Compensation current determination method and device of active arc extinction system and active arc extinction system

Abstract

This invention discloses a method, apparatus, and active arc suppression system for determining the compensation current. The method includes: acquiring the zero-sequence current measurements for each phase line in the active arc suppression system; determining the faulty line and its relative position within the faulty line based on the multiple zero-sequence current measurements; identifying the target arc suppression device closest to the fault point from among multiple active arc suppression devices based on the relative position; and determining the compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device. This invention solves the technical problem of poor performance in centralized compensation methods for single-phase grounding faults in related technologies.

Description

Technical Field

[0001] This invention relates to the field of arc suppression technology for power distribution networks, and more specifically, to a method and apparatus for determining the compensation current of an active arc suppression system, as well as an active arc suppression system. Background Technology

[0002] When a single-phase ground fault occurs in a power distribution system, traditional centralized compensation methods, such as grounding the neutral point through an arc suppression coil to provide basic inductive compensation current or directly injecting active current at the neutral point, face challenges in terms of dynamic response speed and flexibility of compensation capacity allocation in modern power distribution networks with high cable coverage.

[0003] If an arc suppression coil and an active injection device are connected in parallel to inject compensation current into the neutral point of the system, the residual current at the fault point (or the zero-sequence current at the key monitoring point) during a single-phase ground fault is:

[0004]

[0005] in: It is residual current. The sum of the line's total capacitance to ground and its conduction current to ground. It is the inductive current of the arc suppression coil when a fault occurs. It refers to the magnitude of the injected current after the injection-type arc suppression device is activated following a fault.

[0006] When the device injects current Then, it propagates along the conductor towards the fault point. During this process, a portion of the current is continuously diverted to the ground by the parallel ground capacitance. Therefore, the current in the conductor gradually decreases from the injection point until it reaches the fault point. The longer the line, the greater the difference between the compensation current to the fault point and the actual required compensation current. Therefore, for faults at the end of long lines, the line impedance... This will lead to a decrease in the compensation effect. At the same time, due to the presence of series impedance, the voltage along the line will gradually decrease.

[0007] There is currently no effective solution to the above problems. Summary of the Invention

[0008] This invention provides a method, apparatus, and active arc suppression system for determining the compensation current of an active arc suppression system, in order to at least solve the technical problem of poor performance of centralized compensation methods for single-phase grounding faults in related technologies.

[0009] According to one aspect of the present invention, a method for determining the compensation current of an active arc suppression system is provided, comprising: acquiring zero-sequence current measurement values ​​corresponding to multi-phase lines in the active arc suppression system, wherein the active arc suppression system includes an arc suppression coil, zero-sequence current transformers corresponding to the multi-phase lines, and a plurality of active arc suppression devices, the plurality of active arc suppression devices being respectively disposed at different positions from the beginning of the corresponding line, the corresponding zero-sequence current transformers being disposed at the beginning of the corresponding line, and the arc suppression coils being disposed between the neutral point and the grounding grid; determining a faulty line from the multi-phase lines based on the plurality of zero-sequence current measurement values, and the relative position of the fault point in the faulty line; determining a target arc suppression device closest to the fault point at a target location from the plurality of active arc suppression devices based on the relative position; and determining a compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device.

[0010] Optionally, determining the compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device includes: when the arc suppression parameters include equivalent impedance and line injection voltage, obtaining the angular frequency corresponding to a predetermined power frequency, the inductance value of the arc suppression coil, the total admittance corresponding to the multiphase line, and the upstream zero-sequence impedance upstream of the fault point, wherein the total admittance is determined based on the capacitance to ground and conductance to ground of the healthy phase line and the capacitance to ground and conductance of the line upstream of the fault point in the fault line; and determining the compensation injection current value based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance.

[0011] Optionally, determining the compensation injection current value based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance includes: obtaining the downstream zero-sequence impedance downstream of the fault point; and determining the compensation injection current value based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, the upstream zero-sequence impedance, and the downstream zero-sequence impedance.

[0012] Optionally, determining the compensation injection current value based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance includes: determining a first term based on the inductance and the angular frequency; obtaining a first sum based on the sum of the reciprocal of the first term and the total admittance, and determining the sum of the upstream zero-sequence impedance, the downstream zero-sequence impedance, and the equivalent impedance to obtain a second sum; determining the product of the first sum and the line injection voltage to obtain a first product, and determining the product of the first term and the second sum to obtain a second product, and determining the product of the total admittance and the second sum to obtain a third product; determining a predetermined coefficient, the sum of the second product and the third product to obtain a fourth sum; and determining the ratio of the first product to the fourth sum to obtain the compensation injection current value.

[0013] Optionally, determining the compensation injection current value based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance includes: determining a first term based on the inductance and the angular frequency; determining the sum of the first term and the upstream zero-sequence impedance to obtain a fifth sum; determining the sum of the reciprocal of the fifth sum and the total admittance to obtain a sixth sum; determining the product of the sixth sum and the line injection voltage to obtain a fourth product, and determining the product of the sixth sum and the equivalent impedance to obtain a fifth product; determining the sum of the fifth product and a predetermined coefficient to obtain a seventh sum; and determining the ratio of the fourth product to the seventh sum to obtain the compensation injection current value.

[0014] Optionally, after determining the compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device, the method further includes: controlling the target arc suppression device to inject the compensation injection current value into the faulty line to perform a ground residual current cancellation operation to suppress the residual current at the fault point.

[0015] According to one aspect of the present invention, an active arc suppression system is provided, comprising: an arc suppression coil, a zero-sequence current transformer corresponding to a multi-phase line, and a plurality of active arc suppression devices, wherein the plurality of active arc suppression devices are respectively disposed at different positions from the beginning of the corresponding line, the corresponding zero-sequence current transformer is disposed at the beginning of the corresponding line, and the arc suppression coil is disposed between the neutral point and the grounding grid.

[0016] According to one aspect of the present invention, a compensation current determination device for an active arc suppression system is provided, comprising: an acquisition module, configured to acquire zero-sequence current measurement values ​​corresponding to multi-phase lines in the active arc suppression system, wherein the active arc suppression system includes an arc suppression coil, zero-sequence current transformers corresponding to the multi-phase lines, and a plurality of active arc suppression devices, the plurality of active arc suppression devices being respectively disposed at different positions from the beginning of the corresponding line, the corresponding zero-sequence current transformers being disposed at the beginning of the corresponding line, and the arc suppression coils being disposed between the neutral point and the grounding grid; a first determination module, configured to determine a faulty line from the multi-phase lines based on the plurality of zero-sequence current measurement values, and the relative position of the fault point in the faulty line; a second determination module, configured to determine a target arc suppression device closest to the fault point at a target orientation based on the relative position from the plurality of active arc suppression devices; and a third determination module, configured to determine a compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device.

[0017] According to one aspect of the present invention, an electronic device is provided, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to execute the instructions to implement the compensation current determination method for an active arc suppression system as described in any of the preceding claims.

[0018] According to one aspect of the present invention, a computer-readable storage medium is provided, which, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the compensation current determination method for an active arc suppression system as described above.

