, improves operation and maintenance efficiency, and has strong application demand. BRIEF DESCRIPTION OF DRAWINGS

[0062] The exemplary embodiments of the application can be more completely understood in reference to the following drawings:

[0063] Figure 1 A flowchart of the GIS device internal transient arc online monitoring method 100 according to the embodiment of the application;

[0064] Figure 2 A schematic diagram of the measuring point arrangement according to the embodiment of the application;

[0065] Figure 3 A connection diagram of the monitoring and positioning system according to the embodiment of the application;

[0066] Figure 4 A structural schematic diagram of the monitoring sensor unit according to the embodiment of the application;

[0067] Figure 5 A schematic diagram of the transient voltage excited by the GIS internal insulation ground breakdown transient arc according to the embodiment of the application;

[0068] Figure 6This is a schematic diagram of the structure of the GIS equipment internal transient electric arc online monitoring system 600 according to an embodiment of the present invention. Detailed Implementation

[0069] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0070] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0071] Figure 1 This is a flowchart of a method 200 for online monitoring of transient electric arcs inside GIS equipment according to an embodiment of the present invention. Figure 1 As shown, the online monitoring method for transient electric arcs inside GIS equipment provided by this invention involves arranging built-in voltage sensors on the main busbar and branch lines. During on-site withstand voltage testing and operation, it achieves online monitoring of transient electric arcs within the entire GIS substation by capturing transient voltages. Simultaneously, by utilizing the propagation delay of transient voltages and combining it with the distance between measuring points, it achieves accurate arc location and can also determine the type of insulation breakdown defect, improving diagnostic accuracy. The online monitoring and location method for transient electric arcs inside ultra-high voltage (UHV) substation GIS equipment proposed in this invention enables rapid identification of internal insulation fault types and accurate arc location, facilitating timely fault investigation and improving operation and maintenance efficiency, thus meeting strong application demands. The online monitoring method 100 for transient electric arcs inside GIS equipment provided by this invention begins at step 101, where the sensor measuring points inside the UHV substation GIS equipment are arranged.

[0072] The arrangement of sensor measuring points inside the GIS equipment of ultra-high voltage substations includes:

[0073] Measurement points are arranged at both ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Measurement points are arranged independently for each phase of the equipment. The distance between the measurement points on the busbars and the ends of the equipment is less than or equal to the first preset distance threshold. The distance between the measurement points arranged between the circuit breakers and the outgoing bushings is less than or equal to the first preset distance threshold.

[0074] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a handhole sensor based on capacitive voltage division.

[0075] In this invention, the first step is to arrange the built-in sensors throughout the substation. In ultra-high voltage substations, GIS equipment typically uses a three-way split connection, such as... Figure 2 As shown. To meet the requirements of transient arc monitoring within the GIS equipment across the entire station area, the location of the measuring points needs to be specially configured. First, measuring points are arranged at both ends of the two busbars, with each phase of the equipment requiring an independent measuring point, and the distance from the end of the equipment does not exceed the first preset distance threshold of 10 meters. Then, monitoring points also need to be configured on the branch lines between every two circuit breakers (CBs), and the distance from the monitoring points to the outgoing bushings does not exceed the first preset distance threshold of 10 meters.

[0076] In this invention, the built-in sensor is a capacitive voltage divider-based handhole sensor. A circular electrode with a radius not exceeding 150 mm and a thickness not exceeding 20 mm is integrated into the handhole on the GIS cylinder. The distance between the electrode and the inner edge of the GIS cylinder wall is not less than 5 mm. The circular electrode and the GIS conductor form a high-voltage arm capacitor. Between the electrode and the handhole cover, a polyimide film with a relative permittivity between 3.5 and 4.5 is used as the insulating medium to construct a low-voltage arm capacitor with an equivalent capacitance value not less than 5 nF.

[0077] In step 102, during the handover withstand voltage test and operation of the GIS equipment in the ultra-high voltage substation, the transient voltage at each measuring point is acquired.

[0078] Preferably, the method further includes:

[0079] The transient voltage at each measuring point is acquired using a monitoring terminal connected to a voltage sensor at the measuring point; the voltage sensor is connected to the monitoring terminal via an N-type cable adapter.

