Method and device for arc extinction of stator ground and rotor ground faults of variable speed pumped storage unit based on machine end injection

Abstract

The application relates to a variable-speed pumped storage unit stator ground fault and rotor ground fault arc extinguishing method and device based on machine end injection. In the case that a variable-speed pumped storage unit ground fault is monitored, the minimum actual voltage corresponding to the phase of the three phases of the variable-speed pumped storage unit is determined as a fault phase, a first electric signal is obtained in the case that the ground fault is a stator ground fault; then, according to the first electric signal, a first arc extinguishing compensation amount is determined, the first arc extinguishing compensation amount is injected from the machine end of the variable-speed pumped storage unit to the stator winding, so that effective arc extinguishing of the stator ground fault is realized; in the case that the ground fault is a rotor ground fault, an injection signal and a second electric signal are obtained, then, according to the injection signal, the fault phase and the second electric signal, a second arc extinguishing compensation amount is determined, the second arc extinguishing compensation amount is injected from the machine end of the variable-speed pumped storage unit to the rotor winding, so that effective arc extinguishing of the rotor ground fault is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fault arc extinction, in particular to a variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinction method and device based on machine terminal injection. BACKGROUND

[0002] Pumped storage is a green, low-carbon, clean and flexible regulating power source with mature technology, economic efficiency and large-scale development conditions. As a large rotating unit, it can play an important role in stabilizing the safe operation of the power grid. The stator single-phase grounding fault and rotor grounding fault of the variable-speed pumped storage unit are the most common and highest probability fault types of large units. At the same time, such grounding faults are often a precursor to winding short circuit faults. With the increase of the capacity of the variable-speed pumped storage unit, the corresponding grounding fault current also increases. If no measures are taken, it will lead to further expansion of the fault and even cause destructive damage to the variable-speed pumped storage unit.

[0003] In the traditional technology, the grounding fault arc extinction of the winding of the variable-speed pumped storage unit is mainly divided into passive arc extinction method and active arc extinction method. The passive arc extinction method cannot compensate for the harmonic components in the fault current; and the active arc extinction method cannot effectively extinguish the rotor winding grounding fault. Therefore, the fault arc extinction method of the traditional technology cannot achieve effective arc extinction. SUMMARY

[0004] Therefore, it is necessary to provide a variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinction method, device, computer equipment, computer readable storage medium and computer program product based on machine terminal injection, which can achieve effective arc extinction, in view of the above technical problems.

[0005] In a first aspect, the present application provides a variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinction method based on machine terminal injection, comprising:

[0006] Monitoring the working state of the variable-speed pumped storage unit;

[0007] When the working state is a grounding fault, obtaining the actual voltage of the three phases of the variable-speed pumped storage unit corresponding to each other;

[0008] Determining that the phase corresponding to the minimum actual voltage is the fault phase;

[0009] When the grounding fault is a stator grounding fault, obtaining a first electric signal of the fault phase;

[0010] According to the first electric signal, determining a first arc extinction compensation amount;

[0011] Injecting the first arc extinction compensation amount from the machine terminal of the variable-speed pumped storage unit to the stator winding of the variable-speed pumped storage unit;

[0012] When the ground fault is a rotor ground fault, an injection signal output by an injection protection device and a second electrical signal of the rotor winding at a working frequency are acquired; wherein the injection protection device is connected with a neutral point of the rotor winding of the variable speed pumped storage unit;

[0013] A second arc suppression compensation quantity is determined according to the injection signal, the fault phase and the second electrical signal;

[0014] The second arc suppression compensation quantity is injected from a machine end of the variable speed pumped storage unit to the rotor winding of the variable speed pumped storage unit.

[0015] In one of the embodiments, the step of determining the first arc suppression compensation quantity according to the first electrical signal comprises:

[0016] A double-frequency fault potential is determined according to the first electrical signal; wherein the first electrical signal comprises a fundamental wave potential of the fault phase of the stator winding, a third harmonic potential of the fault phase, a neutral point fundamental wave voltage and a neutral point third harmonic voltage;

[0017] The first arc suppression compensation quantity is determined according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the double-frequency fault potential.

[0018] In one of the embodiments, the step of determining the first arc suppression compensation quantity according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the double-frequency fault potential comprises:

[0019] The first arc suppression compensation quantity is determined according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the double-frequency fault potential, and based on the following formula; wherein the first arc suppression compensation quantity comprises a fundamental wave arc suppression compensation quantity and a third harmonic arc suppression compensation quantity, and the double-frequency fault potential comprises a fundamental wave fault potential and a third harmonic fault potential:

[0020]

[0021] wherein, U i1 is the fundamental wave arc suppression compensation quantity, U i3 is the third harmonic arc suppression compensation quantity, E f1 is the fundamental wave fault potential, E f3 is the third harmonic fault potential, E A1 is the fundamental wave potential of the fault phase, E A3 is the third harmonic potential of the fault phase.

[0022] In one of the embodiments, the step of determining the double-frequency fault potential according to the first electrical signal comprises:

[0023] A first ground fault position is determined according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, the neutral point fundamental wave voltage and the neutral point third harmonic voltage.

[0024] determine the double-frequency fault potential according to the fundamental potential of the fault phase, the third harmonic potential of the fault phase and the first grounding fault position.

[0025] In one embodiment, the step of determining the second arc extinction compensation amount according to the injection signal, the fault phase and the second electrical signal comprises:

[0026] determining the winding potential according to the injection signal, the fault phase and the second electrical signal; wherein the winding potential is the potential between the port of the variable-speed pumped storage unit and the second grounding fault position;

[0027] determining the second arc extinction compensation amount according to the winding potential.

