High pressure triggered pulse occluder with adaptive circuit testing

Abstract

A system and method for maintaining electrical stability in a high voltage power transmission system in response to a fault includes detecting a fault, opening a switch to clear the fault, performing an initial pulse test for a predetermined period of time to determine whether the fault still exists, preventing a reclosing operation if the pulse test indicates that the fault still exists, and allowing a reclosing operation if the pulse test indicates that the fault does not exist. If the initial pulse test is inconclusive about the remaining fault, one or more subsequent pulse tests may be performed, preventing a reclosing operation if the pulse test indicates that the fault still exists and allowing a reclosing operation if the pulse test indicates that the fault does not exist.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 232,313, filed August 12, 2021, the entire disclosure of which is expressly incorporated by reference herein for all purposes.

[0002] The present invention relates generally to a system and method for maintaining electrical stability of a power system in response to a fault by pulse testing using a Triggered Vacuum Gap (TVG) device. [Background technology]

[0003] Electricity networks, often referred to as power systems, typically include power plants with generators such as gas turbines, nuclear reactors, coal-fired generators, and hydroelectric dams. Power plants provide electricity at various medium voltages, which are stepped up by transformers to high voltage AC signals and connected to high voltage transmission lines that feed power to substations, usually located in a geographical area, where they are stepped down to medium voltages by transformers for distribution. Substations provide medium voltage power to three-phase feeders, including three single-phase feeders, which provide medium voltage to various distribution transformers and siding connections. Three-phase and single-phase sidings branch off from the feeders that provide medium voltage to various distribution transformers, where the voltage is stepped down to lower voltages for distribution to loads such as homes and businesses. The above types of power networks typically include switching devices, circuit breakers, reclosers, interrupters, etc., that control the flow of power through the network.

[0004] Periodically, faults occur in power networks due to various factors, such as animals touching wires, lightning strikes, falling branches on wires, vehicles hitting utility poles, etc. If such faults cause short circuits and increase the load on the network, the current flow from the substation can increase significantly along the fault path, e.g. many times higher than normal. This amount of current can significantly heat up and even melt the wires, and even cause mechanical damage to various components in the substation and the network. In many cases, such faults are not permanent or bolted faults, but temporary or intermittent faults, and the cause of the fault, e.g. a lightning strike, is removed shortly after the fault occurs and the distribution network starts working normally almost immediately.

[0005] Rapid fault clearing is widely accepted as one of the most effective techniques to improve or maintain the transient stability of the power system while at the same time limiting the let-through current that can damage equipment. Reclosing as soon as possible after the fault is initially cleared can return the circuit to the pre-fault configuration and maintain or restore network stability. Conventional reclosing is most effective only if the fault is cleared, otherwise the full fault current is reapplied every time a hard-reclose is attempted. Reclosing a permanent fault can cause or exacerbate network instability, especially in high-voltage networks where the available fault current can be tens of thousands of amperes. Such large available fault currents can also cause immediate or potential damage to power system equipment. The characteristically low network impedance of high-voltage networks can also cause a rapid increase in the available fault current, which means that the fault current can reach damaging levels very quickly unless it is interrupted very quickly.

[0006] To clear faults very quickly, fault interrupters such as reclosers are often provided with a switch that allows or prevents power flow downstream. Reclosers monitor current flow by detecting current and voltage in the feeder and look for problems in the network circuit, such as detecting faults. If a fault current is detected, the recloser opens accordingly and then closes after a short delay in the process of determining if the fault still exists. If a fault current flows while the recloser is in the closed state, the recloser opens immediately, and if a fault current is detected again or more than once during the subsequent switching operation, the recloser remains open, and the interval between each test may be longer.

[0007] Recloser type devices are known that use pulse testing techniques, in which the switch contacts are opened and closed in a pulsed manner, the pulses typically lasting less than one-half of a current cycle, so that the full fault current is not applied to the network while the recloser determines whether the fault is still present. Pulse closing technologies have been successful in significantly reducing the fault current stress on the network equipment during recloser testing. However, the switching devices required to generate such short pulse durations are relatively complex and expensive. For example, it is well understood by those skilled in the art that vacuum circuit breakers used to generate pulses often use two magnetic actuators, one to close the contacts and one to quickly open the contacts by using the moving mass of the opening actuator to reverse the direction of the closing actuator.