[0080] Preferably, the monitoring terminal includes: a sampling module, a synchronization time module, a synchronization time antenna, a power supply module, and a deep isolation transformer, all installed in a shielded box made of stainless steel, and provided with an external 220V AC power supply; wherein, the acquisition module adopts a steepness trigger mode, and when the monitored waveform exceeds the set steepness, it immediately triggers the acquisition card to record for a long time.

[0081] Combination Figure 3 and Figure 4As shown, in this invention, transient voltage is acquired through a monitoring terminal. The GIS equipment has a built-in sensor connected to an external monitoring terminal, which is directly connected to the voltage sensor via an N-type cable connector. The monitoring terminal includes a sampling module, a synchronization time module, a synchronization time antenna, a power supply module, and a deep isolation transformer, all housed in a stainless steel shielded enclosure, powered by an external 220V AC power supply. In this invention, the sampling module has a sampling rate of 200MS / s and a sampling analog bandwidth of 100MHz, supporting continuous acquisition and storage in FIFO mode. The acquisition module uses a steepness trigger mode; once the monitored waveform exceeds a set steepness, it immediately triggers long-term recording on the acquisition card. The time accuracy of the synchronization module is no less than 15ns. The local power supply module draws power from a nearby 220V power source at the GIS site, with a power output of no less than 30W. The upper-level storage and control unit includes an optical switch, a control host (server), a display, and a keyboard, and can be placed in a cabinet in the substation's relay protection room. The monitoring terminal is connected to the optical switch via a single-mode optical fiber.

[0082] In step 103, it is determined whether a transient arc to ground has occurred based on the transient voltage.

[0083] Preferably, determining whether a transient arc to ground breakdown has occurred based on the transient voltage includes:

[0084] For any phase at any measurement point, if the transient voltage drops from the positive peak to zero and the falling edge is less than or equal to the first preset time threshold and there is still an induced voltage after the rise, or if the transient voltage rises from the negative peak to zero and the rising edge is less than or equal to the first preset time threshold and there is still an induced voltage after the rise, then it is determined that a transient arc to ground breakdown has occurred.

[0085] During the handover withstand voltage test and operation, when a transient arc causing ground fault occurs inside the GIS equipment of an ultra-high voltage substation, the resulting transient voltage process is as follows: Figure 5 As shown. When the device voltage drops from a positive peak to zero with a falling edge of less than 200ns, or rises from a negative peak to zero with a rising edge of less than 200ns, and there is still a certain induced voltage afterward, it is determined that a transient arc to ground breakdown has occurred inside the GIS.

[0086] Therefore, in this invention, the first preset time threshold can be set to 200 ns. When determining the transient arc of ground breakdown caused by insulation breakdown inside GIS equipment, for any phase, if the transient voltage drops from a positive peak value to zero with a falling edge less than or equal to the first preset time threshold and an induced voltage still exists after the voltage rises, or if the transient voltage rises from a negative peak value to zero with a rising edge less than or equal to the first preset time threshold and an induced voltage still exists after the voltage rises, then a transient arc of ground breakdown is determined to have occurred.

[0087] In step 104, when it is determined that a transient arc breaking down to ground occurs inside the GIS equipment of the ultra-high voltage substation, the transient arc inside the GIS equipment is located based on the transient voltage to determine the fault location.

[0088] Preferably, the method for locating transient electric arcs inside the GIS equipment based on the transient voltage to determine the fault location includes:

[0089] Set the measuring points at both ends of bus I to be 1 and 2, with a distance of L1 between them. Set the measuring points at both ends of bus II to be 1' and 2', with a distance of L1' between them. Set the measuring points of each CB string connected to bus I and along the direction from measuring point 1 to measuring point 2 to be 3, 4, ..., n. Set the measuring points of each CB string connected to bus II and along the direction from measuring point 1' to measuring point 2' to be 3', 4', ..., n', with a distance of L1' between measuring points 3 to n and measuring point 1. 2-3 L 2-4 、......、L 2-n The distances between measuring points 3' to n' and measuring point 1' are respectively L 2-3 '、L 2-4 '、......、L 2-n '; Set the distance from the physical intersection point of each CB string and the I bus to measurement point 2 as C3, C4, ..., C n The distances from the physical intersection points of each CB string and the II busbar to measuring point 2' are C3', C4', ..., C... n '; where n-2 is the number of CB strings; all the above settings are three phases: A, B, and C;