[0019] In this embodiment of the invention, the zero-sequence current measurement values ​​corresponding to the multi-phase lines in the active arc suppression system are obtained. The active arc suppression system includes an arc suppression coil, a zero-sequence current transformer corresponding to each multi-phase line, and multiple active arc suppression devices. The multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding line, the corresponding zero-sequence current transformer is set at the beginning of the corresponding line, and the arc suppression coil is set between the neutral point and the grounding grid. Based on the multiple zero-sequence current measurement values, the faulty line and the relative position of the fault point in the faulty line are determined from the multi-phase lines. Based on the relative position, the target arc suppression device closest to the fault point in the target orientation is determined from the multiple active arc suppression devices. Based on the arc suppression parameters corresponding to the target arc suppression device, the compensation injection current value is determined. This method employs a collaborative compensation approach using arc-suppression coils and distributed active arc-suppression devices, with the target arc-suppression device near the fault point triggering the injection of compensation current. By acquiring the zero-sequence current measurement values ​​of multi-phase lines, the relative location of the faulty line and fault point is determined. The nearest target arc-suppression device is selected, and the compensation injection current value is determined based on its arc-suppression parameters. The compensation current is precisely injected at a suitable electrical node near the fault point, actively reconstructing the zero-sequence current path after the fault. This achieves precise cancellation of residual current at the fault point, rapid on-site elimination of single-phase grounding faults, and reduces the shunting and distortion effects of line impedance on the compensation current. It realizes the goal of precise tracking and effective compensation of the compensation current, thereby achieving precise suppression and intelligent management of single-phase grounding faults. It achieves millisecond-level, near-zero residual current arc-suppression effects, effectively complementing centralized compensation within the station. This ensures stable bus voltage without affecting the operation of other normal lines, thus solving the technical problem of poor performance of centralized compensation methods for single-phase grounding faults in related technologies. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0021] Figure 1 This is a flowchart of a method for determining the compensation current of an active arc suppression system according to an embodiment of the present invention;

[0022] Figure 2 This is a circuit diagram provided by an optional embodiment of the present invention, showing that the fault point occurs downstream of the zero-sequence current transformer and upstream of the active arc suppression device.

[0023] Figure 3 This is an equivalent zero-sequence circuit diagram provided by an optional embodiment of the present invention, in which the fault point occurs downstream of the zero-sequence current transformer and upstream of the active arc suppression device.

[0024] Figure 4 This is a circuit diagram of the active arc suppression device and the arc suppression coil installed at the neutral point according to an optional embodiment of the present invention;

[0025] Figure 5 This is an equivalent zero-sequence circuit diagram of an active arc suppression device and an arc suppression coil installed at a neutral point, provided by an optional embodiment of the present invention.

[0026] Figure 6 This is a current relationship diagram between the active arc suppression device and the arc suppression coil installed at the neutral point, provided by an optional embodiment of the present invention;

[0027] Figure 7 This is a circuit diagram provided by an optional embodiment of the present invention, showing that the fault point occurs downstream of the zero-sequence current transformer and downstream of the active arc suppression device.

[0028] Figure 8 This is an equivalent zero-sequence circuit diagram provided by an optional embodiment of the present invention, where the fault point occurs downstream of the zero-sequence current transformer and downstream of the active arc suppression device. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] Example 1

[0032] According to an embodiment of the present invention, an embodiment of a method for determining the compensation current of an active arc suppression system is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] Figure 1This is a flowchart of a method for determining the compensation current of an active arc suppression system according to an embodiment of the present invention, as follows: Figure 1 As shown, the method includes the following steps:

[0034] Step S102: Obtain the zero-sequence current measurement values ​​corresponding to the multi-phase lines in the active arc suppression system. The active arc suppression system includes an arc suppression coil, a zero-sequence current transformer corresponding to the multi-phase lines, and multiple active arc suppression devices. The multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding line. The corresponding zero-sequence current transformer is set at the beginning of the corresponding line. The arc suppression coil is set between the neutral point and the grounding grid.

[0035] The active arc suppression system refers to the distributed arc suppression system designed for single-phase grounding faults in distribution networks in this invention. Its core components include arc suppression coils, zero-sequence current transformers, and active arc suppression devices. It can achieve coordinated compensation between the arc suppression coils and the distributed active arc suppression devices. For example, it is suitable for arc suppression of single-phase grounding faults in modern distribution networks with high cable coverage.

[0036] Multiphase lines refer to power supply lines composed of multiple phases in a distribution network. They are the core transmission carriers of the distribution system and can realize the transmission and distribution of electrical energy, such as the A-phase, B-phase, and C-phase lines in a three-phase four-wire distribution network.

[0037] Among them, the zero-sequence current measurement value refers to the specific value obtained by the zero-sequence current transformer from the zero-sequence current detection of the line. It can intuitively reflect whether there is a grounding fault in the line and the degree of the fault. For example, if the zero-sequence current measurement value of a certain phase line exceeds the preset threshold, it indicates that the line is likely to have a single-phase grounding fault.

[0038] Among them, the arc suppression coil refers to the inductor coil connected between the neutral point and the grounding grid in the power distribution system. It can provide basic inductive compensation current and significantly reduce the portion of the total current flowing to the fault point that comes from the healthy lines. For example, in a power distribution network where the neutral point is grounded through the arc suppression coil, the arc suppression coil can compensate for the ground capacitance current of the healthy lines.

[0039] Among them, the zero-sequence current transformer refers to the sensing device used to detect the zero-sequence current of a line. It can accurately collect the zero-sequence current signal of the line and convert it into a measurable value. For example, the zero-sequence current transformer installed at the beginning of the line can monitor the changes in the zero-sequence current of the line in real time.

[0040] Among them, active arc suppression devices refer to arc suppression equipment that can actively inject compensation current into the line. They can act as precision compensators to eliminate residual current at fault points. For example, active arc suppression devices that are evenly distributed at different locations on the line can inject compensation current into the fault point nearby.

[0041] The beginning of the line refers to the starting point where the line connects to the busbar of the substation. It is a key node for line fault monitoring and can realize comprehensive monitoring of the zero-sequence current of the entire line. For example, the connection between the outgoing line of the distribution network and the busbar of the substation is the beginning of the line.

[0042] The neutral point refers to the common connection point of the three-phase windings connected in a star configuration in a power distribution system. It is the core connection node of the arc suppression coil and provides the foundation for the grounding connection of the arc suppression coil. For example, the common terminal of the star winding of a power distribution transformer is the neutral point.

[0043] Among them, the grounding grid refers to the grounding system composed of grounding electrodes and grounding wires, which can realize the safe grounding of the power distribution system and provide a return path for the inductive current of the arc suppression coil. For example, the grounding grid in the substation is composed of metal conductors and grounding electrodes.

[0044] In this step, the zero-sequence current of each phase line in the distributed active arc suppression system of the distribution network can be collected through the zero-sequence current transformer at the beginning of each line. The hardware layout of the system is such that the arc suppression coil is connected between the neutral point and the grounding grid, and the active arc suppression devices are distributed at different locations on each line away from the beginning. Through this step, comprehensive and accurate collection of the zero-sequence current of the distribution network lines is completed, providing raw data support for the subsequent identification of faulty lines and fault points. At the same time, the distributed hardware layout of the system lays the hardware foundation for the subsequent triggering of the active arc suppression device nearby. The zero-sequence current transformer at the beginning of the line ensures that the zero-sequence current measurement value can cover the entire line, avoiding missed fault signals.

[0045] In this step, zero-sequence current transformers are set up individually for each phase and installed at the beginning of the line. This enables independent, full-section monitoring of the zero-sequence current of multi-phase lines, accurately capturing changes in the zero-sequence current of any single phase. This provides reliable data for subsequent fault diagnosis and avoids missed faults due to monitoring blind spots. The layout of the arc suppression coil connected between the neutral point and the grounding grid provides basic inductive compensation hardware support for the system in advance. The distributed arrangement of the active arc suppression device breaks the hardware limitations of traditional centralized compensation, creating hardware conditions for subsequent local compensation and reducing the impact of line impedance. At the same time, the zero-sequence current transformer can acquire zero-sequence current measurements in real time, providing rapid feedback on the line's operating status and ensuring the timeliness of subsequent fault diagnosis. This meets the requirements of dynamic response speed for arc suppression in distribution networks.

[0046] Step S104: Based on multiple zero-sequence current measurements, determine the faulty line from the multi-phase lines, and the relative position of the fault point within the faulty line.

[0047] Among them, the faulty line refers to a single-phase ground fault in a multi-phase line. It is the core processing object of arc suppression in the distribution network and can clarify the specific line range of arc suppression compensation. For example, if the zero-sequence current measurement value of phase A exceeds the threshold, phase A is determined to be the faulty line.

[0048] Among them, the fault point refers to the specific location where a ground fault occurs in the faulty line. It is the precise target point for the compensation current and can clearly identify the specific location of the arc suppression compensation. For example, if a ground fault occurs at a line node 800 meters away from the beginning of the faulty line, that node is the fault point.