[0028] In one embodiment, the step of determining the winding potential according to the injection signal, the fault phase and the second electrical signal comprises:

[0029] determining the grounding transition resistance according to the current injection and the voltage injection of the injection signal and the current limiting resistance of the three-phase winding port; wherein the injection signal comprises the current injection and the voltage injection;

[0030] determining the reference potential ratio of each virtual fault point based on the connection sequence of the rotor winding; wherein the reference potential ratio is the potential ratio between the winding potential from the port of the variable-speed pumped storage unit to the virtual fault point and the winding potential from the virtual fault point to the neutral point;

[0031] determining the actual potential ratio after the fault according to the grounding transition resistance, the fault phase, the generator terminal three-phase voltage and the generator terminal current; wherein the second electrical signal comprises the generator terminal three-phase voltage and the generator terminal current;

[0032] determining the virtual fault point corresponding to the minimum absolute difference between the reference potential ratio and each actual potential ratio as the second grounding fault position;

[0033] determining the winding potential according to the second grounding fault position.

[0034] In a second aspect, the application further provides a variable-speed pumped storage unit stator and rotor grounding fault arc extinction device based on generator terminal injection, comprising:

[0035] a monitoring module for monitoring the working state of the variable-speed pumped storage unit;

[0036] an actual voltage acquisition module for acquiring the actual voltage corresponding to each of the three phases of the variable-speed pumped storage unit when the working state is a grounding fault;

[0037] a fault phase determination module for determining the phase corresponding to the minimum actual voltage as the fault phase;

[0038] The first electric signal acquisition module is configured to acquire a first electric signal of the fault phase when the ground fault is a stator ground fault.

[0039] The first arc extinction compensation amount determination module is configured to determine a first arc extinction compensation amount according to the first electric signal.

[0040] The first injection module is configured to inject the first arc extinction compensation amount from a machine end of the variable speed pumped storage unit to a stator winding of the variable speed pumped storage unit.

[0041] The second electric signal acquisition module is configured to acquire an injection signal output by an injection protection device, a fault phase, and a second electric signal of a rotor winding at a working frequency when the ground fault is a rotor ground fault, wherein the injection protection device is connected to a neutral point of the rotor winding of the variable speed pumped storage unit.

[0042] The second arc extinction compensation amount determination module is configured to determine a second arc extinction compensation amount according to the injection signal, the fault phase, and the second electric signal.

[0043] The second injection module is configured to inject the second arc extinction compensation amount from the machine end of the variable speed pumped storage unit to the rotor winding of the variable speed pumped storage unit.

[0044] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any of the above methods for stator ground fault and rotor ground fault arc extinction of a variable speed pumped storage unit based on machine end injection when executing the computer program.

[0045] In a fourth aspect, the present application further provides a computer readable storage medium, which stores a computer program, and the computer program implements the steps of any of the above methods for stator ground fault and rotor ground fault arc extinction of a variable speed pumped storage unit based on machine end injection when executed by a processor.

[0046] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, and the computer program implements the steps of any of the above methods for stator ground fault and rotor ground fault arc extinction of a variable speed pumped storage unit based on machine end injection when executed by a processor.

[0047] The method, device, computer device, computer readable storage medium and computer program product for arc extinguishing of stator ground fault and rotor ground fault of variable-speed pumped storage unit based on machine terminal injection can obtain and determine the phase corresponding to the minimum actual voltage in the three phases of the variable-speed pumped storage unit as the fault phase when monitoring that the variable-speed pumped storage unit has a ground fault, and then further determine the type of the ground fault. In the case of stator ground fault, the first electric signal of the fault phase is obtained. Then, the first arc extinguishing compensation quantity is determined according to the first electric signal, and the first arc extinguishing compensation quantity is injected into the stator winding from the machine terminal of the variable-speed pumped storage unit, so as to realize effective arc extinguishing of the stator ground fault. In the case of rotor ground fault, the injection signal output by the injection protection device connected with the neutral point of the rotor winding of the variable-speed pumped storage unit and the second electric signal of the rotor winding at the working frequency are obtained, and then the second arc extinguishing compensation quantity is determined according to the injection signal, the fault phase and the second electric signal, and the second arc extinguishing compensation quantity is injected into the rotor winding from the machine terminal of the variable-speed pumped storage unit, so as to realize effective arc extinguishing of the rotor ground fault. The method for arc extinguishing of stator ground fault and rotor ground fault of variable-speed pumped storage unit based on machine terminal injection can take into account effective arc extinguishing of stator ground fault and effective arc extinguishing of rotor ground fault, thereby ensuring safe and stable operation of the variable-speed pumped storage unit. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application or the related art. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor based on these drawings.

[0049] Figure 1 An application environment diagram of the method for arc extinguishing of stator ground fault and rotor ground fault of variable-speed pumped storage unit based on machine terminal injection in an embodiment;

[0050] Figure 2 A flowchart of the method for arc extinguishing of stator ground fault and rotor ground fault of variable-speed pumped storage unit based on machine terminal injection in an embodiment;

[0051] Figure 3 An equivalent structure diagram of stator ground fault of variable-speed pumped storage unit in an embodiment;

[0052] Figure 4 A fundamental wave relationship principle diagram of variable-speed pumped storage unit in an embodiment;

[0053] Figure 5 A third harmonic relationship principle diagram of variable-speed pumped storage unit in an embodiment;

[0054] Figure 6 a fundamental voltage phasor diagram of a fault branch when a variable speed pumped storage unit is grounded in an embodiment;

[0055] Figure 7 a third harmonic voltage phasor diagram of a fault branch when a variable speed pumped storage unit is grounded in an embodiment;

[0056] Figure 8 an equivalent structure diagram of a rotor grounding fault of a variable speed pumped storage unit in an embodiment;

[0057] Figure 9 a current simulation result of a grounding fault under simulation in an embodiment;

[0058] Figure 10 a simulation result diagram of a grounding fault current dynamic mode test under simulation in an embodiment;

[0059] Figure 11 a structure block diagram of a stator grounding and rotor grounding fault arc extinguishing device of a variable speed pumped storage unit based on machine end injection in an embodiment;

[0060] Figure 12 an internal structure diagram of a computer device in an embodiment. DETAILED DESCRIPTION

[0061] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0062] It should be noted that the terms "first", "second", and the like used in the present application can be used to describe various elements or signals, but these elements or signals are not limited by these terms. These terms are only used to distinguish the first element or signal from the second element or signal. The terms "include" and "have" and any variations thereof used in the present application are intended to cover non-exclusive inclusion. The term "a plurality of" used in the present application refers to two or more. The term "and / or" used in the present application refers to one of the options, or any combination of a plurality of options.