[0090] During the handover withstand voltage test and operation, when a transient arc causing a ground fault occurs in any phase of the GIS equipment in the ultra-high voltage substation, transient voltages are recorded at each measuring point of that phase. Using the arrival times t1 and t2 of measuring points 1 and 2 at both ends of bus I of that phase, and the arrival times t1' and t2' of measuring points 1' and 2' at both ends of bus II, as well as the distances L1 between the two measuring points on bus I and L1' between the two measuring points on bus II, initial location is determined. The first distance P1 from measuring point 2 and the second distance P1' from measuring point 2' are then determined. If P1 is not equal to C3, C4, ..., C... n Which value or position P1' is not equal to C3', C4', ..., C? n 'If any value is specified, the fault location is determined to be on busbar I or II; if P1 equals C...' i And position P1' equals C iIf ', then the fault location is determined to be within the i-th CB string, where 3≤i≤n;

[0091] When the fault location is determined to be within the i-th CB string, a secondary positioning is performed. The measurement point connected to the I bus in the i-th CB string is selected as the first target measurement point. The arrival time t3 of the transient voltage monitored by the first target measurement point is determined, as well as the distance L2 between the first target measurement point and measurement point 1. The third distance P2 between the fault location and the first target measurement point is calculated. The measurement point '...' connected to the II bus in the i-th CB string is selected as the second target measurement point. The arrival time t3' of the transient voltage monitored by the second target measurement point is determined, as well as the distance L2' between the second target measurement point and measurement point 1'. The fourth distance P2' between the fault location and the second target measurement point is calculated. The fault location is determined based on the third distance P2 and the fourth distance P2'.

[0092] Preferably, the first distance is determined using the following method:

[0093] ,

[0094] The second distance is determined using the following methods:

[0095] ,

[0096] The third distance is determined using the following methods:

[0097] ,

[0098] The fourth distance is determined using the following methods:

[0099] ,

[0100] Where c is the propagation speed of electromagnetic waves within the GIS.

[0101] In this invention, fault location can also be performed. First, according to the substation GIS design drawings, the measuring points at both ends of bus I are set as No. 1 and No. 2, and the distance between the two measuring points is L1. The measuring points at both ends of bus II are set as No. 1' and No. 2', and the distance between the two measuring points is L1'. The measuring points of each CB string connected to bus I and along the direction from measuring point 1 to No. 2 are set as No. 3, No. 4, ..., No. n. The measuring points of each CB string connected to bus II and along the direction from measuring point 1' to No. 2' are set as No. 3', No. 4', ..., No. n'. The distances between measuring points 3 to n and measuring point 1 are L1', L1', L2 ... 2-3 L 2-4 、......、L 2-n The distances between measuring points 3' to n' and measuring point 1' are respectively L2-3 '、L 2-4 '、......、L 2-n '; Set the distance from the physical intersection point of each CB string and the I bus to measurement point 2 as C3, C4, ..., C n The distances from the physical intersection points of each CB string and the II busbar to measuring point 2' are C3', C4', ..., C... n '; where n-2 is the number of CB strings; all the above settings are for three phases A, B, and C; during the handover withstand voltage test and operation, when it is determined that a transient arc of ground breakdown occurs inside any phase of the GIS equipment of the ultra-high voltage substation, the transient voltage is recorded at each measuring point of that phase; using the arrival times t1 and t2 of the measuring points at both ends of bus I of that phase, i.e., points 1 and 2, and the arrival times t1' and t2' of the measuring points at both ends of bus II, i.e., points 1' and 2', as well as the distance L1 between the two measuring points of bus I and the distance L1' between the two measuring points of bus II, the first location is determined, and the first distance P1 of the fault location from measuring point 2 and the second distance P1' of the fault location from measuring point 2' are determined; if P1 is not equal to C3, C4, ..., C n Which value or position P1' is not equal to C3', C4', ..., C? n 'If any value is specified, the fault location is determined to be on busbar I or II; if P1 equals C...' i And position P1' equals C i If the fault location is determined to be within the i-th CB string, 3≤i≤n; when the fault location is determined to be within the i-th CB string, a secondary positioning is performed. The measurement point connected to the I bus in the i-th CB string is selected as the first target measurement point. The arrival time t3 of the transient voltage monitored by the first target measurement point is determined, as well as the distance L2 between the first target measurement point and measurement point 1. The third distance P2 between the fault location and the first target measurement point is calculated. The measurement point '...' connected to the II bus in the i-th CB string is selected as the second target measurement point. The arrival time t3' of the transient voltage monitored by the second target measurement point is determined, as well as the distance L2' between the second target measurement point and measurement point 1'. The fourth distance P2' between the fault location and the second target measurement point is calculated. The fault location is determined based on the third distance P2 and the fourth distance P2'.