[0049] The relative position refers to the positional relationship of the fault point in the faulty line relative to the distributed active arc suppression devices (before / after the fault point). It can determine the triggering direction of the active arc suppression devices. For example, if the fault point is located between two active arc suppression devices, it can be determined that the fault point is behind the upstream device and in front of the downstream device.

[0050] In this step, the zero-sequence current measurements of the collected multi-phase lines are compared with preset thresholds. Lines with zero-sequence current measurements exceeding the thresholds are identified as faulty lines. Then, combining the characteristics of the zero-sequence current changes in the faulty lines with existing technology, the relative position of the fault point within the faulty line relative to each active arc-suppression device is analyzed and determined. This step accurately locates the faulty line from the multi-phase lines, clarifies the positional relationship between the fault point and the active arc-suppression devices, eliminates interference from intact lines, and provides a core basis for subsequent accurate selection of the target arc-suppression device.

[0051] This step uses a comparison method based on zero-sequence current measurements to determine the faulty line. This method can quickly distinguish the faulty line from the healthy line in a multi-phase circuit, avoiding ineffective arc suppression operations on healthy lines. This effectively improves the working efficiency of the arc suppression system and reduces unnecessary equipment losses. Furthermore, determining the relative position of the fault point with respect to the active arc suppression device, rather than just its physical location, provides a clear basis for which active arc suppression device to trigger subsequently. This is highly consistent with the design logic of the distributed active arc suppression of this invention, avoiding compensation failure caused by blindly triggering the device. At the same time, the judgment of the faulty line and its relative position is based directly on the zero-sequence current measurement value. The judgment logic is simple and the response speed is fast, effectively solving the problem of slow dynamic response in traditional centralized compensation and meeting the real-time requirements of arc suppression in distribution networks.

[0052] Step S106: Based on the relative position, determine the target arc suppression device that is closest to the fault point in the target orientation from among multiple active arc suppression devices;

[0053] The target orientation refers to the specific orientation that needs to be triggered by the active arc suppression device, determined based on the relative position of the fault point. That is, before or after the fault point, the triggering range of the active arc suppression device can be clearly defined. For example, if the fault point is downstream of the zero-sequence transformer and upstream of the active arc suppression device, the target orientation is after the fault point.

[0054] Among them, the target arc extinguishing device refers to the active arc extinguishing device selected from multiple active arc extinguishing devices that is located at the target location and is closest to the fault point. It is an execution device that injects compensation current into the faulty line and can achieve precise injection of compensation current nearby. For example, the active arc extinguishing device closest to the fault point is the target arc extinguishing device.

[0055] In this step, based on the relative position of the fault point within the faulty line, the target location of the active arc suppression device to be triggered (before / after the fault point) is first determined. Then, from all active arc suppression devices at that location, the device with the closest physical distance to the fault point is selected as the target arc suppression device. Through this step, the active arc suppression device is accurately selected, and the injection node for the compensation current is determined, laying the foundation for subsequent accurate calculation of the compensation injection current value and execution of the injection operation.

[0056] This step selects the target arc suppression device closest to the fault point, which can minimize the transmission path of the compensation current from the injection point to the fault point. This effectively solves the problem of long compensation current transmission paths in traditional centralized compensation, and significantly reduces the impact of the compensation current being shunted by the ground capacitance and line impedance during transmission. The method of determining the target location first and then selecting the nearest device avoids triggering active arc suppression devices in the wrong location, ensuring that the injection direction of the compensation current matches the flow direction of the fault current. This can effectively reconstruct the zero-sequence current path after the fault, improve the effectiveness of arc suppression compensation, and trigger only the single target arc suppression device closest to the target location, rather than triggering multiple devices at the same time. This achieves precise allocation of arc suppression resources, avoids resource waste caused by multiple devices working at the same time, and also reduces the control complexity of multi-device coordination.

[0057] Step S108: Determine the compensation injection current value based on the arc extinguishing parameters corresponding to the target arc extinguishing device.

[0058] Among them, arc suppression parameters refer to various electrical parameters related to the target arc suppression device and power distribution network system, which are used to calculate the compensation injection current value. They can provide data support for the accurate calculation of the compensation injection current value, such as injection voltage, power frequency angular frequency, arc suppression coil inductance, upstream and downstream zero-sequence impedance of the fault point, and equivalent impedance of the active arc suppression device.

[0059] Among them, the compensation injection current value refers to the specific value of the compensation current that the target arc extinguishing device needs to inject into the faulty line, which is calculated based on the arc extinguishing parameters. It is the core execution parameter of the target arc extinguishing device and can achieve precise cancellation of the residual current at the fault point. For example, the calculated compensation injection current value can completely cancel the sum of the ground capacitance current and the conduction current at the fault point.

[0060] In this step, various arc-suppression parameters corresponding to the target arc-suppression device are retrieved. These parameters are then substituted into the pre-defined compensation current calculation formulas of this invention (the formulas for triggering after the fault point and for triggering before the fault point) to calculate the final compensation injection current value injected by the target arc-suppression device into the faulty line. This step completes the accurate calculation of the compensation current value, providing specific execution values ​​for the actual injection operation of the target arc-suppression device and ensuring that the compensation current matches the actual residual current requirements of the fault point.

[0061] This step calculates the compensation injection current value based on the arc suppression parameters and dedicated calculation formula corresponding to the target arc suppression device. It fully considers actual electrical factors such as the upstream and downstream zero-sequence impedance of the fault point, the inductance of the arc suppression coil, and the equivalent impedance of the device, so that the calculated current value is highly matched with the actual residual current demand at the fault point. It can achieve accurate cancellation of residual current and effectively solve the problem of large deviation between compensation current and actual demand in traditional centralized compensation. At the same time, the corresponding calculation formula is selected according to the target location, and the influence of the downstream zero-sequence impedance of the fault point (triggered after the fault point) and only the upstream zero-sequence impedance of the fault point (triggered before the fault point) are considered respectively. This makes the calculation logic highly consistent with the actual fault scenario, avoids the compensation deviation caused by single formula calculation, and achieves accurate calculation based on the scenario. The accurate compensation injection current value can achieve almost complete cancellation of the residual current at the fault point. Combined with the nearby injection method, it can achieve the arc suppression effect of millisecond level and near-zero residual current. At the same time, it can effectively avoid over-compensation or under-compensation, ensure the stable operation of the distribution network, and will not affect the bus voltage and other healthy lines.

[0062] Through the above steps S102-S108, the zero-sequence current measurement values ​​corresponding to the multi-phase lines in the active arc suppression system are obtained. The active arc suppression system includes an arc suppression coil, a zero-sequence current transformer corresponding to each multi-phase line, and multiple active arc suppression devices. The multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding line, the corresponding zero-sequence current transformer is set at the beginning of the corresponding line, and the arc suppression coil is set between the neutral point and the grounding grid. Based on the multiple zero-sequence current measurement values, the faulty line and the relative position of the fault point in the faulty line are determined from the multi-phase lines. Based on the relative position, the target arc suppression device closest to the fault point in the target orientation is determined from the multiple active arc suppression devices. Based on the arc suppression parameters corresponding to the target arc suppression device, the compensation injection current value is determined. This method employs a collaborative compensation approach using arc-suppression coils and distributed active arc-suppression devices, with the target arc-suppression device near the fault point triggering the injection of compensation current. By acquiring the zero-sequence current measurement values ​​of multi-phase lines, the relative location of the faulty line and fault point is determined. The nearest target arc-suppression device is selected, and the compensation injection current value is determined based on its arc-suppression parameters. The compensation current is precisely injected at a suitable electrical node near the fault point, actively reconstructing the zero-sequence current path after the fault. This achieves precise cancellation of residual current at the fault point, rapid on-site elimination of single-phase grounding faults, and reduces the shunting and distortion effects of line impedance on the compensation current. It realizes the goal of precise tracking and effective compensation of the compensation current, thereby achieving precise suppression and intelligent management of single-phase grounding faults. It achieves millisecond-level, near-zero residual current arc-suppression effects, effectively complementing centralized compensation within the station. This ensures stable bus voltage without affecting the operation of other normal lines, thus solving the technical problem of poor performance of centralized compensation methods for single-phase grounding faults in related technologies.