[0063] The variable speed pumped storage unit stator grounding and rotor grounding fault arc extinguishing method based on machine end injection provided by the embodiments of the present application can be applied to, for example Figure 1The application environment shown. Among them, the data storage system can store the data required by the server 102 to process. The data storage system can be integrated on the server 102, or placed on the cloud or other network servers. The server 102 monitors the working state of the variable speed pumped storage unit in real time, and in the case of monitoring that the working state of the variable speed pumped storage unit is a ground fault, the actual voltage corresponding to each of the three phases of the variable speed pumped storage unit is obtained, and the phase corresponding to the minimum value in the actual voltage is determined as the fault phase. When the ground fault is a stator ground fault, a first electrical signal of the fault phase is obtained; according to the first electrical signal, a first arc extinction compensation amount is determined; the first arc extinction compensation amount is injected from the machine end of the variable speed pumped storage unit to the stator winding of the variable speed pumped storage unit. When the ground fault is a rotor ground fault, an injection signal output by an injection protection device, a fault phase, and a second electrical signal of the rotor winding at the working frequency are obtained; wherein the injection protection device is connected with the neutral point of the rotor winding of the variable speed pumped storage unit; according to the injection signal, the fault phase and the second electrical signal, a second arc extinction compensation amount is determined; the second arc extinction compensation amount is injected from the machine end of the variable speed pumped storage unit to the rotor winding of the variable speed pumped storage unit. The server 102 can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0064] At present, the installed capacity of power storage projects has increased significantly, and the development momentum is rapid. Among the installed capacity distribution of various types of energy storage, the installed capacity proportion of pumped storage is the largest and occupies a dominant position. At present, pumped storage is recognized as the most mature technology, the most optimal economy, and the most large-scale development condition of green, low-carbon, clean and flexible regulation power source. As a large rotating unit, it can play an important role in stabilizing the safe operation of the power grid.

[0065] The ground fault arc extinction of the variable speed pumped storage unit mainly includes passive arc extinction method and active arc extinction method. Among them, the passive method is mainly to ground through the neutral point through the arc suppression coil to compensate for the fault current. However, the arc suppression coil can only basically compensate for single-frequency fault components, cannot compensate for harmonic components in the fault current, and the residual current is still large after compensation. Practical operation experience shows that the existing neutral point grounding methods cannot achieve reliable fault arc extinction under different fault scenarios.

[0066] Active arc extinguishing methods avoid arc reignition in principle by injecting a source to control the fault point voltage below the arc reignition voltage. Wang Yikai et al. in patent CN118399357A "Generator grounding arc extinguishing method, device, electronic equipment and storage medium" inject a current into the neutral point of the generator and combine the measured transition resistance to obtain the generator grounding fault potential. Then, the calculated reverse fault potential is injected into the neutral point of the generator to achieve fault arc extinguishing. Yu Kuo et al. in Proceedings of the CSEE, 2025-03-01, 1-13 "Large generator stator grounding fault voltage reduction arc extinguishing method based on flexible regulation of ground voltage" propose a large generator stator grounding fault voltage reduction arc extinguishing method based on flexible regulation of ground voltage. By connecting a controllable current source in parallel to the ground branch at the neutral point of the generator, the optimal amplitude and phase angle of the injected current are searched, the stator winding fault point voltage is suppressed to zero, the fault arc reignition condition is destroyed, and the grounding fault current is eliminated to achieve stator grounding fault arc extinguishing. These active arc extinguishing methods are based on installing active arc extinguishing devices at the neutral point to inject compensation to achieve arc extinguishing. However, installing active arc extinguishing devices only at the neutral point of the stator winding cannot achieve effective arc extinguishing for rotor winding grounding faults. In addition, since the rotor winding of the variable speed pumped storage unit adopts the special mode of neutral point not grounded, active arc extinguishing devices cannot be installed. In view of this problem, it is urgent to propose a method to achieve effective arc extinguishing for both stator grounding faults and rotor grounding faults of the variable speed pumped storage unit, thereby ensuring the safe and stable operation of the variable speed pumped storage unit.

[0067] In one exemplary embodiment, as shown in Figure 2 a variable speed pumped storage unit stator and rotor grounding fault arc extinguishing method based on machine end injection is provided. The method is applied to the server 102 in Figure 1 for example, which includes:

[0068] S202, monitoring the working state of the variable speed pumped storage unit.

[0069] S204, when the working state is a grounding fault, obtaining three phase actual voltages corresponding to the variable speed pumped storage unit.

[0070] S206, determining the phase corresponding to the minimum actual voltage as the fault phase.

[0071] S208, when the grounding fault is a stator grounding fault, obtaining a first electrical signal of the fault phase.

[0072] In the case of a stator grounding fault, the fault phase can be accurately determined by the minimum value in the actual voltage of each phase, thereby ensuring the reliability of the first electrical signal.

[0073] S210, determining a first arc-extinguishing compensation amount according to the first electric signal.

[0074] S212, injecting the first arc-extinguishing compensation amount from a machine end of the variable-speed pumped storage unit to a stator winding of the variable-speed pumped storage unit.

[0075] The injection of the first arc-extinguishing compensation amount can be completed through an active arc-extinguishing device. Specifically, the active arc-extinguishing device is connected to a stator machine end of the variable-speed pumped storage unit, so that the first arc-extinguishing compensation amount is injected to the stator winding of the variable-speed pumped storage unit through the stator machine end of the variable-speed pumped storage unit, thereby realizing effective arc extinguishing of the stator single-phase ground fault.

