GIS equipment internal transient arc on-line monitoring method and system

Abstract

The invention discloses a GIS equipment internal transient arc online monitoring method and system. The method comprises the following steps: arranging internal sensor measuring points of GIS equipment of an ultra-high voltage transformer substation; acquiring transient voltage at each measuring point in the process of switching over the withstand voltage test and the operation process; determining whether a breakdown-to-ground transient arc occurs based on the transient voltage; when it is determined that the transient arc which breaks down to the ground occurs, positioning the transient arc in the GIS equipment based on the transient voltage, and determining a fault position; wherein the arrangement of the internal sensor measuring points of the GIS equipment of the extra-high voltage transformer substation comprises the following steps: respectively arranging the measuring points at the left and right ends of two buses of the GIS equipment of the extra-high voltage transformer substation and on branch outgoing lines between every two circuit breakers, and independently arranging the measuring points on each phase of equipment, the distance between the measuring point on the bus and the end part of the equipment is smaller than or equal to a first preset distance threshold value, and the distance between the measuring point arranged between the circuit breakers and the outgoing line sleeve is smaller than or equal to the first preset distance threshold value.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage electrical equipment, and more specifically, to an online monitoring method and system for transient arcs inside GIS equipment. Background Art

[0002] Ultra-high voltage GIS equipment is an important node equipment of the backbone grid of the new power system. Its operation reliability is directly related to the safe and stable operation of the entire power system. During the withstand voltage test and operation, insulation flashover failure may be caused by manufacturing and installation defects, which will generate transient arcs and stimulate complex transient voltage processes. In addition, during the operation of the circuit breaker and disconnector of the GIS equipment, pre-breakdown and re-breakdown will occur between the moving and static contacts, generating transient arcs and stimulating ultra-fast transient voltages. Real-time monitoring of transient arcs of GIS equipment during withstand voltage test and operation can be used to determine the type of insulation fault inside the equipment, quickly locate the arc position and even the secondary discharge position, which is conducive to timely troubleshooting. By monitoring the transient arcs of circuit breakers and disconnectors during operation, it can be used to analyze the dynamic insulation characteristics between the moving and static contacts as a fingerprint feature for electrical status evaluation. At present, ultrasonic sensors are mostly used to monitor internal insulation breakdown during the withstand voltage test of ultra-high voltage GIS equipment, but the ultrasonic method is easily affected by external interference, which is easy to cause misjudgment, and the positioning accuracy is insufficient. A large number of sensors need to be deployed on site, and it is difficult to identify the secondary discharge inside the GIS.

[0003] Therefore, a method and system for online monitoring of transient arcs inside GIS equipment is needed. Summary of the invention

[0004] The present invention proposes an online monitoring method and system for transient arcs inside GIS equipment to solve the problem of how to perform online monitoring of transient arcs inside ultra-high voltage full-station GIS equipment.

[0005] In order to solve the above problem, according to one aspect of the present invention, a method for online monitoring of transient arcs in GIS equipment is provided, the method comprising: Arrangement of sensor measurement points inside the UHV substation GIS equipment; During the handover withstand voltage test and operation of GIS equipment in UHV substations, the transient voltage at each measuring point is obtained; determining whether a transient arc to ground breakdown occurs based on the transient voltage; When it is determined that a transient arc to ground breakdown 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; The arrangement of sensor measuring points inside the UHV substation GIS equipment includes: Measuring points are arranged on the left and right ends of the two busbars of the GIS equipment of the ultra-high voltage substation and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

[0006] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a hand-hole type sensor based on capacitive voltage division.

[0007] Preferably, determining whether a transient arc to ground breakdown occurs based on the transient voltage comprises: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

[0008] Preferably, the method of locating the transient arc inside the GIS equipment based on the transient voltage to determine the fault location includes: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ', L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

[0009] Preferably, the first distance is determined in the following manner, including: , The second distance is determined by: , The third distance is determined by: , The fourth distance is determined by: , Where c is the propagation speed of electromagnetic waves in GIS.