[0008] It has been proposed to employ a TVG device as a switching mechanism for use in pulse testing that does not require moving parts. A typical TVG device includes two stationary main electrodes disposed within a vacuum chamber, with a main vacuum gap defined between them. The TVG device also includes a trigger element, such as a trigger electrode, with a vacuum trigger gap between the trigger electrode and the corresponding main electrode. The trigger gap is designed with a length much shorter than the main vacuum gap so that its breakdown voltage is much lower than that of the main vacuum gap. To further reduce the breakdown voltage of the trigger gap, it may be bridged with an insulator, such as a ceramic. When a sufficiently high trigger voltage impulse is applied across the trigger gap to the main and trigger electrodes, the trigger gap breaks down. This breakdown creates a plasma cloud that propagates through the main vacuum gap in less than a millionth of a second, causing breakdown of the main vacuum gap. This state of the TVG device indicates that the switch is closed. Once current begins to flow through the TVG device, it does not stop until the alternating current signal on the electrodes passes through a zero crossing point. When this happens, the plasma is extinguished by the vacuum and the arc is extinguished. Because the plasma can be ignited inside the vacuum chamber in this way, the timing at which the TVG device conducts can be precisely controlled, i.e., on the order of microseconds, and because there are no moving electrodes, precise mechanical actuation is not required.

[0009] TVG devices can be easily and accurately triggered at relatively low voltages of only a few kV across the main vacuum gap, so the delay associated with the creation of the plasma cloud that effectively closes the switch can be tightly controlled to within a few microseconds of the desired point in time for the pulse test. Once the trigger gap conducts current, it can interrupt even large currents at the first line frequency zero crossing, resulting in a high withstand voltage across the main electrodes immediately after current interruption. Although this function is powerful, it is generally only used for pulsed power applications and not for power systems in synchronous closing applications. More specifically, TVG devices have the excellent ability to not only interrupt high frequency currents, but also line frequency currents at high frequency current zero crossings. This function is important because high frequency currents are generated by the charging and discharging of stray capacitances and inductances during switching operations in power systems. Such high frequency transient currents usually decay very quickly and in most cases are not even noticed when a mechanical switch is performing a closing operation. However, in the case of TVG devices, the high frequency current zero crossings can have the undesirable effect of premature extinguishing of the plasma arc during pulse testing. The TVG device is likely to interrupt the current at one of several high frequency current zeros that occur within 100 microseconds after the current is pulsed in the TVG device. The interruption of the current is a statistical event that depends on physical processes such as the vacuum arc, di / dt, and contact materials. If the plasma arc is extinguished by the high frequency current zero crossing, the TVG device must be re-triggered, but the high frequency transient may occur again, causing a current zero crossing in the TVG current and interrupting the TVG current again.

[0010] If current conduction through the TVG device's plasma arc and the zero crossings of the high frequency current can be maintained in a controlled manner, the TVG device will not cease conduction. A few hundred microseconds after triggering, the line frequency current in the TVG device will be high enough and the high frequency current will decay sufficiently to effectively eliminate the "early" current zero crossings. In other words, if the TVG device maintains conduction through the high frequency current zero crossings for approximately 300 microseconds after trigger failure, then a successful TVG device closing in an electric power distribution or transmission system is likely.

[0011] A variety of fault interrupters and reclosing techniques based on mechanical switches exist for low level distribution systems, but are often not scalable for high voltage transmission systems due to the mechanical stresses resulting from the high voltages and currents, and undesirably require larger and more expensive components. Furthermore, the use of large mechanical components can cause synchronization problems and other problems due to the increased time and energy required to operate the large components. Summary of the Invention [Problem to be solved by the invention]

[0012] For the above reasons, it would be desirable to provide an improved fault detection apparatus and reclosing scheme suitable for use in high voltage power transmission applications. [Means for solving the problem]

[0013] A system and method for maintaining electrical stability in a high voltage transmission or medium voltage distribution system in response to a fault is disclosed and described below, the method including the steps of detecting a fault, opening a switch to clear the fault, performing a pulse test for a predetermined period of time to determine if the fault still exists, preventing a reclosing operation if the pulse test indicates that the fault still exists, and allowing a reclosing operation if the pulse test indicates that the fault does not exist. Subsequent pulse tests may be performed if the first pulse test is inconclusive about the remaining fault, preventing a reclosing operation if the pulse test indicates that the fault still exists and allowing a reclosing operation if the pulse test indicates that the fault does not exist.