[0076] S214, when the ground fault is a rotor ground fault, obtaining an injection signal output by an injection protection device and a second electric signal of the rotor winding at a working frequency; wherein the injection protection device is connected to a neutral point of the rotor winding of the variable-speed pumped storage unit.

[0077] The injection signal output by the injection protection device includes an injection current and an injection voltage; the frequency of the injection current and the frequency of the injection voltage are both set to a frequency that does not affect the normal operation of the variable-speed pumped storage unit. In theory, the frequency of the injection current and the injection voltage can be lower than the working frequency (50 Hz), and in actual application, the frequency of the injection current and the injection voltage can both be 20 Hz.

[0078] S216, determining a second arc-extinguishing compensation amount according to the injection signal, the fault phase and the second electric signal.

[0079] S218, injecting the second arc-extinguishing compensation amount from the machine end of the variable-speed pumped storage unit to the rotor winding of the variable-speed pumped storage unit.

[0080] Correspondingly, the injection of the second arc-extinguishing compensation amount can also be completed through an active arc-extinguishing device. Specifically, the active arc-extinguishing device is connected to a rotor machine end of the variable-speed pumped storage unit, so that the second arc-extinguishing compensation amount is injected to the rotor winding of the variable-speed pumped storage unit through the rotor machine end of the variable-speed pumped storage unit, thereby realizing effective arc extinguishing of the rotor ground fault.

[0081] In the method for arc extinguishing of stator ground fault and rotor ground fault of variable speed pumped storage unit based on machine terminal injection, in the case that the variable speed pumped storage unit is monitored to have a ground fault, the phase corresponding to the minimum actual voltage among the three phases of the variable speed pumped storage unit is determined as the fault phase, and then the type of the ground fault is further judged. In the case that the ground fault is a stator ground fault, a first electric signal of the fault phase is obtained. Then, according to the first electric signal, a first arc extinguishing compensation quantity is determined, and the first arc extinguishing compensation quantity is injected from the machine terminal of the variable speed pumped storage unit to the stator winding, so as to realize effective arc extinguishing of the stator ground fault. In the case that the ground fault is a rotor ground fault, an injection signal output by an injection protection device connected with a neutral point of the rotor winding of the variable speed pumped storage unit and a second electric signal of the rotor winding at the working frequency are obtained, and then according to the injection signal, the fault phase and the second electric signal, a second arc extinguishing compensation quantity is determined, and the second arc extinguishing compensation quantity is injected from the machine terminal of the variable speed pumped storage unit to the rotor winding, so as to realize effective arc extinguishing of the rotor ground fault. The method for arc extinguishing of stator ground fault and rotor ground fault of variable speed pumped storage unit based on machine terminal injection can take into account effective arc extinguishing of the stator ground fault and effective arc extinguishing of the rotor ground fault, so as to guarantee safe and stable operation of the variable speed pumped storage unit.

[0082] In an exemplary embodiment, the step of determining the first arc extinguishing compensation quantity according to the first electric signal comprises:

[0083] determining a double-frequency fault potential according to the first electric signal; wherein the first electric signal comprises a fundamental wave potential of the fault phase of the stator winding, a third harmonic wave potential of the fault phase, a neutral point fundamental wave voltage and a neutral point third harmonic wave voltage.

[0084] determining the first arc extinguishing compensation quantity according to the fundamental wave potential of the fault phase, the third harmonic wave potential of the fault phase and the double-frequency fault potential.

[0085] In the case of arc extinguishing compensation for the stator ground fault, both the fundamental wave component and the harmonic component in the fault current need to be compensated, so as to realize effective arc extinguishing. Therefore, in the case of determining the double-frequency fault potential, both the fundamental wave parameters (the fundamental wave potential of the fault phase and the neutral point fundamental wave voltage) and the harmonic wave parameters (the third harmonic wave potential of the fault phase and the neutral point third harmonic wave voltage) are considered, so as to ensure that the first arc extinguishing compensation quantity finally determined includes the fundamental wave component and the harmonic component.

[0086] In an exemplary embodiment, the step of determining the first arc extinguishing compensation quantity according to the fundamental wave potential of the fault phase, the third harmonic wave potential of the fault phase and the double-frequency fault potential comprises:

[0087] Based on the fundamental potential of the fault phase, the third harmonic potential of the fault phase, and the dual-frequency fault potential, and using the following formula, the first arc suppression compensation amount is determined; wherein, the first arc suppression compensation amount includes the fundamental arc suppression compensation amount and the third harmonic arc suppression compensation amount, and the dual-frequency fault potential includes the fundamental fault potential and the third harmonic fault potential:

[0088]

[0089] Among them, U i1 U is the fundamental wave arc suppression compensation amount. i3 E is the third harmonic arc suppression compensation amount. f1 For the fundamental fault potential, E f3 The third harmonic fault potential is given by E, where X is the fault phase. X1 E is the fundamental potential of the fault phase. X3 The third harmonic potential of the faulty phase.

[0090] like Figure 3 As shown, taking phase A as the fault phase as an example, the formula for determining the fundamental wave arc suppression compensation in the first arc suppression compensation is:

[0091] ,

[0092] Among them, E A1 The fundamental potential of phase A is given.

[0093] like Figure 4 As shown, A represents phase A, B represents phase B, C represents phase C, N is the neutral point of the stator winding of the variable speed pumped storage unit, T is the stator terminal of the variable speed pumped storage unit, and E... A1 E is the fundamental potential of phase A of the variable speed pumped storage unit. B1 E is the fundamental potential of phase B of the variable speed pumped storage unit. C1 For the fundamental potential of phase C of a variable speed pumped storage unit, U A1 U represents the voltage at camera A's terminal before active control is performed after a ground fault. B1 U represents the voltage at camera B before active control is performed after a ground fault. C1 U' is the voltage at the C-side of the camera after a ground fault and before active control is performed. A1 U' is the voltage at camera A after active control following a ground fault. B1 U' is the voltage at camera B after active regulation following a ground fault. C1 U represents the voltage at the C-camera terminal after active regulation following a ground fault. T1 Characterized as the fundamental terminal voltage of the stator winding after a ground fault but before active regulation, U' T1Characterized by the fundamental terminal voltage of the stator winding after an active control following a ground fault, U n1 Characterized as the fundamental neutral voltage U' after a ground fault occurs and before active regulation is performed. n1 Characterized as the fundamental neutral voltage after active regulation following a ground fault, U AB U is the voltage between phase A and phase B. BC U is the voltage between phase B and phase C. CAB This is the voltage between phase C and phase A.