[0010] Preferably, the method further comprises: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

[0011] Preferably, the method further comprises: The transient voltage at each measuring point is obtained by using a monitoring terminal connected to a voltage sensor at the measuring point; wherein the voltage sensor is connected to the monitoring terminal via an N-type cable transition connector.

[0012] Preferably, the monitoring terminal includes: a sampling module, a synchronization module, a synchronization antenna, a power supply 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, it immediately triggers the acquisition card for long-term recording.

[0013] According to another aspect of the present invention, a system for online monitoring of transient arcs in GIS equipment is provided, the system comprising: The voltage acquisition unit is used to obtain the transient voltage at each measuring point during the handover withstand voltage test and operation of the GIS equipment in the UHV substation; A judgment unit, used for determining whether a transient arc to ground breakdown occurs based on the transient voltage; A fault location determination unit, for locating the transient arc inside the GIS equipment based on the transient voltage to determine the fault location when it is determined that a transient arc to ground breakdown occurs inside the GIS equipment of the ultra-high voltage substation; Among them, measuring points are arranged on the left and right ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

[0014] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a hand-hole type sensor based on capacitive voltage division.

[0015] Preferably, the judging unit determines whether a transient arc to ground breakdown occurs based on the transient voltage, comprising: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

[0016] Preferably, the fault location determination unit locates the transient arc inside the GIS equipment based on the transient voltage to determine the fault location, including: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ', L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

[0017] Preferably, the fault location determining unit determines the first distance in the following manner, including: , The second distance is determined by: , The third distance is determined by: , The fourth distance is determined by: , Where c is the propagation speed of electromagnetic waves in GIS.

[0018] Preferably, the system further comprises: a fault type determination unit, configured to: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

[0019] Preferably, the system further comprises: The monitoring terminal is connected to the voltage sensor at the measuring point and is used to obtain the transient voltage at each measuring point; wherein the voltage sensor is connected to the monitoring terminal through an N-type cable transition connector.

[0020] Preferably, the monitoring terminal includes: a sampling module, a synchronization module, a synchronization antenna, a power supply 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, it immediately triggers the acquisition card for long-term recording.