[0063] As an optional embodiment, the compensation injection current value is determined based on the arc suppression parameters corresponding to the target arc suppression device, including: when the arc suppression parameters include equivalent impedance and line injection voltage, obtaining the angular frequency corresponding to the predetermined power frequency, the inductance value of the arc suppression coil, the total admittance corresponding to the multi-phase line, and the upstream zero-sequence impedance upstream of the fault point, wherein the total admittance is determined based on the capacitance to ground and conductance to ground of the healthy phase line and the capacitance to ground and conductance of the line upstream of the fault point in the faulty line; and the compensation injection current value is determined based on the equivalent impedance, line injection voltage, angular frequency, inductance value, total admittance, and upstream zero-sequence impedance.

[0064] Among them, equivalent impedance refers to the equivalent impedance parameter of the active arc suppression device itself. It is the core electrical parameter for calculating the compensation injection current value and can provide the impedance basis of the device itself for current calculation. For example, the equivalent impedance of a certain active arc suppression device is 5Ω.

[0065] Among them, the line injection voltage refers to the output voltage when the active arc suppression device injects compensation current into the faulty line. It is the basic electrical parameter for calculating the compensation current and can provide core data in the voltage dimension for current calculation. For example, the injection voltage of the active arc suppression device into the faulty line is 10kV.

[0066] Among them, the predetermined power frequency refers to the power frequency specified for the operation of the distribution network. It is the basic parameter for determining the angular frequency and can provide a unified frequency standard for the calculation of electrical parameters. For example, the predetermined power frequency is 50Hz.

[0067] Among them, angular frequency refers to the frequency of electrical angle change obtained by converting the predetermined power frequency. It is the key to calculating parameters such as inductive impedance. It can convert power frequency parameters into parameter forms suitable for electrical formula calculation. For example, the angular frequency corresponding to a 50Hz power frequency is 100πrad / s.

[0068] Among them, the inductance value refers to the inductance value of the arc suppression coil itself. It is the core parameter for calculating the inductive compensation capability of the arc suppression coil and can reflect the ability of the arc suppression coil to provide inductive current. For example, the inductance value of a certain arc suppression coil is 2H.

[0069] Among them, total admittance refers to the sum of the admittance to ground of the healthy phase line and the upstream of the fault point of the fault line in the distribution network. It is a comprehensive parameter that reflects the line's capacitive and conductive characteristics to ground and can provide a basis for the line's electrical characteristics to ground for the calculation of compensation current. For example, the total admittance of the system under a certain fault scenario is 0.02S.

[0070] Among them, the upstream zero-sequence impedance refers to the zero-sequence impedance of the line from the fault point to the beginning of the line. It is a parameter that reflects the zero-sequence electrical characteristics of the line upstream of the fault point and can accurately reflect the impedance influence of the line upstream of the fault point. For example, the upstream zero-sequence impedance of the fault point is 8Ω.

[0071] Among them, a healthy phase line refers to a multi-phase line that has not experienced a single-phase ground fault. It is the line part of the distribution network that transmits power normally and can provide the ground parameters of the non-faulty line for the calculation of total admittance. For example, when phase A is faulty, phase B and phase C are healthy phase lines.

[0072] Among them, the capacitance to ground refers to the capacitance formed between the line and the ground. It is an inherent electrical parameter of the line and can reflect the capacitive current characteristics of the line to ground. For example, the capacitance to ground of cable lines is much larger than that of overhead lines.

[0073] Among them, the conductance to ground refers to the conductance between the line and the ground. It is an inherent electrical parameter of the line and can reflect the conductance current characteristics of the line to ground. For example, aging of the line insulation will lead to an increase in the conductance to ground.

[0074] In this embodiment, the equivalent impedance of the target arc-suppression device and the line injection voltage are used as the basic arc-suppression parameters. First, the angular frequency corresponding to the predetermined power frequency of the distribution network, the inductance value of the arc-suppression coil, and the total system admittance determined by the capacitance and conductance to ground of the healthy phase lines and the capacitance and conductance to ground of the upstream line of the fault point in the faulty line are obtained. Simultaneously, the upstream zero-sequence impedance of the fault point is obtained. Finally, by combining all the above electrical parameters, the compensation injection current value injected into the faulty line is determined. This method establishes a basic parameter system for calculating the compensation injection current value, clarifying the basis for determining the various electrical parameters required for the core calculation and the total admittance.

[0075] This embodiment clarifies the basic parameter selection rules for calculating the compensation injection current value. It incorporates the ground capacitance and conductance of the healthy phase line and the upstream line of the fault point into the calculation basis of the total admittance, so that the total admittance can truly reflect the electrical characteristics of the system to ground under the fault scenario. This avoids calculation deviations caused by one-sided parameter selection and lays a parameter foundation that fits the actual fault conditions of the distribution network for the subsequent accurate calculation of the current value. At the same time, the selected parameters cover four dimensions: the characteristics of the device itself, the characteristics of the arc suppression coil, the zero-sequence characteristics of the line, and the characteristics of the system to ground. This achieves comprehensive coverage of electrical factors related to fault arc suppression, so that the calculated compensation injection current value can initially match the residual current compensation requirements of the fault point, and solves the problem of incomplete consideration of traditional compensation current calculation parameters.

[0076] As an optional embodiment, the compensation injection current value is determined based on the equivalent impedance, line injection voltage, angular frequency, inductance value, total admittance, and upstream zero-sequence impedance, including: obtaining the downstream zero-sequence impedance downstream of the fault point; and determining the compensation injection current value based on the equivalent impedance, line injection voltage, angular frequency, inductance value, total admittance, upstream zero-sequence impedance, and downstream zero-sequence impedance.

[0077] Among them, the downstream zero-sequence impedance refers to the zero-sequence impedance of the line from the fault point to the end of the line. It is a parameter that reflects the zero-sequence electrical characteristics of the line downstream of the fault point and can accurately reflect the impedance influence of the line downstream of the fault point. For example, the downstream zero-sequence impedance of the fault point is 5Ω.

[0078] In this embodiment, in addition to the equivalent impedance, line injection voltage, angular frequency, inductance, total admittance, and upstream zero-sequence impedance, the downstream zero-sequence impedance of the fault point is additionally obtained. Finally, by combining all the above parameters, the compensation injection current value is determined. In this way, the line zero-sequence impedance parameter downstream of the fault point is added to the basic parameter system, thus improving the coverage of the zero-sequence impedance dimension parameter of the faulty line.

[0079] This embodiment adds the downstream zero-sequence impedance of the fault point to the basic calculation parameters, so that the current value calculation fully considers the influence of the zero-sequence impedance of the entire fault line upstream and downstream of the fault point. This makes up for the problem of incomplete coverage of line characteristics caused by only considering the upstream zero-sequence impedance, and makes the calculation parameters more consistent with the actual electrical layout of the fault line. For the scenario where the target arc suppression device is located after the fault point, the downstream zero-sequence impedance is a key factor affecting the compensation current transmission and arc suppression effect. The addition of this parameter allows the calculation of the compensation injection current value to be accurately adapted to this fault scenario, improves the matching degree between the current calculation result and the actual arc suppression requirements, and avoids the problem of insufficient or excessive compensation current caused by ignoring the downstream line impedance.

[0080] As an optional embodiment, the compensation injection current value is determined based on the equivalent impedance, line injection voltage, angular frequency, inductance value, total admittance, and upstream zero-sequence impedance, including: determining a first term based on the inductance and angular frequency; obtaining a first sum based on the sum of the reciprocal of the first term and the total admittance, and determining the sum of the upstream zero-sequence impedance, downstream zero-sequence impedance, and equivalent impedance to obtain a second sum; determining the product of the first sum and the line injection voltage to obtain a first product, and determining the product of the first term and the second sum to obtain a second product, and determining the product of the total admittance and the second sum to obtain a third product; determining a predetermined coefficient, the sum of the second product, and the third product to obtain a fourth sum; and determining the ratio of the first product to the fourth sum to obtain the compensation injection current value.

