A single-circuit fault protection method and system for an arc suppression coil grounding system

Abstract

This disclosure relates to a method and system for protecting a single-circuit line from repeated grounding faults in an arc suppression coil grounding system. The method involves determining whether a grounding fault has occurred on the corresponding line based on the negative-sequence measured impedance angle or negative-sequence measured admittance angle of the line in the arc suppression coil grounding system. The system is used to execute the above method. This disclosure can protect against repeated grounding faults at two points on a single circuit, and is unaffected by factors such as the location of the fault point and transition resistance. It also has the advantages of strong anti-interference ability, stability, applicability, and high sensitivity.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of power grid fault protection, in particular to a single-loop fault restoration protection method and system for arc suppression coil grounding system. BACKGROUND

[0002] With the increasing demand for electricity, the structure of the power grid is increasingly complex and large, and the requirement for power supply reliability is also increasing. The multiple faults of distribution lines are single-phase grounding faults, and single-phase grounding faults can develop into other multiple faults. Therefore, in order to ensure the safe operation of the power system, appropriate grounding protection needs to be set. Multiple single-phase grounding faults may occur simultaneously under extreme conditions such as typhoon, and the types are various, so simple grounding protection is difficult to apply.

[0003] The arc suppression coil grounding system is a compensation device for a small current grounding system. When a single-phase grounding fault occurs in the power grid, the arc suppression coil generates inductive current to compensate for the grounding capacitance current, so that the current through the grounding point is lower than the current value required to generate intermittent arc or maintain stable arc, thereby eliminating the arc at the grounding point.

[0004] The arc suppression coil grounding system usually includes a bus and multiple loops connected to the bus. Accurate positioning of the fault loop is the key to fault protection of the arc suppression coil grounding system. In the prior art, the zero sequence current method is usually used to determine the fault loop. Specifically, the method is based on the difference in the direction of transient zero sequence current between the fault line and the non-fault line. This method is for the case of same-phase grounding fault of two different loops, and is not applicable to the case of two-point different-phase grounding fault of the same loop.

[0005] Another way is to use single-phase grounding simple fault zero sequence overcurrent protection. This method can effectively act on the section of the line between the two fault points of the same loop, but for the section of the line between the first fault point and the bus, the zero sequence current of this section is small, and the protection distance problem is prone to occur.

[0006] In addition, in the prior art, the bus zero sequence voltage and the zero sequence voltage of each loop are collected in real time, and the amplitude and phase relationship of the two are compared to determine the two-point successive grounding fault line selection, but this method can still only be used for line selection of two-point grounding fault of different loops, and the sensitivity of this method is low.

[0007] In summary, there is no effective fault protection method for the two-point different-phase grounding multiple fault situation in the same loop of the arc suppression coil grounding system in the prior art, and fast fault line selection protection cannot be achieved. SUMMARY

[0008] To address the problems existing in the prior art, the present disclosure aims to provide a method and system for protecting a single-circuit grounding system with repeated faults. This disclosure can protect against repeated faults caused by two-point out-of-phase grounding on a single circuit, and is unaffected by factors such as the location of the fault point or transition resistance. It also boasts advantages such as strong anti-interference capability, stability, applicability, and high sensitivity.

[0009] The present disclosure describes a single-circuit fault protection method for an arc suppression coil grounding system, which determines whether a grounding fault has occurred on the corresponding line based on the negative sequence measured impedance angle or negative sequence measured admittance angle of the line in the arc suppression coil grounding system.

[0010] Preferably, the single-circuit fault protection method includes the following steps:

[0011] Obtain the negative sequence impedance angle of each line in the arc suppression coil grounding system under normal operating conditions, denoted as the normal negative sequence impedance angle θ. set ;

[0012] Obtain the negative sequence measured impedance angle θ of a line that may experience a ground fault. k ;

[0013] Calculate the negative sequence measurement impedance angle θ k With normal negative sequence impedance angle θ set The impedance angle difference is denoted as Δθ;

[0014] Determine whether the impedance angle difference value Δθ belongs to the preset impedance angle difference value range C. θ If so, it is determined that a ground fault has occurred on the line; otherwise, it is determined that no ground fault has occurred on the line.

[0015] Alternatively, obtain the negative sequence admittance angle of each line under normal operating conditions of the arc suppression coil grounding system, and record it as the normal negative sequence admittance angle.

[0016] Obtain the negative sequence measurement admittance angle of a line that may experience a ground fault.