[0021] The present invention provides a method and system for online monitoring of transient arcs inside GIS equipment, comprising: arranging sensor measuring points inside GIS equipment of an ultra-ultra-high voltage substation; obtaining transient voltages at various measuring points during the handover withstand voltage test and operation of the GIS equipment of the ultra-ultra-high voltage substation; determining whether a transient arc to ground breakdown occurs based on the transient voltage; when it is determined that a transient arc to ground breakdown occurs inside the GIS equipment of the ultra-ultra-high voltage substation, locating the transient arc inside the GIS equipment based on the transient voltage to determine the fault location; wherein, arranging sensor measuring points inside the GIS equipment of the ultra-ultra-high voltage substation comprises: arranging measuring points at the left and right ends of two busbars of the GIS equipment of the ultra-ultra-high voltage substation and on the branch lines between every two circuit breakers, arranging measuring points independently for each phase of the 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 outlet bushing is less than or equal to the first preset distance threshold. The present invention arranges built-in voltage sensors on the main bus and branch lines. During on-site withstand voltage and operation, the transient voltage is captured to realize online monitoring of transient arcs inside the entire station area GIS. At the same time, the propagation delay of the transient voltage is used in combination with the distance between the measuring points to realize accurate positioning of the arc. The defect type of insulation breakdown can also be determined to improve the accuracy of diagnosis. The method for online monitoring and positioning of transient arcs inside ultra-high voltage full-station area GIS equipment proposed by the present invention realizes rapid judgment of the type of internal insulation fault and accurate positioning of the arc position, which is conducive to timely troubleshooting and improving the quality and efficiency of operation and maintenance, and has a strong application demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings: Figure 1 It is a flow chart of a method 100 for online monitoring of transient arcs in GIS equipment according to an embodiment of the present invention; Figure 2 A schematic diagram of measuring point arrangement according to an embodiment of the present invention; Figure 3 A connection diagram of a monitoring and positioning system according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of a monitoring sensor unit according to an embodiment of the present invention; Figure 5 A schematic diagram of transient voltage excited by a transient arc breakdown of the internal insulation of a GIS according to an embodiment of the present invention; Figure 6 Schematic diagram of the structure of an online monitoring system 600 for transient arc inside GIS equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0024] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0025] Figure 1 FIG. 2 is a flow chart of a method 200 for online monitoring of transient arcs in GIS equipment according to an embodiment of the present invention. Figure 1 As shown, the method for online monitoring of transient arcs inside GIS equipment provided by the embodiment of the present invention arranges built-in voltage sensors on the main bus and branch lines. During on-site withstand voltage and operation, the transient voltage is captured to realize online monitoring of transient arcs inside the entire station-wide GIS. At the same time, the propagation delay of the transient voltage is utilized, combined with the distance between the measuring points, to realize accurate positioning of the arc, and the type of insulation breakdown defect can also be determined to improve the accuracy of diagnosis. The method for online monitoring and positioning of transient arcs inside ultra-ultra-high voltage (UHV) GIS equipment in the entire station-wide GIS proposed by the present invention realizes rapid judgment of the type of internal insulation fault and accurate positioning of the arc, which is conducive to timely troubleshooting and improving the quality and efficiency of operation and maintenance, and has a strong application demand. The method 100 for online monitoring of transient arcs inside GIS equipment provided by the embodiment of the present invention starts from step 101. In step 101, the arrangement of sensor measuring points inside the GIS equipment of the ultra-ultra-high voltage substation is performed.

[0026] The arrangement of sensor measuring points inside the UHV substation GIS equipment includes: Measuring points are arranged on the left and right ends of the two busbars of the GIS equipment of the ultra-high voltage substation and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

[0027] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a hand-hole type sensor based on capacitive voltage division.

[0028] In the present invention, it is first necessary to arrange the built-in sensors of the whole station. In the ultra-high voltage substation, GIS equipment adopts two-thirds wiring, such as Figure 2 As shown. In order to meet the requirements of transient arc monitoring inside GIS equipment in the entire station area, the measurement point layout location needs to be specially configured. First, measurement points are arranged at the left and right ends of the two busbars. Each phase equipment requires an independent measurement point, and the distance from the equipment end does not exceed the first preset distance threshold of 10 meters. Then, monitoring points are also required for the branch outgoing lines between every two circuit breakers (CB for short), and the distance between the monitoring points and the outgoing line bushings does not exceed the first preset distance threshold of 10 meters.

[0029] In the present invention, the built-in sensor adopts a hand-hole sensor based on capacitive voltage division, combined with the hand hole on the GIS cylinder, and a circular plate electrode is built in, with a radius not exceeding 150mm, a thickness not exceeding 20mm, and a distance of not less than 5mm from the inner edge of the GIS cylinder wall. The circular plate electrode and the GIS conductor form a high-voltage arm capacitor. Between the plate electrode and the hand-hole cover, a polyimide film with a relative dielectric constant of 3.5 to 4.5 is used as an insulating medium to construct a low-voltage arm capacitor, and the equivalent capacitance value is not less than 5nF.

[0030] In step 102, during the handover withstand voltage test and operation of the UHV substation GIS equipment, the transient voltage at each measuring point is obtained.

[0031] Preferably, the method further comprises: The transient voltage at each measuring point is obtained by using a monitoring terminal connected to a voltage sensor at the measuring point; wherein the voltage sensor is connected to the monitoring terminal via an N-type cable transition connector.

[0032] Preferably, the monitoring terminal includes: a sampling module, a synchronization module, a synchronization antenna, a power supply 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, it immediately triggers the acquisition card for long-term recording.