[0094] Depend on Figure 4 It can be seen that after voltage regulation at the stator winding terminals, the fault point voltage is suppressed to 0, thus achieving arc suppression of the fundamental component in the stator fault.

[0095] like Figure 5 As shown, taking phase A as the fault phase as an example, the formula for determining the third harmonic arc suppression compensation in the first arc suppression compensation is:

[0096] ,

[0097] Among them, E A3 The third harmonic potential of phase A is given.

[0098] Figure 5 Middle,U T3 Characterized as the fundamental neutral voltage U' after a ground fault occurs and before active regulation is performed. T3 Characterized as the fundamental neutral voltage after active regulation following a ground fault, U n3 To characterize the neutral point third harmonic voltage after a ground fault and before active regulation, U' n3 This characterizes the neutral point third harmonic voltage after active regulation following a ground fault. Figure 5 It can be seen that after voltage regulation at the stator winding terminals, the fault point voltage is suppressed to 0, thus achieving arc suppression of harmonic components in stator faults.

[0099] In one exemplary embodiment, determining the dual-frequency fault potential based on the first electrical signal includes:

[0100] The location of the first ground fault is determined based on the fundamental potential of the fault phase, the third harmonic potential of the fault phase, the fundamental voltage of the neutral point, and the third harmonic voltage of the neutral point.

[0101] The dual-frequency fault potential is determined based on the fundamental potential of the fault phase, the third harmonic potential of the fault phase, and the location of the first ground fault.

[0102] Specifically, taking the A-phase fault as an example, the fundamental potential of the fault phase, the third harmonic potential of the fault phase, the neutral point fundamental voltage and the neutral point third harmonic voltage are brought into the following formula, and the fault position value is in the range of 0~1, so that the unique solution of the minimum value of the formula is obtained, that is, the first grounding fault position:

[0103]

[0104] wherein, α represents the fault position; L n represents the inductance value of the arc suppression coil connected to the neutral point of the variable speed pumped storage unit; C t is the equivalent ground capacitance value of each phase at the machine end of the direct connection system of the variable speed pumped storage unit, C a is the equivalent ground capacitance value of the fault phase coil of the variable speed pumped storage unit, C ∑ is the sum of the stator winding and the three-phase ground capacitance of the external direct connection system; E Ai3 is the midpoint of the i-th turn of the fault phase coil to the neutral point third harmonic potential, n is the total number of turns of the stator winding in one phase of the variable speed pumped storage unit; ω is the angular velocity, and w=2πf, wherein f is the power frequency (50Hz); j is an imaginary number, j 2 =-1.

[0105] The specific derivation process of the above formula is as follows: when the variable speed pumped storage unit occurs grounding fault, the sum of the grounding fault current flowing through the fault point, the system ground capacitance current and the neutral point arc suppression coil current is 0, which satisfies:

[0106] ,

[0107] ,

[0108] wherein, R g is the transition resistance.

[0109] By combining the two formulas, the transition resistance R g can be eliminated, and the following formula is obtained:

[0110]

[0111] Therefore, the fundamental fault potential E f1 and the third harmonic fault potential E f3 can be represented by the fault position α:

[0112]

[0113] The relationship diagrams are shown in Figure 6 and Figure 7 , wherein, Figure 6 is the geometric relationship between the fundamental fault potential and the fundamental phase potential under 60° phase distribution, wherein, θA1 denotes the angle between E f1 and E A1 . Figure 7 is the geometric relationship between the third harmonic fault potential and the third harmonic phase potential under the 180° phase relationship, wherein θ A3 denotes the angle between E f3 and E A3 . The formula of the fundamental fault potential E f1 and the third harmonic fault potential E f3 is substituted into the obtained relationship formula eliminating the transition resistance, so that the formula for determining the first grounding fault position is obtained.

[0114] Based on the first grounding fault position, the formula of the fundamental fault potential E f1 and the third harmonic fault potential E f3 is substituted into the formula, so that the double-frequency fault potential is inversely deduced.

[0115] Correspondingly, in the case of other phase faults except the A phase, the parameters of the A phase in the above formula are replaced by the parameters of the other phase, so that the double-frequency fault potential under the other phase fault is determined by the same idea, which will not be described here.

[0116] In an exemplary embodiment, the step of determining the second arc extinction compensation amount according to the injection signal, the fault phase and the second electric signal comprises:

[0117] determining a winding potential according to the injection signal, the fault phase and the second electric signal; wherein the winding potential is the potential between the port of the variable speed pumped storage unit and the second grounding fault position.

[0118] determining the second arc extinction compensation amount according to the winding potential.

[0119] The winding potential is brought into the following formula, so that the second arc extinction compensation amount is determined:

[0120] ,

[0121] wherein U in is the second arc extinction compensation amount, and E R is the winding potential.

[0122] In an exemplary embodiment, the step of determining the winding potential according to the injection signal, the fault phase and the second electric signal comprises:

[0123] determining a grounding transition resistance according to the current limiting resistance of the three-phase winding port, the injection current and the injection voltage; wherein the injection signal comprises the injection current and the injection voltage.

[0124] Determine the reference potential ratio of each virtual fault point based on the connection sequence of the rotor winding; wherein the reference potential ratio is the potential ratio between the winding potential from the port of the variable speed pumped storage unit to the virtual fault point and the winding potential from the virtual fault point to the neutral point.