[0102] The first distance is determined using the following methods:

[0103] ,

[0104] The second distance is determined using the following methods:

[0105] ,

[0106] The third distance is determined using the following methods:

[0107] ,

[0108] The fourth distance is determined using the following methods:

[0109] ,

[0110] Where c is the propagation speed of electromagnetic waves in GIS, which is generally taken as 292 m / us.

[0111] Preferably, the method further includes:

[0112] During the handover withstand voltage test of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the second preset time threshold, and the falling edge or rising edge time is less than or equal to the third preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the fourth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 insulation gap breakdown.

[0113] During the operation of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 gas gap breakdown.

[0114] In this invention, combined with Figure 5As shown, during the withstand voltage test of ultra-high voltage GIS equipment, if the duration of the transient voltage generated by the flashover arc to ground exceeds the first preset time threshold of 1 ms, and the falling edge or rising edge time is less than or equal to the third preset time threshold of 150 ns, the fault type is surface breakdown of solid insulation components; if the duration of the transient voltage generated by the flashover arc to ground is less than or equal to the fourth preset time threshold of 500 μs, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold of 130 ns, the fault type is SF6 gas gap breakdown. During the operation of ultra-high voltage GIS equipment, if the duration of the transient voltage generated by the flashover arc to ground exceeds the sixth preset time threshold of 100 μs, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold of 900 ns, the fault type is surface breakdown of solid insulation components; if the duration of the transient voltage generated by the flashover arc to ground is less than or equal to the sixth preset time threshold of 100 μs, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold of 130 ns, the fault type is SF6 gas gap breakdown.

[0115] Compared to existing traditional ultrasonic methods, the number of sensors required in this invention is significantly reduced. Since the sensors are built into GIS equipment, they have excellent anti-interference capabilities. Furthermore, no additional sensors need to be deployed during the pressure test, and monitoring functions can be implemented during operation, thus overcoming the shortcomings of traditional ultrasonic methods.

[0116] During on-site withstand voltage testing and operation, online monitoring of transient arcs within the entire GIS (Gas Insulation System) is achieved by capturing transient voltages. Simultaneously, by utilizing the propagation delay of transient voltages and combining it with the distance between measuring points, the location of the arc and even secondary discharge can be quickly pinpointed, facilitating timely fault diagnosis. By utilizing the time-domain variation characteristics of transient voltages, accurate identification of arcs within the GIS can be achieved, effectively eliminating external interference. Furthermore, the type of insulation breakdown defect can be determined, improving diagnostic accuracy.

[0117] Monitoring transient arcs during operation of circuit breakers and disconnectors in GIS equipment can be used to analyze the dynamic insulation characteristics between moving and stationary contacts, serving as a fingerprint feature for electrical condition assessment.

[0118] The proposed method for online monitoring of transient electric arcs inside ultra-high voltage and extra-high voltage GIS equipment can quickly determine the type of internal insulation fault and accurately locate the arc, which is conducive to timely fault diagnosis. It can also realize the electrical condition assessment of circuit breakers and disconnectors in GIS equipment, improve the efficiency of operation and maintenance, and has strong application demand.

[0119] Figure 6 This is a schematic diagram of the structure of a transient electric arc online monitoring system 600 inside a GIS device according to an embodiment of the present invention. Figure 6As shown, the GIS equipment internal transient electric arc online monitoring system 600 provided by the embodiment of the present invention includes: a voltage acquisition unit 601, a judgment unit 602, and a fault location determination unit 603.