[0033] Combination Figure 3 and Figure 4As shown, in the present invention, the transient voltage is obtained through the monitoring terminal. The built-in sensor inside the GIS equipment is connected to the external monitoring terminal, and the monitoring terminal is directly connected to the voltage sensor through an N-type cable transition head. The monitoring terminal includes a sampling module, a synchronous timing module, a synchronous timing 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. In the present invention, the sampling rate of the sampling module is 200MS / s, the sampling analog bandwidth is 100MHz, and the FIFO mode of continuous acquisition and storage is supported. The acquisition module adopts a steepness trigger mode. Once the monitoring waveform exceeds the set steepness, it will immediately trigger the acquisition card for long-term recording. The time accuracy of the timing module is not less than 15ns. The local power supply module draws power from the 220V power supply near the GIS site, and the power supply power is not less than 30W. The upper storage control unit includes an optical switch, a control host (server), a display and a keyboard and other equipment, which can be placed in a screen cabinet in the relay protection room of the substation. The monitoring terminal is connected to the optical switch through a single-mode optical fiber.

[0034] In step 103, it is determined whether a ground breakdown transient arc occurs based on the transient voltage.

[0035] Preferably, determining whether a transient arc to ground breakdown occurs based on the transient voltage comprises: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

[0036] During the handover withstand voltage test and operation, when a transient arc to ground breakdown occurs inside the GIS equipment of the UHV substation, the transient voltage process excited is as follows: Figure 5 When the equipment voltage drops from the positive peak to zero, with a falling edge of less than 200ns, or rises from the negative peak to zero, with a rising edge of less than 200ns, and there is a certain amount of induced voltage afterwards, it is determined that a transient arc to ground breakdown has occurred inside the GIS.

[0037] Therefore, in the present invention, the first preset time threshold can be set to 200ns. When judging the transient arc of internal insulation breakdown to the ground of GIS equipment, for any phase, 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 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, it is determined that a transient arc of breakdown to the ground occurs.

[0038] In step 104, when it is determined that a transient arc to ground breakdown occurs inside the ultra-high voltage substation GIS equipment, the transient arc inside the GIS equipment is located based on the transient voltage to determine the fault location.

[0039] Preferably, the method of locating the transient arc inside the GIS equipment based on the transient voltage to determine the fault location includes: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ', L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

[0040] Preferably, the first distance is determined in the following manner, including: , The second distance is determined by: , The third distance is determined by: , The fourth distance is determined by: , Where c is the propagation speed of electromagnetic waves in GIS.

[0041] In the present invention, fault location can also be performed. First, according to the substation GIS design drawings, the measuring points at both ends of busbar I are set to No. 1 and No. 2, and the distance between the two measuring points is L1, and the measuring points at both ends of busbar II are set to No. 1' and No. 2', and the distance between the two measuring points is L1'; the measuring points of each CB string connected to busbar I and along the direction from measuring point No. 1 to No. 2 are set to No. 3, No. 4, ..., No. n, and the measuring points of each CB string connected to busbar II and along the direction from measuring point No. 1' to No. 2' are set to No. 3', No. 4', ..., No. n', and the distances between measuring points No. 3 to No. n and measuring point No. 1 are L1', L2', L3', L4', L5', L6', L7', L8', L9', L10', L11', L12', L13', L14', L15', L16', L17', L18', L19 ...1', L11', L11', L11', L11', L11', L11', L11', L11', L11', L11', L11', L11 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ',L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is C3', C4', ..., Cn '; 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 to 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 the any phase; The arrival times t1 and t2 of the measuring points at both ends of the I bus of any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 from the fault position to the No. 2 measuring point and the second distance P1' from the fault position to the No. 2 measuring point are determined; If P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then it is determined that the fault location is in the i-th CB string, 3≤i≤n; when the fault location is determined to be in the i-th CB string, secondary positioning is performed, and the measuring point... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

[0042] The first distance is determined by the following method, including: , The second distance is determined by: , The third distance is determined by: , The fourth distance is determined by: , Among them, c is the propagation speed of electromagnetic waves in GIS, which is generally taken as 292m / us.