[0081] The first item refers to the intermediate calculation quantity derived from the inductance value and angular frequency of the arc suppression coil. It is the basic intermediate parameter for subsequent current calculations, which can transform the combined influence of inductance and angular frequency into a single calculation quantity, simplifying subsequent formula calculations.

[0082] Among them, the first sum refers to the intermediate calculated quantity obtained by adding the reciprocal of the first term to the total admittance. It can integrate the combined influence of the line admittance and the inductive characteristics of the arc suppression coil, and provide integrated parameter basis for current calculation.

[0083] The second term refers to the intermediate calculation quantity obtained by adding the upstream zero-sequence impedance, the downstream zero-sequence impedance, and the equivalent impedance. It can integrate the comprehensive impact of the impedance of the upstream and downstream lines and devices at the fault point, and simplify the calculation of the impedance dimension.

[0084] The first product refers to the intermediate calculation quantity obtained by multiplying the first sum by the line injection voltage. It can combine the voltage with the comprehensive characteristics of the line and the arc suppression coil, and provide voltage-related calculation basis for the final current calculation.

[0085] The second product, which is the intermediate calculation result obtained by multiplying the first term by the second sum, integrates the inductive characteristics of the arc suppression coil and the combined effects of various impedances. It is the core intermediate data for current calculation.

[0086] The third product, which is the intermediate calculation obtained by multiplying the total admittance by the second product, can integrate the combined effects of line-to-ground admittance and various impedances, and improve the parameter dimensions of current calculation.

[0087] Among them, the predetermined coefficient refers to the calculation coefficient preset according to the actual operating conditions of the distribution network. It can adapt to the operating characteristics of different distribution networks and make the current calculation results more in line with the actual system requirements. For example, the predetermined coefficient for the fault current calculation of a certain distribution network is 1.

[0088] Among them, the fourth sum refers to the intermediate calculation quantity obtained by adding the predetermined coefficient, the second product and the third product. It can integrate the multiple influences of the preset coefficient, the characteristics of the arc suppression coil, the impedance of the line and device, and the line admittance, and provide a comprehensive parameter basis for the final current calculation.

[0089] Among them, the ratio refers to the value obtained by dividing two calculated quantities. It is the final calculation method to determine the compensation injection current value and can transform the comprehensive influence of various intermediate calculated quantities into a specific current value.

[0090] In this embodiment, the first term is calculated based on the inductance value and angular frequency. Then, the first sum (reciprocal of the first term + total admittance) and the second sum (upstream zero-sequence impedance + downstream zero-sequence impedance + equivalent impedance) are calculated separately. Subsequently, the first product (first sum × line injection voltage), the second product (first term × second sum), and the third product (total admittance × second sum) are obtained through multiplication operations, and the fourth sum (predetermined coefficient + second product + third product) is calculated. Finally, the final compensation injection current value is obtained by calculating the ratio of the first product to the fourth sum. In this way, the complex compensation current calculation formula is broken down into multiple simple arithmetic operations, clarifying the intermediate calculation amount and calculation logic of each step.

[0091] This embodiment breaks down abstract and complex electrical calculation formulas into step-by-step arithmetic operations, transforming multi-dimensional electrical parameters into progressive intermediate calculations. This reduces the operational difficulty and calculation errors caused by directly calculating complex formulas, making the current value calculation process more logical and operable, facilitating algorithm implementation and program writing in practical engineering. Simultaneously, each intermediate calculation integrates one or more types of electrical characteristics, clearly demonstrating the impact of factors such as arc suppression coils, line impedance, device impedance, and system admittance on the compensation current. This facilitates subsequent verification of calculation results and parameter adjustment, improving the accuracy and traceability of the compensation injection current value calculation. Furthermore, the introduction of predetermined coefficients allows the calculation method to adapt to different distribution network operating conditions, enhancing its versatility and practical application value.

[0092] As an optional embodiment, the compensation injection current value is determined based on the equivalent impedance, line injection voltage, angular frequency, inductance value, total admittance, and upstream zero-sequence impedance, including: determining a first term based on the inductance and angular frequency; determining the sum of the first term and the upstream zero-sequence impedance to obtain a fifth sum; determining the sum of the reciprocal of the fifth sum and the total admittance to obtain a sixth sum; determining the product of the sixth sum and the line injection voltage to obtain a fourth product, and determining the product of the sixth sum and the equivalent impedance to obtain a fifth product; determining the sum of the fifth product and a predetermined coefficient to obtain a seventh sum; and determining the ratio of the fourth product to the seventh sum to obtain the compensation injection current value.

[0093] Among them, the fifth term refers to the intermediate calculation quantity obtained by adding the first term to the upstream zero-sequence impedance. It can integrate the inductive characteristics of the arc suppression coil and the influence of the upstream line impedance at the fault point, and is suitable for fault scenario calculations that do not need to consider the downstream zero-sequence impedance.

[0094] Among them, the sixth sum refers to the intermediate calculation quantity obtained by adding the reciprocal of the fifth sum to the total admittance. It can integrate the comprehensive characteristics of the line admittance, the arc suppression coil, and the upstream line, and provide integrated parameters for current calculation in specific fault scenarios.

[0095] Among them, the fourth product refers to the intermediate calculation quantity obtained by multiplying the sixth product by the line injection voltage. It can combine the voltage with the comprehensive characteristics of the line and arc suppression coil under specific scenarios to adapt to the current calculation of the scenario.

[0096] Among them, the fifth product refers to the intermediate calculation quantity obtained by multiplying the sixth product by the equivalent impedance. It can integrate the comprehensive characteristics of a specific scenario with the influence of the device's equivalent impedance and improve the current calculation in that scenario.

[0097] Among them, the seventh sum refers to the intermediate calculation quantity obtained by adding the fifth product to the predetermined coefficient. It can integrate the influence of the preset coefficient, device impedance and the comprehensive characteristics of a specific scenario, and provide a basis for the final current calculation of the scenario.

[0098] In this embodiment, the first term is calculated based on the inductance value and angular frequency. Then, the fifth sum (first term + upstream zero-sequence impedance) and the sixth sum (reciprocal of the fifth sum + total admittance) are calculated. Subsequently, the fourth product (sixth sum × line injection voltage) and the fifth product (sixth sum × equivalent impedance) are obtained through multiplication, and the seventh sum (fifth product + predetermined coefficient) is calculated. Finally, the final compensation injection current value is obtained by calculating the ratio of the fourth product to the seventh sum. This method provides another set of step-by-step calculation logic, adaptable to fault scenarios where the downstream zero-sequence impedance of the fault point does not need to be considered.

[0099] This embodiment provides a step-by-step calculation method adapted to fault scenarios where downstream zero-sequence impedance is not required. It specifically eliminates calculations related to downstream zero-sequence impedance, making the current calculation more closely match the actual scenario where the target arc-suppression device is located before the fault point. This avoids computational redundancy caused by the introduction of useless parameters and improves computational efficiency in this scenario. Simultaneously, this calculation method also employs a step-by-step intermediate calculation design, continuing the advantages of simple operation and strong traceability, facilitating engineering implementation and verification. Furthermore, the fifth and sixth intermediate calculations accurately integrate the comprehensive electrical characteristics of the arc-suppression coil and the upstream line of the fault point, allowing the calculation results to highly match the residual current compensation requirements of the fault point in this scenario. In addition, this method complements the calculation logic of optional embodiment 3, adapting to two core scenarios before and after the fault point for the target arc-suppression device, making the entire compensation current calculation system more complete and scenario-adaptable.

[0100] As an optional embodiment, after determining the compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device, the method further includes: controlling the target arc suppression device to inject the compensation injection current value into the faulty line and performing a ground residual current cancellation operation to suppress the residual current at the fault point.

[0101] Among them, residual current to ground refers to the residual fault current flowing to the ground from the fault point after a single-phase ground fault occurs. It is the core target of arc suppression operation and can reflect the degree of fault at the fault point. For example, the residual current to ground at the fault point is 10A when there is no compensation.