[0017] Calculate the negative-order measurement admittance angle With normal negative order admittance angle The difference in admittance angle is denoted as

[0018] Determine the admittance angle difference value Does it fall within the preset admittance angle difference range? If so, it is determined that a grounding fault has occurred on the line; otherwise, it is determined that no grounding fault has occurred on the line.

[0019] Preferably, the line that may experience a grounding fault is determined through the following steps:

[0020] Obtain the negative sequence current setting value of the arc suppression coil grounding system

[0021] Obtain the negative sequence current at the beginning of each line.

[0022] Determine the negative sequence current at the first end Is it greater than the negative sequence current setting value? If so, it is determined that the corresponding line may have a grounding fault; otherwise, it is determined that the line is operating normally.

[0023] Preferably, the negative sequence measured impedance angle θ of the line that may experience a ground fault k Calculate using the following steps:

[0024] Obtain the negative sequence voltage of the line that may have a ground fault.

[0025] Calculate the negative sequence measurement impedance angle θ using the following formula. k :

[0026]

[0027] The negative sequence measured admittance angle of the line that may be subject to a ground fault Calculate using the following steps:

[0028] Obtain the negative sequence voltage of the line that may have a ground fault.

[0029] Calculate the negative-sequence measured admittance angle using the following formula.

[0030]

[0031] Preferably, the negative sequence current setting value is calculated according to the following formula:

[0032]

[0033] Where, k k Represents the reliability coefficient. This indicates the negative sequence current generated on the faulty line when a single-phase ground fault occurs on another feeder.

[0034] Preferably, the impedance angle difference range C θ = [-180°, -90°]; the admittance angle difference range

[0035] This disclosure discloses a single-circuit fault protection system for an arc suppression coil grounding system, comprising:

[0036] The acquisition module is used to acquire the negative sequence measured impedance angle or negative sequence measured admittance angle of the line in the arc suppression coil grounding system;

[0037] The judgment module is used to determine whether a grounding fault has occurred in the corresponding line based on the obtained negative sequence measured impedance angle or negative sequence measured admittance angle.

[0038] This disclosure discloses a computer device including a processor and a memory connected by a signal. The memory stores at least one instruction or at least one program. When the at least one instruction or at least one program is loaded by the processor, it executes the single-circuit fault protection method for an arc suppression coil grounding system as described above.

[0039] This disclosure discloses a computer-readable storage medium storing at least one instruction or at least one program, which, when loaded by a processor, executes the single-circuit fault protection method for an arc suppression coil grounding system as described above.

[0040] The single-circuit fault protection method and system for an arc suppression coil grounding system disclosed herein have the advantages of being able to calculate the negative sequence impedance or admittance by acquiring the negative sequence current and negative sequence voltage at the beginning of the line, thereby obtaining the negative sequence impedance angle or admittance angle, and identifying the faulty line to form protection. This disclosure can protect against single-circuit two-point out-of-phase grounding faults, and only requires negative sequence information of the line to identify the faulty circuit. It requires less information acquisition and communication, has low requirements for equipment synchronization, and is easy to apply. Furthermore, the method can still respond to changes in the two-point grounding position, is unaffected by factors such as fault location and transition resistance, and is also effective when two points are grounded at the same point. It has the advantages of strong anti-interference capability, stability, applicability, and high sensitivity. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the judgment process of the single-circuit fault protection method for the arc suppression coil grounding system described in this embodiment.

[0042] Figure 2 This is a schematic diagram of the two-point grounding fault reconstruction structure of the arc suppression coil grounding system described in this embodiment;

[0043] Figure 3 yes Figure 1 The corresponding negative sequence network diagram for a two-phase ground fault;

[0044] Figure 4 This is the negative sequence measurement impedance angle distribution diagram described in this embodiment;

[0045] Figure 5 This is a schematic diagram of the power distribution network simulation model structure described in this embodiment;

[0046] Figure 6 This is a schematic diagram of the structure of the computer device described in this embodiment.