[0120] Preferably, the voltage acquisition unit 601 is used to acquire transient voltages at various measuring points during the handover withstand voltage test and operation of GIS equipment in ultra-high voltage substations.

[0121] Among them, measuring points are arranged at both ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Each phase of the equipment is independently equipped with measuring points, and the distance between the measuring points on the busbars and the ends of the equipment is less than or equal to the first preset distance threshold. The distance between the measuring points arranged between the circuit breakers and the outgoing bushings is less than or equal to the first preset distance threshold.

[0122] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a handhole sensor based on capacitive voltage division.

[0123] Preferably, the judgment unit 602 is used to determine whether a transient arc to ground has occurred based on the transient voltage.

[0124] Preferably, the determination unit 602, based on the transient voltage, determines whether a transient arc to ground breakdown has occurred, including:

[0125] For any phase at any measurement point, if the transient voltage drops from the positive peak to zero and the falling edge is less than or equal to the first preset time threshold and there is still an induced voltage after the rise, or if the transient voltage rises from the negative peak to zero and the rising edge is less than or equal to the first preset time threshold and there is still an induced voltage after the rise, then it is determined that a transient arc to ground breakdown has occurred.

[0126] Preferably, the fault location determination unit 603 is used to locate the transient arc inside the GIS equipment based on the transient voltage when it is determined that a transient arc of ground breakdown has occurred inside the GIS equipment of the ultra-high voltage substation.

[0127] Preferably, the fault location determination unit 603 determines the fault location based on the transient voltage by performing transient arc location inside the GIS equipment, including:

[0128] Set the measuring points at both ends of bus I to be 1 and 2, with a distance of L1 between them. Set the measuring points at both ends of bus II to be 1' and 2', with a distance of L1' between them. Set the measuring points of each CB string connected to bus I and along the direction from measuring point 1 to measuring point 2 to be 3, 4, ..., n. Set the measuring points of each CB string connected to bus II and along the direction from measuring point 1' to measuring point 2' to be 3', 4', ..., n', with a distance of L1' between measuring points 3 to n and measuring point 1. 2-3 L 2-4 、......、L 2-n The distances between measuring points 3' to n' and measuring point 1' are respectively L 2-3 '、L 2-4 '、......、L 2-n '; Set the distance from the physical intersection point of each CB string and the I bus to measurement point 2 as C3, C4, ..., C n The distances from the physical intersection points of each CB string and the II busbar to measuring point 2' are C3', C4', ..., C... n '; where n-2 is the number of CB strings; all the above settings are three phases: A, B, and C;

[0129] During the handover withstand voltage test and operation, when a transient arc causing a ground fault occurs in any phase of the GIS equipment in the ultra-high voltage substation, transient voltages are recorded at each measuring point of that phase. Using the arrival times t1 and t2 of measuring points 1 and 2 at both ends of bus I of that phase, and the arrival times t1' and t2' of measuring points 1' and 2' at both ends of bus II, as well as the distances L1 between the two measuring points on bus I and L1' between the two measuring points on bus II, initial location is determined. The first distance P1 from measuring point 2 and the second distance P1' from measuring point 2' are then determined. If P1 is not equal to C3, C4, ..., C... n Which value or position P1' is not equal to C3', C4', ..., C? n 'If any value is specified, the fault location is determined to be on busbar I or II; if P1 equals C...' i And position P1' equals C i If ', then the fault location is determined to be within the i-th CB string, where 3≤i≤n;

[0130] When the fault location is determined to be within the i-th CB string, a secondary positioning is performed. The measurement point connected to the I bus in the i-th CB string is selected as the first target measurement point. The arrival time t3 of the transient voltage monitored by the first target measurement point is determined, as well as the distance L2 between the first target measurement point and measurement point 1. The third distance P2 between the fault location and the first target measurement point is calculated. The measurement point '...' connected to the II bus in the i-th CB string is selected as the second target measurement point. The arrival time t3' of the transient voltage monitored by the second target measurement point is determined, as well as the distance L2' between the second target measurement point and measurement point 1'. The fourth distance P2' between the fault location and the second target measurement point is calculated. The fault location is determined based on the third distance P2 and the fourth distance P2'.