[0043] Preferably, the method further comprises: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

[0044] In the present invention, combined with Figure 5 As shown, during the withstand voltage test of the ultra-ultra-high voltage GIS equipment, if the duration of the transient voltage excited by the flashover arc to the ground exceeds the first preset time threshold of 1ms, and the falling edge or rising edge time is less than or equal to the third preset time threshold of 150ns, the fault type is the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground is less than or equal to the fourth preset time threshold of 500us, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold of 130ns, the fault type is the SF6 gas gap breakdown. During the operation of the ultra-ultra-high voltage GIS equipment, if the duration of the transient voltage excited by the flashover arc to the ground exceeds the sixth preset time threshold of 100us, and the falling edge or rising edge time is less than or equal to the seventh preset time threshold of 900ns, the fault type is the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground is less than or equal to the sixth preset time threshold of 100us, and the falling edge or rising edge time is less than or equal to the fifth preset time threshold of 130ns, the fault type is the SF6 gas gap breakdown.

[0045] Compared with the existing traditional ultrasonic method, the number of sensors arranged in the method of the present invention is greatly reduced; since the sensors are built-in in the GIS equipment, they have excellent anti-interference performance and no additional sensors need to be arranged during the pressure test. At the same time, the monitoring function can also be realized during the operation stage, which makes up for the shortcomings of the traditional ultrasonic method.

[0046] During the on-site withstand voltage and operation, the transient voltage is captured to realize the online monitoring of the transient arc inside the whole station area GIS. At the same time, the propagation delay of the transient voltage is used, combined with the distance between the measuring points, to quickly locate the arc position and even the secondary discharge position, which is conducive to the timely troubleshooting of faults. The time domain variation characteristics of the transient voltage can be used to accurately judge the arc inside the GIS, effectively eliminate external interference, and determine the defect type of insulation breakdown, thereby improving the accuracy of diagnosis.

[0047] By monitoring the transient arcs of circuit breakers and disconnectors in GIS equipment during operation, it is possible to analyze the dynamic insulation characteristics between moving and static contacts as a fingerprint feature for electrical status assessment.

[0048] The online monitoring method for transient arcs inside ultra-ultra-high voltage full-station GIS equipment proposed in the present invention can realize rapid judgment of the type of internal insulation fault and accurate positioning of the arc, which is conducive to timely troubleshooting. It can also realize the electrical status evaluation of circuit breakers and disconnectors in GIS equipment, improve the quality and efficiency of operation and maintenance, and has strong application demand.

[0049] Figure 6 FIG. 6 is a schematic diagram of the structure of an online monitoring system 600 for transient arc in GIS equipment according to an embodiment of the present invention. Figure 6 As shown, the internal transient arc online monitoring system 600 of GIS equipment 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.

[0050] Preferably, the voltage acquisition unit 601 is used to acquire the transient voltage at each measuring point during the handover withstand voltage test and operation of the ultra-high voltage substation GIS equipment.

[0051] Among them, measuring points are arranged on the left and right ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

[0052] Preferably, a voltage sensor is provided at each measuring point, and the voltage sensor is a hand-hole type sensor based on capacitive voltage division.

[0053] Preferably, the judging unit 602 is used to determine whether a transient arc to ground breakdown occurs based on the transient voltage.

[0054] Preferably, the judging unit 602 determines whether a transient arc to ground breakdown occurs based on the transient voltage, comprising: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

[0055] Preferably, the fault location determination unit 603 is used to locate the transient arc inside the GIS equipment based on the transient voltage to determine the fault location when it is determined that a transient arc that breaks down to the ground occurs inside the ultra-high voltage substation GIS equipment.