[0047] Explanation of reference numerals in the attached diagram: T0 - grounding transformer, T1 - main transformer, 101 - processor, 102 - memory. Detailed Implementation

[0048] like Figure 1 As shown, the single-circuit fault protection method for an arc suppression coil grounding system disclosed in this disclosure determines whether a grounding fault has occurred on the corresponding line based on the negative sequence measured impedance angle or negative sequence measured admittance angle of the line in the arc suppression coil grounding system. Specifically, the negative sequence measured impedance angle values ​​of the faulty line and the non-faulty line show a significant difference. The principle is as follows: Figure 2 The diagram shows a 10kV arc suppression coil grounding system. In the diagram, T0 is the grounding transformer, T1 is the system-side main transformer, and L... i (i = 1, 2...n) represent the lengths of each feeder line. Feeder L1 experiences two-point out-of-phase grounding faults simultaneously: point f1 (phase B) is grounded, and point f2 (phase C) is grounded. R f1 R is the grounding transition resistance at point f1. f2 For the grounding transition resistance at point f2, l f1 l is the distance from the busbar to the first fault point f1. f2 Z is the distance from the busbar to the second fault point f2. loadi (i = 1, 2, ..., n) represents the load of the i-th feeder, and a negative sequence network is used for analysis. Figure 2 .

[0049] Figure 3 for Figure 2 The negative sequence network for a single-circuit two-phase ground fault in a grounded arc suppression coil system, taking the negative sequence impedance angle measurement as an example. Figure 3 In and The equivalent sources of the negative-sequence network are respectively calculated as follows:

[0050]

[0051]

[0052] In the formula, and The zero-sequence currents at fault points f1 and f2 can be obtained from the composite sequence network diagram. 1(2) Y 2(2) Y 12(2) These represent the self-admittance at point f1, the self-admittance at point f2, and the mutual admittance between points f1 and f2 in the negative-order network, respectively, where r = e 120°From this, the negative sequence voltage and current information at the beginning of the faulty line can be obtained, and the negative sequence voltage of the bus is:

[0053]

[0054] In the formula, z2 is the negative sequence impedance per unit length of the line, and l 1-1 Y is the distance from the busbar to the first fault point. d1(2) C1 is the point-to-ground negative sequence total admittance, C2 is the line-to-ground negative sequence capacitance per unit length, and ω is the angular frequency.

[0055] The negative sequence current at the beginning of the faulty line is:

[0056]

[0057] The negative sequence current at the beginning of the i-th non-faulty line is:

[0058]

[0059] Using the negative sequence voltage and negative sequence current information at the beginning of the line, the negative sequence measured impedance of each line can be obtained when a two-phase ground fault occurs on a single-circuit line. The negative sequence measured impedance of the faulted line is:

[0060]

[0061] For non-faulty lines, the measured impedance is:

[0062]

[0063] In the formula, l i Let be the length of the i-th line.

[0064] For non-faulty lines, the negative sequence measured impedance is the sum of the line impedance and the load impedance. Since the negative sequence impedance of the line is very small relative to the load impedance, it can be ignored. That is, the negative sequence measured impedance can be considered as the load impedance. The load is generally weakly inductive, that is, the phase is approximately between 0° and 45°.

[0065] For a faulty line, its negative sequence measured impedance is approximately the system negative sequence impedance. The system negative sequence impedance is mainly the equivalent impedance of the main transformer, which is strongly inductive and has a phase of approximately 90°. However, since the direction of outflow from the busbar is defined as the positive direction, the phase of the measured impedance of the faulty line should be -90°.

[0066] Considering a certain margin, the negative sequence impedance angle of the faulty line can be taken as -90°±5°, that is...

[0067] argZ cL1(2) ∈(-85°,-95°);

[0068] For non-faulty lines, the negative sequence measured impedance angle is:

[0069] argZ cLi(2) ∈(0°,45°).

[0070] Draw the negative sequence impedance angle distribution diagram for both faulty and non-faulty lines as follows: Figure 4 As shown, the negative sequence measured impedance angle of a line with a ground fault is significantly different from that of a non-faulty line. Therefore, the negative sequence measured impedance angle of each line can be used to determine whether the corresponding line has a ground fault. As for the negative sequence measured admittance angle, since the negative sequence measured admittance angle is equal to the negative negative sequence measured impedance angle, there is also a significant difference between the faulty and non-faulty lines. It can be used to determine the faulty line. You can refer to the content of negative sequence measured impedance angle for understanding, which will not be elaborated here.

[0071] Details as follows Figure 1 As shown, the specific steps of the single-circuit fault protection method for the arc suppression coil grounding system in this embodiment are as follows:

[0072] Taking the negative sequence impedance angle as a criterion for judgment as an example, firstly, two reference values ​​are obtained: the negative sequence current setting value of the arc suppression coil grounding system. and the normal negative sequence impedance angle θ set The negative sequence current setting value is calculated according to the following formula:

[0073]

[0074] Where, k k Represents the reliability coefficient. This indicates the negative sequence current generated on the faulty line when a single-phase ground fault occurs on another feeder.