[0131] Preferably, the fault location determination unit 603 determines the first distance using the following method:

[0132] ,

[0133] The second distance is determined using the following methods:

[0134] ,

[0135] The third distance is determined using the following methods:

[0136] ,

[0137] The fourth distance is determined using the following methods:

[0138] ,

[0139] Where c is the propagation speed of electromagnetic waves within the GIS.

[0140] Preferably, the system further includes: a fault type determination unit, used for:

[0141] During the handover withstand voltage test of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the second preset time threshold, and the falling edge or rising edge time is less than or equal to the third preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the fourth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 insulation gap breakdown.

[0142] During the operation of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 gas gap breakdown.

[0143] Preferably, the system further includes:

[0144] The monitoring terminal is connected to the voltage sensor at the measuring point to acquire the transient voltage at each measuring point; the voltage sensor is connected to the monitoring terminal through an N-type cable adapter.

[0145] Preferably, the monitoring terminal includes: a sampling module, a synchronization time module, a synchronization time antenna, a power supply module, and a deep isolation transformer, all installed in a shielded box made of stainless steel, and provided with an external 220V AC power supply; wherein, the acquisition module adopts a steepness trigger mode, and when the monitored waveform exceeds the set steepness, it immediately triggers the acquisition card to record for a long time.

[0146] The GIS equipment internal transient electric arc online monitoring system 600 of this embodiment corresponds to the GIS equipment internal transient electric arc online monitoring method 100 of another embodiment of this invention, and will not be described again here.

[0147] The present invention has been described with reference to a few embodiments. However, it will be apparent to those skilled in the art that other embodiments besides those disclosed above fall equivalently within the scope of the present invention.

[0148] Generally, all terms used in this invention are interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0149] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0150] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0151] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0152] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for online monitoring of transient electric arcs inside GIS equipment, characterized in that, The method includes: Arrangement of sensor measuring points inside the GIS equipment of ultra-high voltage and extra-high voltage substations; During the handover withstand voltage test and operation of GIS equipment in ultra-high voltage substations, transient voltages at various measuring points are acquired. Determine whether a transient arc to ground breakdown has occurred based on the transient voltage; When it is determined that a transient arc to ground occurs inside the GIS equipment of an ultra-high voltage substation, the transient arc inside the GIS equipment is located based on the transient voltage to determine the fault location. The arrangement of sensor measuring points inside the GIS equipment of ultra-high voltage substations includes: Measurement points are arranged at both ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Measurement points are arranged independently for each phase of the equipment. The distance between the measurement points on the busbars and the end of the equipment is less than or equal to the first preset distance threshold. The distance between the measurement points arranged between the circuit breakers and the outgoing bushings is less than or equal to the first preset distance threshold. The step of determining whether a transient arc to ground breakdown has occurred based on the transient voltage includes: For any phase at any measurement point, if the transient voltage drops from the positive peak to zero and the falling edge is less than or equal to the first preset time threshold and there is still an induced voltage after it rises, or if the transient voltage rises from the negative peak to zero and the rising edge is less than or equal to the first preset time threshold and there is still an induced voltage after it rises, then it is determined that a transient arc to ground breakdown has occurred. In the handover withstand voltage test of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the second preset time threshold, and the falling edge or rising edge time is less than or equal to the third preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the fourth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 insulation gap breakdown. During the operation of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 gas gap breakdown.

2. The method according to claim 1, characterized in that, A voltage sensor is installed at each measuring point. The voltage sensor is a hand-hole sensor based on capacitive voltage division.