[0056] Preferably, the fault location determining unit 603 performs transient arc location inside the GIS equipment based on the transient voltage to determine the fault location, including: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ',L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

[0057] Preferably, the fault location determining unit 603 determines the first distance in the following manner, including: , The second distance is determined by: , The third distance is determined by: , The fourth distance is determined by: , Where c is the propagation speed of electromagnetic waves in GIS.

[0058] Preferably, the system further comprises: a fault type determination unit, configured to: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

[0059] Preferably, the system further comprises: The monitoring terminal is connected to the voltage sensor at the measuring point and is used to obtain the transient voltage at each measuring point; wherein the voltage sensor is connected to the monitoring terminal through an N-type cable transition connector.

[0060] Preferably, the monitoring terminal includes: a sampling module, a synchronization module, a synchronization antenna, a power supply 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, it immediately triggers the acquisition card for long-term recording.

[0061] The GIS equipment internal transient arc online monitoring system 600 of the embodiment of the present invention corresponds to the GIS equipment internal transient arc online monitoring method 100 of another embodiment of the present invention, which will not be described in detail here.

[0062] The present invention has been described with reference to a few embodiments. However, it is known to those skilled in the art that other embodiments than the one disclosed above are equally within the scope of the present invention.

[0063] Generally, all terms used in the present invention are interpreted according to their ordinary meaning in the technical field, unless otherwise explicitly defined therein. All references to "a / said / the [device, component, etc.]" are open to interpretation as at least one instance of the device, component, etc., unless otherwise explicitly stated. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated.

[0064] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0065] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0066] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0067] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for online monitoring of transient arcs in GIS equipment, characterized in that: The method comprises: Arrangement of sensor measurement points inside the UHV substation GIS equipment; During the handover withstand voltage test and operation of GIS equipment in UHV substations, the transient voltage at each measuring point is obtained; determining whether a transient arc to ground breakdown occurs based on the transient voltage; When it is determined that a transient arc to ground breakdown 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; The arrangement of sensor measuring points inside the UHV substation GIS equipment includes: Measuring points are arranged on the left and right ends of the two busbars of the GIS equipment of the ultra-high voltage substation and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

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

3. The method according to claim 1, characterized in that Determining whether a transient arc to ground breakdown occurs based on the transient voltage includes: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

4. The method according to claim 1, characterized in that: Based on the transient voltage, the transient arc inside the GIS equipment is located to determine the fault location, including: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ', L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

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

6. The method according to claim 1, characterized in that The method further comprises: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

7. The method according to claim 1, characterized in that The method further comprises: The transient voltage at each measuring point is obtained by using a monitoring terminal connected to a voltage sensor at the measuring point; wherein the voltage sensor is connected to the monitoring terminal via an N-type cable transition connector.

8. The method according to claim 7, characterized in that The monitoring terminal includes: a sampling module, a synchronization module, a 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. Among them, the acquisition module adopts a steepness trigger mode. When the monitoring waveform exceeds the set steepness, it immediately triggers the acquisition card for long-term recording.

9. An online monitoring system for transient arcs inside GIS equipment, characterized in that: The system comprises: The voltage acquisition unit is used to obtain the transient voltage at each measuring point during the handover withstand voltage test and operation of the GIS equipment in the UHV substation; A judgment unit, used for determining whether a transient arc to ground breakdown occurs based on the transient voltage; A fault location determination unit, for locating the transient arc inside the GIS equipment based on the transient voltage to determine the fault location when it is determined that a transient arc to ground breakdown occurs inside the GIS equipment of the ultra-high voltage substation; Among them, measuring points are arranged on the left and right ends of the two busbars of the ultra-high voltage substation GIS equipment and on the branch lines between every two circuit breakers. Measuring points are arranged independently for each phase of the equipment, and the distance between the measuring point 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 point arranged between the circuit breakers and the outlet bushing is less than or equal to the first preset distance threshold.