[0102] Among them, residual current suppression refers to the arc-extinguishing operation of canceling the residual current to ground at the fault point by injecting compensation current. It is the core objective of arc extinguishing in distribution network faults and can reduce the residual current at the fault point to a safe range, such as suppressing the residual current to ground at the fault point to below 0.5A.

[0103] In this embodiment, after determining the compensation injection current value through any of the aforementioned embodiments, a subsequent execution step is added. Specifically, the control system issues a command to control the selected target arc-extinguishing device to precisely inject the compensation injection current value into the faulty line, actively performing the cancellation operation of the residual current to ground, ultimately suppressing the residual current at the fault point. This method completes a closed loop from calculating the compensation injection current value to the actual arc-extinguishing operation, transforming the theoretical calculation results into actual fault arc-extinguishing actions.

[0104] This embodiment, based on the calculation of the compensation injection current value, adds the execution steps of actual injection and residual current suppression, breaking through the limitations of traditional methods that only remain at the theoretical calculation level. It realizes a closed loop of arc suppression, including parameter calculation, current injection, and residual current cancellation, so that the accurate calculation results can be effectively translated into actual arc suppression effects. At the same time, the target arc suppression device accurately injects the calculated compensation injection current value into the faulty line, which can specifically cancel the residual current to ground at the fault point and suppress the residual current at the fault point to a safe range. This achieves accurate on-site arc suppression of single-phase ground faults and solves the problems of large compensation current transmission loss and poor residual current cancellation effect in traditional centralized compensation. In addition, by controlling the target arc suppression device to perform the injection operation independently, the precise allocation of arc suppression resources is realized, avoiding the waste of resources in multi-device linkage. Moreover, the on-site arc suppression method can effectively reduce the impact of the fault on the bus voltage and other healthy lines, ensuring the stable operation of the entire distribution network.

[0105] Based on the above embodiments and optional embodiments, an optional implementation method is provided, which is described in detail below.

[0106] An optional embodiment of the present invention provides a distributed active arc suppression system for single-phase grounding faults, which can achieve precise suppression and intelligent management of single-phase grounding faults. Figure 2 This is a circuit diagram provided by an optional embodiment of the present invention, showing that the fault point occurs downstream of the zero-sequence current transformer and upstream of the active arc suppression device. Figure 3 This is an equivalent zero-sequence circuit diagram provided by an optional embodiment of the present invention, showing that the fault point occurs downstream of the zero-sequence current transformer and upstream of the active arc suppression device. Figure 4 This is a circuit diagram of an active arc suppression device and an arc suppression coil installed at the neutral point, provided by an optional embodiment of the present invention. Figure 5 This is an equivalent zero-sequence circuit diagram of an active arc suppression device and an arc suppression coil installed at the neutral point, provided by an optional embodiment of the present invention. Figure 6 This is a current relationship diagram between the active arc suppression device and the arc suppression coil installed at the neutral point, provided by an optional embodiment of the present invention. Figure 7 This is a circuit diagram provided by an optional embodiment of the present invention, showing that the fault point occurs downstream of the zero-sequence current transformer and downstream of the active arc suppression device. Figure 8 This is an equivalent zero-sequence circuit diagram provided by an optional embodiment of the present invention, where the fault point occurs downstream of the zero-sequence current transformer and downstream of the active arc suppression device.

[0107] The active arc suppression system provided in the optional embodiment of the present invention includes an arc suppression coil, a zero-sequence current transformer and an active arc suppression device. Each phase line is equipped with one zero-sequence current transformer and at least one active arc suppression device. The arc suppression coil is led out and grounded at the neutral point of the power distribution system.

[0108] Furthermore, a zero-sequence current transformer is installed at the beginning of each phase line, and at least one active arc suppression device is installed at a preset position at a non-beginning end of each phase line.

[0109] Furthermore, zero-sequence current transformers are installed at the beginning of each phase of the line, and several active arc-suppression devices are evenly distributed at different locations along the line. Based on the measurements from the zero-sequence current transformers, the active arc-suppression device closest to the fault point on the line is triggered. Even further, the current injected into the line by the triggered active arc-suppression device... (same as above based on inductance) With angular frequency Rate, determine the first item Based on the reciprocal of the first term and the total admittance The sum of these sums is used to obtain the first sum and determine the upstream zero-sequence impedance. Downstream zero-sequence impedance equivalent impedance The sum of the first and second sums is obtained; the relationship between the first and second sums and the line injection voltage is determined. The product of the first term and the second sum is used to obtain the first product, and the product of the first term and the second sum is used to obtain the second product, and the total admittance is determined. The product of the first product and the second product is used to obtain the third product; the sum of the predetermined coefficient (e.g., 1), the second product, and the third product is determined to obtain the fourth product; the ratio of the first product to the fourth product is determined to obtain the compensation injection current value. ):

[0110]

[0111] In the formula, The voltage injected into the circuit by the triggered active arc suppression device. It is the angular frequency corresponding to the power frequency. It is the inductance of the arc suppression coil; It represents the sum of the capacitance to ground and conductance to ground of the healthy phase line and the capacitance to ground and conductance of the upstream line of the fault point; This represents the zero-sequence impedance of the line upstream of the fault point. This represents the zero-sequence impedance of the line downstream of the fault point. This is the equivalent impedance of the active arc suppression device.

[0112] Furthermore, zero-sequence current transformers are installed at the beginning of each phase of the line, and several active arc-suppression devices are evenly distributed at different locations along the line. Based on the measurements from the zero-sequence current transformers, the active arc-suppression device closest to the fault point on the line is triggered. Even further, the current injected into the line by the triggered active arc-suppression device... (same as above based on inductance) With angular frequency Determine the first item Determine the first term and its relationship with the upstream zero-sequence impedance. The sum of the first and second parts yields the fifth sum; based on the reciprocal of the fifth sum and the total admittance... The sum of the first and second sums is used to obtain the sixth sum; the relationship between the sixth sum and the line injection voltage is then determined. The product of these products yields the fourth product, and the sixth product is determined in relation to the equivalent impedance. The product of the first product and the second product is used to obtain the fifth product; the sum of the fifth product and a predetermined coefficient (such as 1) is determined to obtain the seventh sum; the ratio of the fourth product to the seventh sum is determined to obtain the compensation injection current value. ):

[0113]

[0114] In the formula, The voltage injected into the line by the triggered active arc suppression device. It is the angular frequency corresponding to the power frequency. It is the inductance of the arc suppression coil; It represents the sum of the capacitance to ground and conductance to ground of the healthy phase line and the capacitance to ground and conductance of the upstream line of the fault point; This represents the zero-sequence impedance of the line upstream of the fault point. This is the equivalent impedance of the active arc suppression device.

[0115] Specifically, as an optional embodiment, the following example is provided:

[0116] This embodiment provides a distributed active arc suppression system for single-phase ground faults, including an arc suppression coil, a zero-sequence current transformer, and active arc suppression devices. Each phase line is equipped with one zero-sequence current transformer and several active arc suppression devices. The arc suppression coil is led out and grounded at the neutral point of the power distribution system. On each phase line, the zero-sequence current transformer is installed at the beginning of the line, and several active arc suppression devices are evenly distributed at different locations on the line.

[0117] When a ground fault occurs in a certain phase of the line, the zero-sequence current transformer at the beginning of the line measures that the zero-sequence current value at the beginning of the line exceeds the threshold. After the fault location is determined by existing technology, the nearest active arc suppression device after the fault point is triggered, which works in conjunction with the neutral point grounding arc suppression coil to provide compensation current.