[0014] Further features of the present disclosure will become apparent from the following description and claims, taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram of a pulse closing system for a high voltage transmission network. [Diagram 2] FIG. 2 is a cross-sectional view of a TVG device that can be used with the pulse closing device shown in FIG. [Diagram 3] 1 is a graph of time on the horizontal axis and voltage on the vertical axis showing sensitivity to pulse testing and hardware reclosure after one cycle of fault clearance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The following description of disclosed embodiments of a system and method for maintaining electrical stability of a high voltage electrical transmission system in response to a fault using pulse testing is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses.

[0017] Instantaneous balancing of generation and consumption is important to stabilize the power transmission, which is usually achieved by keeping the generation online. When a fault event occurs in the power transmission network, the corresponding reclosing action may cause instability in the power transmission network, which may then do more harm than good, i.e., more widespread power loss due to attempts to restore power. The present disclosure determines when and how to perform a reclosing action after the fault is cleared so that the network does not become unstable. Various parameters, such as voltage angles in the network, are calculated and / or observed to determine whether the network is returning to stability or becoming unstable after the fault is removed to determine whether a reclosing action can be performed. If the network is moving toward stability, a pulse check is performed before the reclosing action is performed to determine whether the fault still exists.

[0018] As described below, the present disclosure proposes a system and method for quickly and repeatedly testing for remaining faults without performing hard reclosing, the system employing a switch with a TVG device. Once the system detects and clears the fault, the switch recloses using point-on-wave timing and other factors to optimize speed and network stability. In the following description, it is assumed that the "switch" consists of three separate poles (one for each phase in a three-phase system) whose operation is coordinated as a single three-pole switch. However, other embodiments allow for independent single-pole actuation, or individual timing for point-on-wave opening and closing for each pole in a three-phase implementation.

[0019] Once a fault is detected using one or more fast fault detection methods, the control issues an initial authorization to clear the suspected fault by actuating a switch optimized for opening speed. While the control is processing from initial authorization to clearance, parallel calculations such as DFT, spectrum analysis, and V-versus-I (impedance) measurements are double-checked to ensure that the suspected fault was not falsely detected. Additionally, to help identify the optimal method for subsequent trigger pulse testing, the type of fault, i.e., single line to ground fault (LG), line to line fault (LL), double line to line to ground (LLG), line to line to line fault (LLL), and three phase line to ground fault (LLLG), is identified as far as possible, increasing the accuracy and speed of determining when any type of fault has cleared.

[0020] In one embodiment, the trigger electrodes of the TVG device are placed only on the fixed contacts of the switch, assumed here as a vacuum interrupter. This allows the trigger pulse test to be performed only once per line frequency cycle, specifically in the half cycle of the positive voltage near the negative voltage zero crossing. In another embodiment, the trigger electrodes are placed on both the fixed and moving contact ends of the vacuum interrupter. This allows the trigger pulse test to be performed twice per line frequency cycle. If the parallel calculation indicates that the fault detection may be a false positive leading to a false trip, the initial permission is withdrawn within the time window in which the switch contacts are operable, and the transition to the trigger pulse closure mode is inhibited.

[0021] If the double-check calculation is slow, incomplete, inconclusive or contradicts the initial fault detection, the initial authorization is strengthened or withdrawn according to a pre-configured selection to avoid false positives or false negatives, depending on what is considered worse for the application. It is also possible to configure the timing for a specific application, which is the system-level double-check of the initial authorization to activate a switch to clear the fault.

[0022] Once a non-false fault has been detected and the switch is opened to clear the fault, the device controls a transition to a trigger pulse closure mode and determines the earliest time the switch can be reclosed by determining when the fault has been cleared. For this, the trigger electrode of the switch is periodically energized at a precise point-on-wave, igniting a plasma arc across the open contact gap. The resulting current, which is of a magnitude much lower than the available fault current and lasts only a few milliseconds, is measured and analyzed to determine whether a fault is still present on any phase. If it is determined that the fault has been cleared, an initial permission is given to reclose the contacts. If the fault has not been cleared, no permission is given and the device waits until the next point-on-wave opportunity to trigger a pulse check.