[0075] Normal negative sequence impedance angle θ set This represents the negative sequence impedance angle of each line under normal system operation. The calculation formula can be referenced from the negative sequence measured impedance angle of non-faulty lines. The negative sequence measured impedance angle of non-faulty lines under normal operating conditions is taken as the normal negative sequence impedance angle θ. set .

[0076] When implementing a single-circuit fault protection method for an arc suppression coil grounding system, the system acquires the negative sequence information of each line, i.e., the negative sequence current at the beginning of each line. and negative sequence voltage

[0077] negative sequence current at the beginning Compared with the above negative sequence current setting value Perform numerical comparisons to determine the negative sequence current at the first end. Is it greater than the negative sequence current setting value? If so, it is determined that the corresponding line may have a grounding fault; otherwise, it is determined that the line is operating normally.

[0078] For lines identified as potentially susceptible to grounding faults, further analysis is conducted, specifically by calculating the negative-sequence measured impedance angle θ of the lines at risk of grounding faults. k The negative sequence impedance angle θ will be measured. k With normal negative sequence impedance angle θ set The difference is calculated, and the impedance angle difference is denoted as Δθ.

[0079] Determine whether the impedance angle difference value Δθ belongs to the preset impedance angle difference value range C. θ That is, to determine the negative sequence by measuring the impedance angle θ k With normal negative sequence impedance angle θ set If the difference in the line meets certain numerical conditions, it is determined that the line has a grounding fault; otherwise, it is determined that the line has not a grounding fault.

[0080] More specifically, referring to the phase range of the negative-sequence measured impedance angle for faulty and non-faulty lines mentioned above, the impedance angle difference range C of the negative-sequence measured impedance angle is... θ In the design, to ensure the effectiveness of fault protection and avoid omissions, the impedance angle difference range C is specified. θ The phase difference of the negative sequence measured impedance angle should be greater than the range of the negative sequence measured impedance angle between the faulty and non-faulty lines; therefore, the impedance angle difference range C is taken. θ = [-180°, -90°], which can effectively include the phase difference range of the negative sequence measured impedance angle of faulty and non-faulty lines, thereby playing an effective fault protection role.

[0081] That is, when a negative sequence impedance angle θ is measured on a line that may experience a ground fault. k -180°≤θ k -θ set If the angle is ≤-90°, the line is considered to have a ground fault; otherwise, the line is considered to have no fault.

[0082] Correspondingly, negative order measurement admittance angle The calculation formula is as follows:

[0083]

[0084] Then, the range of admittance angle differences Its principle is similar to that of negative sequence impedance angle θ measurement k The same applies; please refer to the description above for understanding, and it will not be repeated here.

[0085] The following simulation examples will further illustrate the technical effectiveness of the single-circuit fault protection method for the arc suppression coil grounding system described in this embodiment.

[0086] like Figure 5 As shown, a simulation model of a 10kV arc suppression coil grounding system was built using PSCAD. Three lines were set up, with line lengths of 5km, 5km, and 8km respectively, from L1 to L3. The forward sequence parameters of the lines are as follows:

[0087] z1 = (0.105 + j0.08) Ω / km;

[0088] c1 = 0.12 μF / km;

[0089] The zero-sequence parameters of the line are as follows:

[0090] z0 = (1.05 + j5.027) Ω / km;

[0091] c0 = 6.4 × 10 -3 μF / km;

[0092] L p =0.417H.

[0093] Assuming a single-phase open-circuit fault occurs in line L3, the fault state of line L3 is first determined using other methods, such as the zero-sequence current method, as follows:

[0094] Obtain the zero-sequence current at the beginning of each line. and the zero-sequence voltage of the bus Calculate the zero-sequence current for each line. and zero sequence voltage The ratio yields the zero-sequence admittance component Y. i(0) Then, the zero-sequence admittance phase, i.e. the zero-sequence admittance angle, is calculated. If the zero-sequence admittance phase is between (90° and 180°), then the line is determined to be a faulty line. The above method verifies that line L3 is a faulty line.

[0095] By changing the location of the ground fault point in line L3, the negative sequence impedance angle was measured at different fault locations. The results are shown in Table 1 below:

[0096] Table 1. Simulation results for two different fault locations.