3. The method according to claim 1, characterized in that, Based on the transient voltage, the transient arc location inside the GIS equipment is determined to locate the fault, including: Set the measuring points at both ends of bus I to be 1 and 2, with a distance of L1 between them. Set the measuring points at both ends of bus II to be 1' and 2', with a distance of L1' between them. Set the measuring points of each CB string connected to bus I and along the direction from measuring point 1 to measuring point 2 to be 3, 4, ..., n. Set the measuring points of each CB string connected to bus II and along the direction from measuring point 1' to measuring point 2' to be 3', 4', ..., n', with a distance of L1' between measuring points 3 to n and measuring point 1. 2-3 L 2-4 、......、L 2-n The distances between measuring points 3' to n' and measuring point 1' are respectively L 2-3 '、L 2-4 '、......、L 2-n '; Set the distance from the physical intersection point of each CB string and the I bus to measurement point 2 as C3, C4, ..., C n The distances from the physical intersection points of each CB string and the II busbar to measuring point 2' are C3', C4', ..., C... n '; where n-2 is the number of CB strings; all the above settings are three phases: A, B, and C; During the handover withstand voltage test and operation, when a transient arc causing a ground fault occurs in any phase of the GIS equipment in the ultra-high voltage substation, transient voltages are recorded at each measuring point of that phase. Using the arrival times t1 and t2 of measuring points 1 and 2 at both ends of bus I of that phase, and the arrival times t1' and t2' of measuring points 1' and 2' at both ends of bus II, as well as the distances L1 between the two measuring points on bus I and L1' between the two measuring points on bus II, initial location is determined. The first distance P1 from measuring point 2 and the second distance P1' from measuring point 2' are then determined. If P1 is not equal to C3, C4, ..., C... n Which value or position P1' is not equal to C3', C4', ..., C? n 'If any value is specified, the fault location is determined to be on busbar I or II; if P1 equals C...' i And position P1' equals C i If ', then the fault location is determined to be within the i-th CB string, where 3≤i≤n; When the fault location is determined to be within the i-th CB string, a secondary positioning is performed. The measurement point connected to the I bus in the i-th CB string is selected as the first target measurement point. The arrival time t3 of the transient voltage monitored by the first target measurement point is determined, as well as the distance L2 between the first target measurement point and measurement point 1. The third distance P2 between the fault location and the first target measurement point is calculated. The measurement point '...' connected to the II bus in the i-th CB string is selected as the second target measurement point. The arrival time t3' of the transient voltage monitored by the second target measurement point is determined, as well as the distance L2' between the second target measurement point and measurement point 1'. The fourth distance P2' between the fault location and the second target measurement point is calculated. The fault location is determined based on the third distance P2 and the fourth distance P2'.

4. The method according to claim 3, characterized in that, The first distance is determined using the following methods: The second distance is determined using the following methods: The third distance is determined using the following methods: The fourth distance is determined using the following methods: Where c is the propagation speed of electromagnetic waves within the GIS.

5. The method according to claim 1, characterized in that, The method further includes: The transient voltage at each measuring point is acquired using a monitoring terminal connected to a voltage sensor at the measuring point; the voltage sensor is connected to the monitoring terminal via an N-type cable adapter.

6. The method according to claim 5, characterized in that, The monitoring terminal includes a sampling module, a synchronization time module, a synchronization time antenna, a power supply module, and a deep isolation transformer, all installed in a shielded box made of stainless steel, and provided with an external 220V AC power supply; wherein, the sampling module adopts a steepness trigger mode, and when the monitored waveform exceeds the set steepness, it immediately triggers the acquisition card to record for a long time.

7. A transient electric arc online monitoring system inside a GIS device, characterized in that, The system includes: The voltage acquisition unit is used to acquire transient voltages at various measuring points during the handover withstand voltage test and operation of GIS equipment in ultra-high voltage and extra-high voltage substations. The judgment unit is used to determine whether a transient arc to ground breakdown has occurred based on the transient voltage; The fault location determination unit is used to locate the transient arc inside the GIS equipment based on the transient voltage when it is determined that a transient arc of ground breakdown has occurred inside the GIS equipment of the ultra-high voltage substation; Among them, measuring points are arranged at both ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch line between every two circuit breakers. Each phase equipment is independently equipped with measuring points, and the distance between the measuring points on the busbar and the end of the equipment is less than or equal to the first preset distance threshold. The distance between the measuring points arranged between the circuit breakers and the outgoing bushing is less than or equal to the first preset distance threshold. The determination unit, based on the transient voltage, determines whether a transient arc to ground has occurred, including: For any phase at any measurement point, if the transient voltage drops from the positive peak to zero and the falling edge is less than or equal to the first preset time threshold and there is still an induced voltage after it rises, or if the transient voltage rises from the negative peak to zero and the rising edge is less than or equal to the first preset time threshold and there is still an induced voltage after it rises, then it is determined that a transient arc to ground breakdown has occurred. Fault type determination unit, used for: During the handover withstand voltage test of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the second preset time threshold, and the falling edge or rising edge time is less than or equal to the third preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the fourth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 insulation gap breakdown. During the operation of GIS equipment in ultra-high voltage substations, if the duration of the transient voltage generated by the ground flashover arc exceeds the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold, the fault type is determined to be surface breakdown of solid insulation components; if the duration of the transient voltage generated by the ground flashover arc is less than or equal to the sixth preset time threshold, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold, the fault type is determined to be SF6 gas gap breakdown.