[0023] Although the interfaces for external current and voltage monitors and external control and status signaling available at substations are described, not all such substations have a communications infrastructure with sufficient bandwidth and data rates required to coordinate local external measurement and control systems with trigger pulse testing. Therefore, for the purposes of this description, it is assumed that voltage and current sensing, and control / status signaling, are performed internal to trigger pulse testing, although such sensing and signaling may be provided by external devices.

[0024] In other embodiments, the control may wait a predetermined time before performing a trigger pulse closure at fixed periodic intervals, the control may wait a set time before performing a trigger pulse closure at variable periodic intervals, the control may stop trigger pulse closures if it is determined that the fault has not been cleared within a predetermined time such as a critical reclose interval, the control may stop trigger pulse closures if it is determined that the fault has not been removed after a specified number of trigger pulse closures have been performed, the control may receive instructions from an external controller to start or stop trigger pulse closures, the control may be configured according to conventional TCC curves or other application specific timing considerations, the control may be configured to not perform a trigger pulse closure at all or to not perform a reclose, the control may adjust the pulse check interval based on the magnitude of the measured fault current, and / or the control of one trigger pulse closure may coordinate with other trigger pulse closures and interleave their respective pulse closure operations to gain additional situational awareness such as fault location or integration of distance and differential relaying schemes.

[0025] 1 is a block diagram of a pulse closure system 10 illustrating components that may be used to maintain electrical stability of a high voltage transmission or medium voltage distribution system in response to a fault. The system 10 includes three high voltage transmission lines 12, 14, 16, respectively on phases A, B, and C, that receive high voltage power from a generator 18, such as a turbine. A pulse closure device 20 is coupled to the high voltage transmission lines 12, 14, 16 and includes a switch assembly 22 having a reclosing switch 24, such as a vacuum interrupter, and a pulse checking TVG device 26 on the high voltage transmission line 12, a switch assembly 28 having a reclosing switch 30 and a pulse checking TVG device 32 on the high voltage transmission line 14, and a switch assembly 34 having a reclosing switch 36 and a pulse checking TVG device 38 on the high voltage transmission line 16. The pulse closure system 20 also includes an actuator control 40 that opens and closes the reclosing switches 24, 30, 36 during fault clearing and reclosing operations, and a trigger control 42 that generates plasma arcs in the TVG devices 26, 32, 38.

[0026] Voltage sensor 48 is coupled to high voltage transmission lines 12, 14 on the transmission side of pulse closing device 20, and voltage sensor 50 is coupled to high voltage transmission lines 14, 16 on the transmission side of pulse closing device 20 to provide voltage measurements on the high voltage transmission lines. Voltage monitor 52 receives voltage measurements from voltage sensors 48 and 50. Current sensor 54 provides current measurements on high voltage transmission line 12, current sensor 56 provides current measurements on high voltage transmission line 14, and current sensor 58 provides current measurements on high voltage transmission line 16. Current monitor 60 receives current measurements from current sensors 54, 56, 58. Voltage monitoring in this configuration uses line voltage measurements from voltage sensors 48 and 50. In an alternative embodiment, the voltage measurements may be line-to-ground voltage measurements requiring three voltage sensors. A signal processor 62 receives the voltage and current signals from monitors 52 and 60, processes the signals, and provides the processed signals to a fault detection and response logic controller 64. The fault detection and response logic controller 64 commands the actuator control 40 and trigger control 42 to control the reclose switches 24, 30, 36 and TVG devices 26, 32, 38 in a manner consistent with that described herein. The signal processor 62 communicates with a communication device 66 to receive voltage and current signals, status signals, etc. from other components in the network.

[0027] While the TVG devices 26, 32, 38 may be any TVG device suitable for the purposes described herein, one representative example is shown in FIG. 2, which is a cross-sectional view of an exemplary embodiment of an electrically triggered TVG device 70. The TVG device 70 includes a vacuum enclosure 72 having a cylindrical insulator 74 and conductive end plates 76, 78. In the exemplary embodiment, the vacuum enclosure 72 is 10 -6 mbar or more, 10 -3 The TVG device 70 is sealed at a vacuum pressure of less than mbar. The TVG device 70 also includes a pair of opposing conductive electrodes 82, 84 defining a trigger gap 86 therebetween. Electrode 82 is connected to a stem 88 that extends through a sealed hole in the end plate 76, and electrode 84 is connected to a stem 90 that extends through a sealed hole in the end plate 78, by which the TVG device 70 is connected to other switching elements. The inner surface of the insulator 74 is protected from conductive deposits by a cylindrical metal vapor shield 92.