[0097]

[0098]

[0099] As shown in Table 1, the negative sequence measured impedance angle of the faulted line remains essentially unchanged, hovering around -92.7°, regardless of the fault location (represented by the distance between the fault point and the busbar). This means the negative sequence measured impedance angle of the faulted line is unaffected by changes in the fault location. This is different from the negative sequence measured impedance angle of a normally operating line, i.e., the normal negative sequence impedance angle θ.set The impedance angle difference Δθ remains around -115.6°, showing a significant difference and falling within the impedance angle difference range C. θ That is, by obtaining the negative sequence measured impedance angle of the line, the faulty line can be accurately identified and then protected, and it is not affected by the location of the fault point.

[0100] By changing the value of the transition resistor in the circuit, the negative sequence impedance angle was measured under different transition resistor values. The results are shown in Table 2 below.

[0101] Table 2. Simulation results for different transition resistances

[0102]

[0103] As shown in Table 2, with the increase of the transition resistor value, the negative sequence measured impedance angle of the faulty line remains basically unchanged, maintaining at around -92.7°. That is, the negative sequence measured impedance angle of the faulty line does not change with the change of the transition resistor value. This is consistent with the negative sequence measured impedance angle of the normally operating line, i.e., the normal negative sequence impedance angle θ. set The impedance angle difference Δθ remains around -115°, showing a significant difference, and falls within the impedance angle difference range C. θ This means that by obtaining the negative sequence impedance angle of the line, the faulty line can be accurately identified and then protected. It is not affected by the value of the transition resistor and can effectively locate the faulty line in lines with different transition resistor values, making it widely applicable.

[0104] This disclosure allows for the calculation of negative sequence measurement impedance or admittance by acquiring the negative sequence current and negative sequence voltage at the beginning of the line, thereby obtaining the negative sequence measurement impedance angle or admittance angle. The faulty line is then identified and protected using the impedance angle or admittance angle. This disclosure can protect against two-point out-of-phase grounding complex faults on a single-circuit line, requiring only the negative sequence information of the line to identify the faulty circuit. It minimizes information acquisition and communication overhead, has low requirements for equipment synchronization, and is easy to apply. Furthermore, the method of this disclosure can still respond and operate even when the two-point grounding positions are constantly changing, unaffected by factors such as the fault location or transition resistance. It is also effective when two points are grounded at the same point, possessing advantages such as strong anti-interference capability, stability, applicability, and high sensitivity.

[0105] This embodiment also provides a single-circuit fault protection system for an arc suppression coil grounding system, including:

[0106] The acquisition module is used to acquire the negative sequence measured impedance angle or negative sequence measured admittance angle of the line in the arc suppression coil grounding system;

[0107] The judgment module is used to determine whether a grounding fault has occurred in the corresponding line based on the obtained negative sequence measured impedance angle or negative sequence measured admittance angle.

[0108] The single-circuit fault protection system of this embodiment is based on the same inventive concept as the single-circuit fault protection method described above, and can be understood with reference to the above description, and will not be repeated here.

[0109] like Figure 6 As shown, this embodiment also provides a computer device, including a processor 101 and a memory 102 connected via a bus signal. The memory 102 stores at least one instruction or at least one program segment. When the at least one instruction or the at least one program segment is loaded by the processor 101, it executes the single-line fault protection method described above. The memory 102 can be used to store software programs and modules. The processor 101 executes various functional applications by running the software programs and modules stored in the memory 102. The memory 102 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for functions, etc.; the data storage area may store data created according to the use of the device, etc. In addition, the memory 102 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 102 may also include a memory controller to provide the processor 101 with access to the memory 102.

[0110] The methods and embodiments provided in this disclosure can be executed in a computer terminal, server, or similar computing device; that is, the aforementioned computer device may include a computer terminal, server, or similar computing device. The internal structure of the computer device may include, but is not limited to, a processor, a network interface, and memory. The processor, network interface, and memory within the computer device may be connected via a bus or other means.

[0111] The processor 101 (or CPU, Central Processing Unit) is the computing and control core of the computer device. The network interface may optionally include a standard wired interface or a wireless interface (such as Wi-Fi, mobile communication interface, etc.). The memory 102 is the storage device in the computer device used to store programs and data. It is understood that the memory 102 here may be a high-speed RAM storage device, or a non-volatile storage device, such as at least one disk storage device; optionally, it may also be at least one storage device located remotely from the processor 101. The memory 102 provides storage space that stores the operating system of the electronic device, which may include, but is not limited to: Windows (an operating system), Linux (an operating system), Android (a mobile operating system), iOS (a mobile operating system), etc., and this disclosure does not limit this; furthermore, the storage space also stores one or more instructions suitable for loading and execution by the processor 101, which may be one or more computer programs (including program code). In the embodiments of this specification, the processor 101 loads and executes one or more instructions stored in the memory 102 to implement the single-circuit fault protection method described in the above method embodiments.