8. The system according to claim 7, characterized in that, A voltage sensor is installed at each measuring point. The voltage sensor is a hand-hole sensor based on capacitive voltage division.

9. The system according to claim 7, characterized in that, The fault location determination unit determines the fault location based on the transient voltage by locating the transient electric arc inside the GIS equipment, including: Set the measuring points at both ends of bus I to be 1 and 2, with a distance of L1 between them. Set the measuring points at both ends of bus II to be 1' and 2', with a distance of L1' between them. Set the measuring points of each CB string connected to bus I and along the direction from measuring point 1 to measuring point 2 to be 3, 4, ..., n. Set the measuring points of each CB string connected to bus II and along the direction from measuring point 1' to measuring point 2' to be 3', 4', ..., n', with a distance of L1' between measuring points 3 to n and measuring point 1. 2-3 L 2-4 、......、L 2-n The distances between measuring points 3' to n' and measuring point 1' are respectively L 2-3 '、L 2-4 '、......、L 2-n '; Set the distance from the physical intersection point of each CB string and the I bus to measurement point 2 as C3, C4, ..., C n The distances from the physical intersection points of each CB string and the II busbar to measuring point 2' are C3', C4', ..., C... n '; where n-2 is the number of CB strings; all the above settings are three phases: A, B, and C; During the handover withstand voltage test and operation, when a transient arc causing a ground fault occurs in any phase of the GIS equipment in the ultra-high voltage substation, transient voltages are recorded at each measuring point of that phase. Using the arrival times t1 and t2 of measuring points 1 and 2 at both ends of bus I of that phase, and the arrival times t1' and t2' of measuring points 1' and 2' at both ends of bus II, as well as the distances L1 between the two measuring points on bus I and L1' between the two measuring points on bus II, initial location is determined. The first distance P1 from measuring point 2 and the second distance P1' from measuring point 2' are then determined. If P1 is not equal to C3, C4, ..., C... n Which value or position P1' is not equal to C3', C4', ..., C? n 'If any value is specified, the fault location is determined to be on busbar I or II; if P1 equals C...' i And position P1' equals C i If ', then the fault location is determined to be within the i-th CB string, where 3≤i≤n; When the fault location is determined to be within the i-th CB string, a secondary positioning is performed. The measurement point connected to the I bus in the i-th CB string is selected as the first target measurement point. The arrival time t3 of the transient voltage monitored by the first target measurement point is determined, as well as the distance L2 between the first target measurement point and measurement point 1. The third distance P2 between the fault location and the first target measurement point is calculated. The measurement point '...' connected to the II bus in the i-th CB string is selected as the second target measurement point. The arrival time t3' of the transient voltage monitored by the second target measurement point is determined, as well as the distance L2' between the second target measurement point and measurement point 1'. The fourth distance P2' between the fault location and the second target measurement point is calculated. The fault location is determined based on the third distance P2 and the fourth distance P2'.

10. The system according to claim 9, characterized in that, The fault location determination unit determines the first distance using the following methods: The second distance is determined using the following methods: The third distance is determined using the following methods: The fourth distance is determined using the following methods: Where c is the propagation speed of electromagnetic waves within the GIS.

11. The system according to claim 7, characterized in that, The system also includes: The monitoring terminal is connected to the voltage sensor at the measuring point to acquire the transient voltage at each measuring point; the voltage sensor is connected to the monitoring terminal through an N-type cable adapter.

12. The system according to claim 11, characterized in that, The monitoring terminal includes a sampling module, a synchronization time module, a synchronization time antenna, a power supply module, and a deep isolation transformer, all installed in a shielded box made of stainless steel, and provided with an external 220V AC power supply; wherein, the sampling module adopts a steepness trigger mode, and when the monitored waveform exceeds the set steepness, it immediately triggers the acquisition card to record for a long time.

Images