10. The system according to claim 9, characterized in that A voltage sensor is provided at each measuring point, and the voltage sensor is a hand-hole type sensor based on capacitive voltage division.

11. The system according to claim 9, characterized in that The judging unit determines whether a transient arc to ground breakdown occurs based on the transient voltage, including: For any phase of any measuring 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 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, it is determined that a transient arc breakdown to the ground has occurred.

12. The system according to claim 9, characterized in that The fault location determination unit locates the transient arc inside the GIS device based on the transient voltage to determine the fault location, including: Set the measuring points at both ends of busbar I to No. 1 and No. 2, and the distance between the two measuring points is L1; set the measuring points at both ends of busbar II to No. 1' and No. 2', and the distance between the two measuring points is L1'; set the measuring points of each CB string connected to busbar I and along the direction from measuring point 1 to No. 2 to No. 3, No. 4, ..., No. n, respectively; set the measuring points of each CB string connected to busbar II and along the direction from measuring point 1' to No. 2' to No. 3', No. 4', ..., No. n', respectively, and the distances between measuring points 3 to n and measuring point 1 are L 2-3 , L 2-4 ,......,L 2-n ; The distances between measuring points 3' to n' and measuring point 1' are L 2-3 ', L 2-4 ',......,L 2-n '; Set the distance from the intersection of each CB string and bus I to the No. 2 measuring point to C3, C4, ..., C n ; The distance from the physical space intersection of each CB string and II busbar to the 2' measuring point is 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 to 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 the any phase at this time; the arrival times t1 and t2 of the measuring points at both ends of the I bus of the any phase, i.e., No. 1 and No. 2, and the arrival times t1' and t2' of the measuring points at both ends of the II bus, i.e., No. 1' and No. 2', as well as 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 are used for the first positioning, and the first distance P1 of the fault position from the No. 2 measuring point and the second distance P1' of the fault position from the No. 2 measuring point are determined; if P1 is not equal to C3, C4, ..., C n Any value or position P1' in the n 'Any value, the fault location is determined to be on the No. I or No. II straight bus; if P1 is equal to C i And position P1' is equal to C i ', then the fault location is determined to be in the i-th CB string, 3≤i≤n; When it is determined that the fault location is within the i-th CB string, secondary positioning is performed, and the measuring point ... connected to 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, and the distance L2 between the first target measuring point and the No. 1 measuring point are determined, and the third distance P2 from the fault location to the first target measuring point is calculated; the measuring point '...' connected to 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, and the distance L2' between the second target measuring point and the No. 1' measuring point are determined, and the fourth distance P2' from the fault location to the second target measuring point is calculated, and the fault location is determined according to the third distance P2 and the fourth distance P2'.

13. The system according to claim 12, characterized in that The fault location determination unit determines the first distance in the following manner, including: ， The second distance is determined by: ， The third distance is determined by: ， The fourth distance is determined by the following method, including: ， Where c is the propagation speed of electromagnetic waves in GIS.

14. The system according to claim 9, characterized in that The system further comprises: a fault type determination unit, configured to: During the acceptance withstand voltage test of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the surface breakdown of the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the ground 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 the SF6 insulation gap breakdown; During the operation of the GIS equipment in the ultra-high voltage substation, if the duration of the transient voltage excited by the flashover arc to the ground 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 the solid insulation component; if the duration of the transient voltage excited by the flashover arc to the 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, the fault type is determined to be SF6 gas gap breakdown.

15. The system according to claim 9, characterized in that The system further comprises: The monitoring terminal is connected to the voltage sensor at the measuring point and is used to obtain the transient voltage at each measuring point; wherein the voltage sensor is connected to the monitoring terminal through an N-type cable transition connector.

16. The system according to claim 15, characterized in that The monitoring terminal includes: a sampling module, a synchronization module, a 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. Among them, the acquisition module adopts a steepness trigger mode. When the monitoring waveform exceeds the set steepness, it immediately triggers the acquisition card for long-term recording.

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