[0028] The pulse trigger circuit 94 generates a sufficient high voltage / low current pulse across the trigger gap 86 to initiate the plasma arc, which is then maintained for hundreds of microseconds by a low voltage / high current pulse. In an exemplary embodiment, the duration of the initial high voltage / low current pulse is a few microseconds, and the duration of the low voltage / high current pulse is a few hundred microseconds. The geometry of the arrangement between the trigger electrode and its target surface focuses the initial pulse to a very small area of ​​the electrode 82, expanding the power density of the trigger pulse on the electrode surface, and the electrical trigger energy transferred to the electrode results in near instantaneous vaporization of the electrode material and transition of the vapor into a high density plasma cloud 96 that expands as a plasma plume toward the electrode 74, resulting in electrical breakdown of the gap 106 and the creation of a vacuum arc between the electrodes 82 and 84. The breakdown of the gap occurs based on the magnitude of the voltage difference between the electrodes 82 and 84 after the plasma cloud 96 is created. The electrode material can be selected based on its triggering capability, i.e., ablation capability under the laser pulse, along with its vacuum arc interruption capability and dielectric strength in vacuum.

[0029] 3 is a graph, with the horizontal axis being time and the vertical axis being voltage, illustrating the sensitivity of pulse testing and hard reclosing after one cycle of fault clearing of a permanent fault. Graph line 110 represents the voltage of one of the high voltage transmission lines 12, 14, 16. The fault is detected by current and voltage measurements, and the appropriate reclose switch 24, 30, or 36 is opened and the fault is cleared at time location (elapsed time) 112. The voltage on that line then begins to stabilize and a reclosing operation is set to occur at time location (elapsed time) 114 to determine if the fault is still present, but due to the permanent fault, the fault still exists. Graph line 116 represents a 0.5 cycle pulse test, graph line 118 represents a 1.5 cycle pulse test, graph line 120 represents a 2.5 cycle hard reclosing and reopening, and graph line 122 represents a 3.5 cycle hard reclosing and reopening, which may occur at time location 114. Graph lines 120 and 122 show that for a conventional hardware reclosing, a fault may be back-introduced into the network, tripping the generator 18 and resulting in system stability. A 0.5 or 1.5 cycle fast pulse check, as shown by graph lines 116 or 118, indirectly maintains system stability by keeping generation online while a permanent fault is present, as compared to a conventional 2.5 or 3.5 cycle hardware reclosing followed by a reclosing. In this case, the hardware reclosing results in a generator voltage drop compared to the pulse check, indicating a trip-offline, indicating that the fault is still present and no reclosing action is taken.

[0030] In this disclosure, an initial point-on-wave pulse test is performed using a suitable TVG device 26, 32, or 38 at elapsed time 114 to detect the presence of a fault, e.g., within 0.5 cycles, but without significant fault current flowing on the transmission line. If the pulse test determines that the fault has been cleared by the system, then reclosing is permitted. Because pulse tests are generally less disruptive to the network than hardware reclosing, pulse tests can be applied repeatedly or limited by configuration until the fault is determined to be permanent and the device is locked out, or the fault is determined to no longer apply to the system and the recloser is permitted to reclose. Thus, if the initial pulse test does not provide an adequate determination of whether the fault is still present, multiple pulse tests can be performed for the same or longer time periods.

[0031] Pulse testing is low energy, i.e. the amount of current tolerated by the equipment if the fault persists is significantly less than the available fault current, thus avoiding both obvious and latent damage caused by the let-through current of transformers and circuit breakers. Pulse testing needs to be performed within the critical reclosing interval to minimize disturbance on the network. However, simulation results suggest that pulse testing too early can destabilize the transmission network in the presence of a permanent fault.