[0125] Determine the actual potential ratio after the fault according to the ground transition resistance, the fault phase, the terminal three-phase voltage and the terminal current; wherein the second electric signal comprises the terminal three-phase voltage and the terminal current.

[0126] Determine the virtual fault point corresponding to the minimum absolute difference between the reference potential ratio and each actual potential ratio as the second ground fault position.

[0127] Determine the winding potential according to the second ground fault position.

[0128] Specifically, as shown in the figure, take the A phase as the fault phase as an example for description: the current injection, the voltage injection and the current limiting resistance of the three-phase winding port are substituted into the following formula, and the ground transition resistance can be determined: Figure 8

[0129]

[0130] Wherein, R f is the ground transition resistance; E1 is the voltage injection; I1 is the current injection; R Z is the current limiting resistance of the three-phase winding port; Re( ) represents the real part.

[0131] For any branch of the rotor winding, the following settings can be made: the connection sequence of the slot conductor from the neutral point to the port is recorded as (x1U, x2L) → (x3U, x4L) → … → (x 2i-1 U, x 2i L), and the slot conductor induced potential amplitude is recorded as E c ∠β xk , wherein β xk =±x k θ, θ is the slot pitch electrical angle.

[0132] Therefore, the value corresponding to the connection sequence of the rotor winding of the variable speed pumped storage unit can be substituted into the following formula, and the reference potential ratio of each virtual fault point can be obtained:

[0133]

[0134] Wherein, d is the reference potential ratio when the ground fault occurs at the connection of the slot conductors x k and x k+1 .

[0135] ​​​The ground transition resistance, the fault phase, the machine terminal three-phase voltage and the machine terminal current are brought into the following formula to obtain the actual potential ratio after the fault:

[0136] ,

[0137] wherein, U A is the A-phase port-to-ground voltage, U B is the B-phase port-to-ground voltage, U C is the C-phase port-to-ground voltage, U A , U B and U C are the machine terminal three-phase voltages; I2 is the working frequency phasor of the machine terminal current, which can be separated by Fourier transform.

[0138] Thus, the absolute difference between the actual potential ratio d' and each reference potential ratio can be determined, and the virtual fault point corresponding to the minimum absolute difference between the reference potential ratio and each actual potential ratio is taken as the second ground fault position, so that the ground fault positioning is realized.

[0139] The second ground fault position is substituted into the following formula to determine the winding potential:

[0140] ,

[0141] It should be noted that in the case of other phase faults, the port-to-ground voltage of the fault phase is substituted into U X in the formula, and then the above idea is installed to determine the winding potential:

[0142] ,

[0143] The specific solving idea when the other phase is the fault phase can refer to the idea of solving the second arc extinction compensation amount when the A phase is the fault phase, which will not be repeated here.

[0144] In one embodiment, to verify the reliability of the stator ground and rotor ground fault arc extinction method based on machine terminal injection of the variable speed pumped storage unit, simulation experiment verification and dynamic model test verification are performed on the stator ground and rotor ground fault arc extinction method based on machine terminal injection of the variable speed pumped storage unit, specifically:

[0145] In the simulation experiment verification, simulation experiments are performed based on a simulation platform such as PSCAD (Power Systems Computer Aided Design, electromagnetic transient simulation software) / EMTDC (Electromagnetic Transients including DC) software, and a quasi-distributed parameter model is established to carry out simulation analysis. Among them, the capacity of the variable speed pumped storage unit is set to 30 kVA, and the rated voltage is 10.5 kV.

[0146] As Figure 9 shown, the variable speed pumped storage unit is set to occur ground fault at 0.2s, and the ground transition resistance is 500Ω. The fault positions are respectively at 0.29375 of the stator A phase winding, 0.5 of the rotor A phase winding, 0.79375 of the stator B phase winding and the rotor C phase machine end. At 0.24s, the first arc extinguishing compensation quantity determined according to the variable speed pumped storage unit stator ground and rotor ground fault arc extinguishing method based on machine end injection is injected into the stator winding of the variable speed pumped storage unit from the machine end of the variable speed pumped storage unit through the active arc extinguishing device, and the second arc extinguishing compensation quantity determined according to the variable speed pumped storage unit stator ground and rotor ground fault arc extinguishing method based on machine end injection is injected into the rotor winding of the variable speed pumped storage unit from the machine end of the variable speed pumped storage unit through the active arc extinguishing device.

[0147] From Figure 9 it can be seen that under different fault conditions, after injecting the arc extinguishing compensation quantity determined according to the variable speed pumped storage unit stator ground and rotor ground fault arc extinguishing method based on machine end injection, the fault current is suppressed to 0, realizing effective arc extinguishing.

[0148] In the dynamic simulation test verification, the stator dynamic simulation test model of the variable speed pumped storage unit and the rotor dynamic simulation test model of the variable speed pumped storage unit are established in the dynamic simulation test room, and the variable speed pumped storage unit stator ground and rotor ground fault arc extinguishing method based on machine end injection is analyzed by dynamic simulation test under different load conditions of the variable speed pumped storage unit. Among them, the dynamic simulation unit capacity of the variable speed pumped storage unit is set to 15kVA, the rated voltage is 400V, the neutral point is grounded by arc suppression coil, and the over compensation degree is 5%. At the same time, the programmable AC power supply is used to simulate the active arc extinguishing device, and the capacity is 15kVA, which can output the fundamental wave and third harmonic voltage with any effective value and phase. The sliding resistance is used to simulate the ground transition resistance, and the adjustable range is 0~2000Ω.

[0149] The tap position of the stator A phase winding 6.5% and the rotor A phase winding 20% is selected for separate dynamic simulation test verification. The programmable AC power supply is set to output voltage equal to the calculated output value, and during the test, the switch between the fault position and the sliding resistor is used to set the ground fault, and the switch between the programmable AC power supply and the neutral point of the dynamic simulation unit is used to input the active arc extinguishing device.