[0118] This situation is equivalent to the fault occurring downstream of the zero-sequence current transformer and upstream of the active arc suppression device. Since the zero-sequence current transformer (CT) is installed at the beginning of the faulty line, the zero-sequence component of the fault current must flow through the beginning of the line to form a loop, thus covering most of the line area. The corresponding circuit diagram is as follows: Figure 2 As shown, the equivalent circuit diagram is as follows: Figure 3 As shown. Among them, This represents the sum of the capacitance to ground and conductance to ground of the healthy phase line, as well as the capacitance to ground and conductance of the upstream line of the fault point. , where C A_up C represents the equivalent capacitance to ground of phase A from the grounding point to the neutral point. B Represents the equivalent capacitance to ground of phase B line, C C This represents the equivalent capacitance to ground of phase C. Similarly, G... A_UP G represents the equivalent conductance to ground between the short-circuit point of phase A and the neutral point. B G represents the equivalent conductance of B relative to ground. C This represents the equivalent conductance (admittance) of C relative to ground, ignoring the line-to-ground parameters between the fault point and the active arc suppression device (this parameter is relative to...). Very small); This represents the zero-sequence impedance of the line upstream of the fault point. This represents the zero-sequence impedance of the line upstream of the fault point. According to the equivalent zero-sequence circuit, we have:

[0119]

[0120] In the formula, Represents zero-sequence voltage. and These represent the injected voltage and current from the triggered active arc suppression device into the circuit, respectively. The equivalent impedance of the active arc suppression device. This represents the zero-sequence impedance of the line downstream of the fault point. It is the residual current at the fault point. It is the angular frequency corresponding to the power frequency. It is the inductance of the arc suppression coil; It is the inductive current compensated by the arc suppression coil. It is the sum of the capacitive current and the conductive current to ground. This represents the zero-sequence impedance of the line upstream of the fault point. Represents zero-sequence voltage. This represents the short-circuit voltage. From this formula, we can obtain:

[0121]

[0122] in, This indicates the grounding resistance.

[0123] Under ideal conditions, if the active arc suppression device injects current to compensate for all residual current to ground, the above equation simplifies to:

[0124]

[0125] As can be seen from the above formula, The larger the current, the smaller the current injected by the active arc suppression device, which can achieve a more ideal arc suppression effect. Therefore, the active arc suppression device should be selected downstream of the fault point and closest to the fault point.

[0126] Arc suppression coils can compensate for the ground capacitance current of all healthy lines, significantly reducing the portion of the total current flowing to the fault point from healthy lines, quickly suppressing the rise of the zero-sequence voltage on the bus, and providing a stable basic environment for the entire system. The end-point device has the shortest compensation path, when... When the current is relatively small (close to 0), it can theoretically achieve precise arc suppression with millisecond-level and near-zero residual current, and the fault is quickly cleared on-site without affecting the bus voltage and other lines.

[0127] The following section compares the injected current of the zero-sequence current transformer installed at the beginning of the faulty line and the triggered active arc suppression device located downstream of the fault point with that of the conventional active arc suppression device installed at the neutral point.

[0128] Conventional techniques involve installing an active arc suppression device at the neutral point. If this device is used in parallel with the arc suppression coil to provide compensation current, the circuit diagram and equivalent circuit diagram are as follows: Figure 4 , Figure 5 As shown. When the device injects current. Then, it propagates along the conductor towards the fault point. During this process, a portion of the current is continuously diverted to the ground by the parallel ground capacitance. Therefore, the current in the conductor gradually decreases from the injection point until it reaches the fault point. Simultaneously, due to the presence of series impedance, the voltage along the line also gradually decreases. This comparative experiment uses centralized ground capacitance and centralized line impedance to represent the ground capacitance parameters and the distributed line impedance. Figure 4 , Figure 5 middle, This represents the equivalent line impedance from the neutral point to the fault location. The model represents the equivalent parameters of a three-phase line to ground. It assumes the fault occurs at the end of the line and the three-phase parameters to ground are symmetrical. , Among them, under three-phase equilibrium, C A、 C B、 C C These represent the three-phase equivalent capacitances to ground, with the same value being C0 and G. A、 G B、 G C These represent the three-phase equivalent admittances to ground, with the same value being G0.

[0129]

[0130] A virtual power source for the fault point.

[0131]

[0132]

[0133]

[0134] Combining the above three equations, we have:

[0135]

[0136] In the formula: It is the inductive current compensated by the arc suppression coil. It is the sum of the capacitive current and the conductive current to ground.

[0137] Because the compensation current needs to flow along the entire length of the faulty line to reach the fault point, for faults at the end of long lines, the line impedance... This could lead to a decrease in the compensation effect, and it may not be able to achieve the ultimate performance of the distributed active arc suppression device scheme of the present invention.

[0138] Ideally, if the active arc suppression device injects current to compensate for all residual current to ground, then

[0139]

[0140] The above formula It can be simplified to:

[0141]

[0142] It can be seen that when In smaller cases, the required The difference will be relatively small. If the fault occurs far from the neutral point, the compensation effect will be relatively worse due to the reduced line impedance. This is mainly reflected in the fact that the amplitude and phase of the current injected by the active arc suppression device gradually change with the length of the line as it travels along the line to the fault point. The longer the line, the greater the difference between the compensation current reaching the fault point and the actual required compensation current. For example... Figure 6 As shown,

[0143] In this embodiment, the zero-sequence current transformer is installed at the beginning of the faulty line, and the triggered active arc suppression device is located downstream of the fault point. The path through which the compensation current needs to flow is the arc suppression coil, the line, and the ground path. When an active arc suppression device is installed at the neutral point, the path through which the compensation current needs to flow is the arc suppression coil, the line, and the ground connection. In terms of the triangular network formed by the three elements, this embodiment reduces amplitude loss and phase change.

[0144] Therefore, the present invention can reduce the influence of line transformer impedance on the injected current, is a relatively ideal installation location, and the device can compensate for the line individually, which in turn increases the capacity of the arc suppression device when a single line fails.

[0145] Specifically, as another optional embodiment, the following will be described:

[0146] This embodiment provides a distributed active arc suppression system for single-phase ground faults, including an arc suppression coil, a zero-sequence current transformer, and active arc suppression devices. Each phase line is equipped with one zero-sequence current transformer and several active arc suppression devices. The arc suppression coil is led out and grounded at the neutral point of the power distribution system. On each phase line, the zero-sequence current transformer is installed at the beginning of the line, and several active arc suppression devices are evenly distributed at different locations on the line.

[0147] When a ground fault occurs in a certain phase of the line, the zero-sequence current transformer at the beginning of the line measures that the zero-sequence current value at the beginning of the line exceeds the threshold. After the fault location is determined by existing technology, the active arc suppression device that is closest to the fault point is triggered and works in conjunction with the neutral point grounding arc suppression coil to provide compensation current.

[0148] This situation is equivalent to the fault point occurring downstream of the zero-sequence current transformer, which is also downstream of the active arc suppression device. For example... Figure 7 As shown, assume the fault occurs at the end of phase A, and the fault current flows out of the substation, through the zero-sequence current transformer, upstream of the fault point, and the active arc suppression device, and continues downstream to the fault point to ground. For ease of analysis, the ground admittance parameter is ignored. The capacitance to ground of the non-faulty phase is set as follows: The capacitance to ground of the faulty phase is set as follows: Equivalent circuit such as Figure 8 As shown. This represents the equivalent capacitive current under lumped parameters relative to ground. , This represents the lumped parameters of the line from the system bus to the installation location of the active arc suppression device; This represents the lumped parameters of the line from the installation location of the active arc suppression device to the fault point; It is a transition voltage, representing the voltage to ground at the connection point of the active arc suppression device.

[0149] According to the zero-order equivalent graph, we have:

[0150]

[0151] in, refer to Figure 8 The ground voltage values ​​at the points shown are used here to calculate the transition;

[0152] Right now:

[0153]

[0154] Under ideal conditions, if the active arc suppression device injects current to compensate for all residual current to ground, then the above equation simplifies to:

[0155]

[0156] As can be seen from the above formula, the injection current of the active arc suppression device and upstream line zero-sequence impedance Related to, with The increase, The smaller the value, the better. Therefore, the active arc suppression device closest to the upstream of the fault point can be selected to work together with the neutral point arc suppression coil to complete the fault current compensation.