[0032] The foregoing disclosure discloses and describes merely exemplary embodiments of the present invention. Those skilled in the art will readily recognize from the above description and the accompanying drawings and claims that various changes, modifications, and variations can be made without departing from the spirit and scope of the present disclosure, as defined in the following claims. [Explanation of symbols]

[0033] 10 Pulse Closure System 12, 14, 16 High voltage power lines 18. Generator 20 Pulse Closure Device 22, 28, 34 Switch Assembly 24, 30, 36 Reclosing switch 26, 32, 38 Pulse inspection TVG equipment 40 Actuator Control 42 Trigger Control 48, 50 Voltage sensor 52 Voltage Monitor 54, 56, 58 Current sensors 60 Current Monitor 62 Signal Processor 64 Fault detection and response logic controller 66 Communication Equipment 70 TVG equipment 72 Vacuum enclosure 74 Cylindrical Insulator 76, 78 Conductive end plate 82, 84 conductive electrode 86 Trigger Gap 88, 90 stem 92 Metal Vapor Shield 94 Pulse Trigger Circuit 96 Plasma Cloud 110 Graph line (voltage of any of high voltage transmission lines 12, 14, 16) 112, 114 Time position (elapsed time) 116 Graph line (0.5 cycle pulse test) 118 Graph line (1.5 cycle pulse test) 120 Graph line (2.5 cycles of hardware reclosing and reopening) 122 Graph line (3.5 cycles of hardware reclosing and reopening)

Claims

1. A method for maintaining the electrical stability of a power system in response to a fault, comprising: detecting the fault; opening a switch to remove the fault; performing an initial pulse inspection for a predetermined time using a vacuum trigger gap (TVG) device integrated with the switch to determine whether the fault still exists; preventing reclosing operation by the switch if it is indicated in the initial pulse inspection that the fault still exists; permitting the reclosing operation if it is indicated in the initial pulse inspection that the fault does not exist and characterized by including the above steps.

2. The method according to claim 1, wherein the predetermined time is within 0.5 cycles.

3. The method according to claim 1, further comprising performing subsequent pulse inspections when no conclusion has been reached regarding the persistence of the fault in the initial pulse inspection, and the step of preventing the reclosing operation from being performed includes preventing the reclosing operation if it is indicated in any of the pulse inspections that the fault still exists, and permitting the reclosing operation if it is indicated in any of the pulse inspections that the fault does not exist.

4. The method according to claim 1, wherein the initial pulse inspection is performed at a predetermined point-on-wave time.

5. The method according to claim 1, wherein the power system is a high-voltage power transmission system.

6. A method for maintaining the electrical stability of a high-voltage power transmission system in response to a fault, comprising: detecting the fault; opening a switch to remove the fault; performing an initial pulse inspection for a predetermined time using a vacuum trigger gap (TVG) device integrated with the switch to determine whether the fault still exists; when no conclusion has been reached regarding the persistence of the fault in the initial pulse inspection, performing subsequent pulse inspections for the predetermined time with the integrated TVG device; preventing reclosing operation by the switch if it is indicated in the pulse inspection that the fault still exists; permitting reclosing operation by the switch if it is indicated in the pulse inspection that the fault does not exist and characterized by including the above steps.

7. The method according to claim 6, wherein the predetermined time is within 0.5 cycles.

8. The method according to claim 6, characterized in that the initial pulse inspection is performed at a predetermined point-on-wave time. **Claim 9** A system for maintaining the electrical stability of a power network in response to a fault, a sensor connected to the power network for detecting the fault and a control device connected to the sensor, an actuator connected to a switch, the actuator removing the fault by opening the switch when a fault exists, a vacuum trigger gap (TVG) device integrated with the switch that performs an initial pulse inspection of the power network for a predetermined time to determine whether the fault still exists, comprising: the actuator being configured to prevent reclosing of the switch when it is indicated that the fault still exists in the initial pulse inspection, and the actuator being configured to perform reclosing of the switch when it is indicated that the fault does not exist in the initial pulse inspection. A system characterized by this. **Claim 10** The system according to claim 9, characterized in that the predetermined time is within 0.5 cycles. **Claim 11** When it is indicated that the fault exists in the initial pulse inspection, the integrated vacuum trigger gap (TVG) device is configured to perform subsequent pulse inspections. Further, the actuator is configured to prevent reclosing of the switch when it is indicated that the fault still exists in the subsequent pulse inspection, and the actuator is configured to perform reclosing when it is indicated that the fault does not exist in the subsequent pulse inspection. The system according to claim 9, characterized by this. **Claim 12** The system according to claim 11, characterized in that the predetermined time is within 0.5 cycles. **Claim 13** The system according to claim 9, characterized in that the integrated vacuum trigger gap (TVG) device is configured to perform the initial pulse inspection at a predetermined point-on-wave time. **Claim 14** The system according to claim 9, characterized in that the power network is a high-voltage transmission network.

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