[0150] Single-phase ground faults with transition resistances of 50Ω and 500Ω are set under no-load and full-load conditions of the variable speed pumped storage unit, and the variable speed pumped storage unit is set to occur ground fault at 0.2s, for example, and the fault current waveform is as shown in Figure 10 . Figure 10The simulation diagram verified by the dynamic model test under the condition of 6.5% tap position of the stator A phase winding and 50Ω transition resistance, the simulation diagram verified by the dynamic model test under the condition of 20% tap position of the stator A phase winding and 50Ω transition resistance, the simulation diagram verified by the dynamic model test under the condition of 6.5% tap position of the stator A phase winding and 500Ω transition resistance, and the simulation diagram verified by the dynamic model test under the condition of 20% tap position of the stator A phase winding and 500Ω transition resistance are respectively carried out under the conditions of no-load and full load.

[0151] It can be seen that, after the active arc extinguishing device is put in, the fault current is suppressed to 0 under different load conditions (including no-load and full load), effectively verifying that the arc extinguishing effect of the stator grounding and rotor grounding fault arc extinguishing method based on machine terminal injection of the variable-speed pumped storage unit is not affected by the operating conditions of the variable-speed pumped storage unit, and has strong engineering practicability.

[0152] It should be understood that, although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps. It can be understood that the steps in different embodiments can be freely combined as needed, and various non-contradictory schemes formed by the combination are within the scope of protection of the present application.

[0153] Based on the same inventive concept, the embodiments of the present application also provide a variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinguishing device based on machine terminal injection for implementing the variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinguishing method based on machine terminal injection involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, and therefore the specific limitations in one or more variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinguishing device embodiments provided below can refer to the limitations of the variable-speed pumped storage unit stator grounding and rotor grounding fault arc extinguishing method described above, and will not be repeated here.

[0154] In one exemplary embodiment, as Figure 11As shown, a variable speed pumped storage unit stator ground and rotor ground fault arc extinction device 300 based on machine end injection is provided, comprising: a monitoring module 302, an actual voltage acquisition module 304, a fault phase determination module 306, a first electric signal acquisition module 308, a first arc extinction compensation amount determination module 310, a first injection module 312, a second electric signal acquisition module 314, a second arc extinction compensation amount determination module 316, and a second injection module 318, wherein:

[0155] The monitoring module 302 is configured to monitor the working state of the variable speed pumped storage unit.

[0156] The actual voltage acquisition module 304 is configured to acquire the actual voltage of each phase of the variable speed pumped storage unit when the working state is a ground fault.

[0157] The fault phase determination module 306 is configured to determine the phase corresponding to the minimum actual voltage as the fault phase.

[0158] The first electric signal acquisition module 308 is configured to acquire the first electric signal of the fault phase when the ground fault is a stator ground fault.

[0159] The first arc extinction compensation amount determination module 310 is configured to determine the first arc extinction compensation amount based on the first electric signal.

[0160] The first injection module 312 is configured to inject the first arc extinction compensation amount from the machine end of the variable speed pumped storage unit to the stator winding of the variable speed pumped storage unit.

[0161] The second electric signal acquisition module 314 is configured to acquire the injection signal output by the injection type protection device, the fault phase, and the second electric signal of the rotor winding at the working frequency when the ground fault is a rotor ground fault; wherein the injection type protection device is connected to the neutral point of the rotor winding of the variable speed pumped storage unit.

[0162] The second arc extinction compensation amount determination module 316 is configured to determine the second arc extinction compensation amount based on the injection signal, the fault phase, and the second electric signal.

[0163] The second injection module 318 is configured to inject the second arc extinction compensation amount from the machine end of the variable speed pumped storage unit to the rotor winding of the variable speed pumped storage unit.

[0164] In an exemplary embodiment, the first arc extinction compensation amount determination module 310 comprises a dual-frequency fault potential determination module and a first arc extinction compensation amount determination submodule.

[0165] The double-frequency fault potential determination module is configured to determine a double-frequency fault potential according to the first electrical signal; wherein the first electrical signal comprises a fundamental wave potential of the fault phase of the stator winding, a third harmonic potential of the fault phase, a neutral point fundamental wave voltage, and a neutral point third harmonic voltage.

[0166] The first arc extinction compensation quantity determination submodule is configured to determine a first arc extinction compensation quantity according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, and the double-frequency fault potential.

[0167] In an exemplary embodiment, the first arc extinction compensation quantity determination submodule comprises a first calculation module.

[0168] The first calculation module is configured to determine the first arc extinction compensation quantity according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, and the double-frequency fault potential, and based on the following formula; wherein the first arc extinction compensation quantity comprises a fundamental wave arc extinction compensation quantity and a third harmonic arc extinction compensation quantity, and the double-frequency fault potential comprises a fundamental wave fault potential and a third harmonic fault potential:

[0169]

[0170] wherein U i1 is the fundamental wave arc extinction compensation quantity, U i3 is the third harmonic arc extinction compensation quantity, E f1 is the fundamental wave fault potential, E f3 is the third harmonic fault potential, E A1 is the fundamental wave potential of the fault phase, E A3 is the third harmonic potential of the fault phase.

[0171] In an exemplary embodiment, the double-frequency fault potential determination module comprises a first ground fault location determination module and a double-frequency fault potential determination submodule.

[0172] The first ground fault location determination module is configured to determine a first ground fault location according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, the neutral point fundamental wave voltage, and the neutral point third harmonic voltage.

[0173] The double-frequency fault potential determination submodule is configured to determine a double-frequency fault potential according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, and the first ground fault location.

[0174] In an exemplary embodiment, the second arc extinction compensation quantity determination module 316 comprises a winding potential determination module and a second arc extinction compensation quantity determination submodule.

[0175] The winding potential determination module is configured to determine a winding potential according to the injection signal, the fault phase, and the second electrical signal; wherein the winding potential is a potential between a port of the variable-speed pumped storage unit and a second ground fault location.

[0176] The second arc extinction compensation quantity determination submodule is configured to determine the second arc extinction compensation quantity according to the winding potential.