[0157] The above optional implementation methods can achieve at least the following beneficial effects:

[0158] This invention utilizes an arc-suppression coil and a distributed active arc-suppression device to collaboratively compensate for fault current. The arc-suppression coil provides a basic, fixed (or slowly adjustable) inductive compensation current, while the active arc-suppression device acts as a precision compensator or residual current eliminator. The active arc-suppression device injects compensation current at the most suitable electrical node, actively reconstructing the zero-sequence current path after the fault, thereby achieving precise suppression and intelligent management of single-phase grounding faults. Furthermore, the distributed active compensation device of this invention, deployed at multiple points along the line, can achieve rapid and accurate tracking and cancellation of the ground capacitance current in the area, thus effectively complementing centralized compensation within the substation.

[0159] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0160] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0161] Example 2

[0162] According to an embodiment of the present invention, an apparatus for implementing the above-described method for determining the compensation current of an active arc suppression system is also provided. The apparatus includes: an acquisition module, a first determination module, a second determination module, and a third determination module. The apparatus will be described in detail below.

[0163] The acquisition module is used to acquire the zero-sequence current measurement values ​​corresponding to the multi-phase lines in the active arc suppression system. The active arc suppression system includes an arc suppression coil, zero-sequence current transformers corresponding to the multi-phase lines, and multiple active arc suppression devices. These active arc suppression devices are respectively located at different positions from the beginning of the corresponding lines, the corresponding zero-sequence current transformers are located at the beginning of the corresponding lines, and the arc suppression coils are located between the neutral point and the grounding grid. The first determination module, connected to the acquisition module, is used to determine the faulty line from the multi-phase lines based on the multiple zero-sequence current measurement values, and the relative position of the fault point within the faulty line. The second determination module, connected to the first determination module, is used to determine the target arc suppression device closest to the fault point in the target orientation based on the relative position from the multiple active arc suppression devices. The third determination module, connected to the second determination module, is used to determine the compensation injection current value based on the arc suppression parameters corresponding to the target arc suppression device.

[0164] It should be noted here that the above-mentioned acquisition module, first determination module, second determination module and third determination module correspond to steps S102 to S108 in the method for determining the compensation current of the active arc suppression system. The multiple modules and the corresponding steps are the same in terms of implementation examples and application scenarios, but are not limited to the content disclosed in the above embodiment 1.

[0165] Example 3

[0166] According to another aspect of the present invention, an active arc suppression system is also provided, comprising: an arc suppression coil, a zero-sequence current transformer corresponding to a multi-phase line, and a plurality of active arc suppression devices, wherein the plurality of active arc suppression devices are respectively disposed at different positions at a distance from the beginning of the corresponding line, the corresponding zero-sequence current transformer is disposed at the beginning of the corresponding line, and the arc suppression coil is disposed between the neutral point and the grounding grid.

[0167] Example 4

[0168] According to another aspect of the present invention, an electronic device is also provided, comprising: a processor; and a memory for storing processor-executable instructions, wherein the processor is configured to execute instructions to implement the compensation current determination method for the active arc suppression system described above.

[0169] Example 5

[0170] According to another aspect of the present invention, a computer-readable storage medium is also provided, which, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the compensation current determination method for an active arc suppression system described above.

[0171] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0172] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0173] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0174] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0175] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0176] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0177] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the compensation current of an active arc suppression system, characterized in that, include: The measurement values ​​of zero-sequence current corresponding to the multi-phase lines in the active arc suppression system are obtained. The active arc suppression system includes an arc suppression coil, a zero-sequence current transformer corresponding to the multi-phase lines, and multiple active arc suppression devices. The multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding lines. The corresponding zero-sequence current transformer is set at the beginning of the corresponding lines. The arc suppression coil is set between the neutral point and the grounding grid. Based on multiple zero-sequence current measurements, the faulty line is identified from the multiphase lines, along with the relative position of the fault point within that faulty line. Based on the relative positions, the target arc suppression device that is closest to the fault point at the target location is determined from among multiple active arc suppression devices; The compensation injection current value is determined based on the arc extinguishing parameters corresponding to the target arc extinguishing device.

2. The method according to claim 1, characterized in that, Based on the arc extinguishing parameters corresponding to the target arc extinguishing device, the compensation injection current value is determined, including: When the arc suppression parameters include equivalent impedance and line injection voltage, the angular frequency corresponding to the predetermined power frequency, the inductance value of the arc suppression coil, the total admittance corresponding to the multiphase line, and the upstream zero-sequence impedance upstream of the fault point are obtained. The total admittance is determined based on the capacitance to ground and conductance to ground of the healthy phase line and the capacitance to ground and conductance of the line upstream of the fault point in the fault line. The compensation injection current value is determined based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance.

3. The method according to claim 2, characterized in that, Based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance, the compensation injection current value is determined, including: Obtain the downstream zero-sequence impedance downstream of the fault point; The compensation injection current value is determined based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, the upstream zero-sequence impedance, and the downstream zero-sequence impedance.

4. The method according to claim 3, characterized in that, Based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance, the compensation injection current value is determined, including: Based on the aforementioned inductance and angular frequency, determine the first item; Based on the sum of the reciprocal of the first term and the total admittance, a first sum is obtained, and the sum of the upstream zero-sequence impedance, the downstream zero-sequence impedance, and the equivalent impedance is determined to obtain a second sum; The product of the first sum and the line injection voltage is determined to obtain the first product; the product of the first sum and the second sum is determined to obtain the second product; and the product of the total admittance and the second sum is determined to obtain the third product. The fourth sum is obtained by determining the predetermined coefficients, the second product, and the sum of the third product; The ratio of the first product to the fourth sum is determined to obtain the compensation injection current value.

5. The method according to claim 2, characterized in that, Based on the equivalent impedance, the line injection voltage, the angular frequency, the inductance value, the total admittance, and the upstream zero-sequence impedance, the compensation injection current value is determined, including: Based on the aforementioned inductance and angular frequency, determine the first item; The sum of the first term and the upstream zero-sequence impedance is determined to obtain the fifth sum; The sixth sum is obtained by summing the reciprocal of the fifth sum and the total admittance; The product of the sixth sum and the line injection voltage is determined to obtain the fourth product, and the product of the sixth sum and the equivalent impedance is determined to obtain the fifth product; The sum of the fifth product and the predetermined coefficients is determined to obtain the seventh sum; The ratio of the fourth product to the seventh sum is determined to obtain the compensation injection current value.

6. The method according to any one of claims 1 to 5, characterized in that, After determining the compensation injection current value based on the arc extinguishing parameters corresponding to the target arc extinguishing device, the process further includes: The target arc extinguishing device is controlled to inject the compensation injection current value into the faulty line to perform a ground residual current cancellation operation, thereby suppressing the residual current at the fault point.

7. An active arc suppression system, characterized in that, include: An arc suppression coil, a zero-sequence current transformer corresponding to a multi-phase line, and multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding line. The corresponding zero-sequence current transformer is set at the beginning of the corresponding line, and the arc suppression coil is set between the neutral point and the grounding grid.

8. A compensation current determination device for an active arc suppression system, characterized in that, include: The acquisition module is used to acquire the zero-sequence current measurement values ​​corresponding to the multi-phase lines in the active arc suppression system. The active arc suppression system includes an arc suppression coil, a zero-sequence current transformer corresponding to the multi-phase lines, and multiple active arc suppression devices. The multiple active arc suppression devices are respectively set at different positions from the beginning of the corresponding lines. The corresponding zero-sequence current transformer is set at the beginning of the corresponding lines. The arc suppression coil is set between the neutral point and the grounding grid. The first determining module is used to determine the faulty line from the multiphase lines based on multiple zero-sequence current measurement values, and the relative position of the fault point in the faulty line. The second determining module is used to determine, based on the relative position, the target arc extinguishing device that is closest to the fault point at the target orientation from among multiple active arc extinguishing devices; The third determining module is used to determine the compensation injection current value based on the arc extinguishing parameters corresponding to the target arc extinguishing device.

9. An electronic device, characterized in that, include: processor; Memory used to store the processor's executable instructions; The processor is configured to execute the instructions to implement the method for determining the compensation current of the active arc suppression system as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, When the instructions in the computer-readable storage medium are executed by the processor of the electronic device, the electronic device is able to perform the compensation current determination method for the active arc suppression system as described in any one of claims 1 to 6.

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