[0112] This disclosure also provides a computer-readable storage medium storing at least one instruction or at least one program segment, which, when loaded by processor 101, executes the single-circuit fault protection method described above. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to this disclosure.

[0113] According to embodiments of this disclosure, the computer-readable storage medium can be a non-volatile computer-readable storage medium. Examples include, but are not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0114] In the description of this disclosure, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this disclosure and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure.

[0115] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims disclosed herein.

Claims

1. A single-circuit fault protection method for an arc suppression coil grounding system, characterized by, According to the negative sequence measurement impedance angle or the negative sequence measurement admittance angle of the line in the arc suppression coil grounding system, whether the corresponding line has a grounding fault is determined; The specific method for determining whether the corresponding line has a grounding fault according to the negative sequence measurement impedance angle or the negative sequence measurement admittance angle of the line in the arc suppression coil grounding system comprises the following steps: Obtaining the negative sequence impedance angle of each line of the arc suppression coil grounding system in a normal operation state, denoted as a normal negative sequence impedance angle ; Obtaining negative sequence measurement impedance angle for a line where a ground fault can occur ; Computing negative sequence measurement impedance angle The difference between the impedance angle of the normal negative sequence impedance angle is recorded as ; determining whether the impedance angle difference value belongs to a preset impedance angle difference interval If yes, it is determined that the line has a ground fault, otherwise it is determined that the line has no ground fault. Alternatively, the negative sequence admittance angle of each line in the normal operation state of the arc suppression coil grounding system is obtained, denoted as a normal negative sequence admittance angle ; Obtaining negative sequence measurement admittance angle for a line where a ground fault can occur ; Calculate the negative-order measurement admittance angle With normal negative order admittance angle The difference in admittance angle is denoted as ; determining whether the admittance angle difference belongs to a preset admittance angle difference interval determining whether the admittance angle difference belongs to a preset admittance angle difference interval if yes, determining that the line has a ground fault, otherwise, determining that the line does not have a ground fault The line that may have a grounding fault is determined through the following steps: Obtaining negative sequence current setting value of arc suppression coil grounding system ; acquiring the negative sequence current of the first end of each line ; determining whether the first end negative sequence current is greater than the negative sequence current setting value if yes, determining that a ground fault possibly occurs on the corresponding line, otherwise determining that the line is in normal operation; The negative sequence measurement impedance angle of the possible ground fault line The calculation is performed in the following steps: Acquiring negative sequence voltage of a line where a ground fault can occur ; The negative sequence measurement impedance angle is calculated according to the following equation : ； The negative sequence measurement admittance angle of the possible ground fault line The calculation is performed in the following steps: Acquiring negative sequence voltage of a line where a ground fault can occur ; The negative sequence measurement admittance angle is calculated according to the following formula : 。 2. The single-circuit fault protection method for the arc suppression coil grounding system according to claim 1, characterized by, The negative sequence current setting value is calculated according to the following formula: ; wherein, denotes the reliability factor, denotes the negative sequence current generated on the faulted line when a single-phase-to-ground fault occurs on another feeder.

3. The single-circuit fault protection method for the arc suppression coil grounding system according to claim 2, characterized in that, The impedance angle difference interval The admittance angle difference interval .

4. A single-circuit reclosing protection system for an arc suppression coil grounding system for implementing the single-circuit reclosing protection method for an arc suppression coil grounding system according to claim 1, characterized by Comprise: An acquisition module is configured to acquire the negative sequence measurement impedance angle or the negative sequence measurement admittance angle of the line in the arc suppression coil grounding system; A determination module is configured to determine whether the corresponding line has a grounding fault according to the obtained negative sequence measurement impedance angle or the negative sequence measurement admittance angle.

5. A computer device comprising a processor and a memory connected by a signal, characterized in that, The memory stores at least one instruction or at least one program, and the at least one instruction or the at least one program is loaded by the processor to execute the single-loop fault protection method of the arc suppression coil grounding system according to any one of claims 1-3.

6. A computer-readable storage medium having stored thereon, at least one instruction or at least one piece of program, characterized in that, The at least one instruction or the at least one program is loaded by the processor to execute the single-loop fault protection method of the arc suppression coil grounding system according to any one of claims 1-3.

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