[0177] In an exemplary embodiment, the winding potential determination module comprises a ground transition resistance determination module, a reference potential ratio determination module, an actual potential ratio determination module, a second ground fault location determination module, and a winding potential determination submodule.

[0178] The ground transition resistance determination module is configured to determine the ground transition resistance according to the current limiting resistance of the three-phase winding port, the injected current, and the injected voltage; wherein the injected signal comprises the injected current and the injected voltage.

[0179] The reference potential ratio determination module is configured to determine the reference potential ratio of each virtual fault point based on the connection sequence of the rotor winding; wherein the reference potential ratio is the potential ratio between the winding potential from the port of the variable speed pumped storage unit to the virtual fault point and the winding potential from the virtual fault point to the neutral point.

[0180] The actual potential ratio determination module is configured to determine the actual potential ratio after the fault according to the ground transition resistance, the fault phase, the generator terminal three-phase voltage, and the generator terminal current; wherein the second electric signal comprises the generator terminal three-phase voltage and the generator terminal current.

[0181] The second ground fault location determination module is configured to determine that the virtual fault point corresponding to the minimum absolute difference between the reference potential ratio and each actual potential ratio is the second ground fault location.

[0182] The winding potential determination submodule determines the winding potential according to the second ground fault location.

[0183] Each module in the above variable speed pumped storage unit stator ground and rotor ground fault arc extinction device based on the generator terminal injection can be realized by software, hardware, and combinations thereof, in whole or in part. Each module can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to each module.

[0184] In an exemplary embodiment, a computer device is provided, which can be a server, and the internal structure diagram thereof can be as shown in Figure 12As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through the system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capability. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the first electrical signal, the injection signal and the second electrical signal. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with the terminal outside through the network connection. The computer program is executed by the processor to realize a machine-side injection-based variable-speed pumped storage unit stator ground and rotor ground fault arc extinction method.

[0185] Those skilled in the art can understand that, Figure 12 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0186] In one exemplary embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of any method of the above-mentioned machine-side injection-based variable-speed pumped storage unit stator ground and rotor ground fault arc extinction method.

[0187] In one embodiment, a computer readable storage medium is provided, having a computer program stored thereon, and the computer program is executed by the processor to implement the steps of any method of the above-mentioned machine-side injection-based variable-speed pumped storage unit stator ground and rotor ground fault arc extinction method.

[0188] In one embodiment, a computer program product is provided, including a computer program, and the computer program is executed by the processor to implement the steps of any method of the above-mentioned machine-side injection-based variable-speed pumped storage unit stator ground and rotor ground fault arc extinction method.

[0189] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0190] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0191] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for arc extinction of stator ground and rotor ground faults of a variable speed pumped storage unit based on machine end injection, characterized in that, The method comprises: monitoring the working state of the variable speed pumped storage unit; when the working state is a ground fault, obtaining actual voltages of three phases of the variable speed pumped storage unit one by one; determining that the phase corresponding to the minimum actual voltage is a fault phase; when the ground fault is a stator ground fault, obtaining a first electrical signal of the fault phase; determining a first arc extinction compensation amount according to the first electrical signal; injecting the first arc extinction compensation amount from the machine end of the variable speed pumped storage unit to the stator winding of the variable speed pumped storage unit; when the ground fault is a rotor ground fault, obtaining an injection signal output by an injection protection device and a second electrical signal of the rotor winding at the working frequency; wherein the injection protection device is connected to the neutral point of the rotor winding of the variable speed pumped storage unit; determining a second arc extinction compensation amount according to the injection signal, the fault phase and the second electrical signal; injecting the second arc extinction compensation amount from the machine end of the variable speed pumped storage unit to the rotor winding of the variable speed pumped storage unit.

2. The method of claim 1, wherein, The method comprises: determining a double-frequency fault potential according to the first electrical signal; wherein the first electrical signal comprises a fundamental wave potential of the fault phase of the stator winding, a third harmonic potential of the fault phase, a neutral point fundamental wave voltage and a neutral point third harmonic voltage; determining a first arc extinction compensation amount according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the double-frequency fault potential.

3. The method of claim 2, wherein, The method comprises: determining a first arc extinction compensation amount according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the double-frequency fault potential based on the following formula; wherein the first arc extinction compensation amount comprises a fundamental wave arc extinction compensation amount and a third harmonic arc extinction compensation amount, and the double-frequency fault potential comprises a fundamental wave fault potential and a third harmonic fault potential: wherein U i1 is the fundamental arc suppression compensation, U i3 is the third harmonic arc suppression compensation, E f1 is the fundamental fault potential, E f3 is the third harmonic fault potential, E A1 is the fundamental potential of the fault phase, E A3 is the third harmonic potential of the fault phase.

4. The method of claim 2, wherein, The method comprises: determining a first ground fault position according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase, the neutral point fundamental wave voltage and the neutral point third harmonic voltage; determining the double-frequency fault potential according to the fundamental wave potential of the fault phase, the third harmonic potential of the fault phase and the first ground fault position.

5. The method of claim 1, wherein, The method comprises: determining a winding potential according to the injection signal, the fault phase and the second electrical signal; wherein the winding potential is a potential between the port of the variable speed pumped storage unit and a second ground fault position; determining a second arc extinction compensation amount according to the winding potential.

6. The method of claim 5, wherein, The method comprises: Determine the ground transition resistance according to the current injection resistance, the injected current and the injected voltage of the three-phase winding port; wherein the injection signal comprises the injected current and the injected voltage; Determine the reference potential ratio of each virtual fault point based on the connection sequence of the rotor winding; wherein the reference potential ratio is the potential ratio between the winding potential from the port of the variable-speed pumped storage unit to the virtual fault point and the winding potential from the virtual fault point to the neutral point; Determine the actual potential ratio after the fault according to the ground transition resistance, the fault phase, the generator terminal three-phase voltage and the generator terminal current; wherein the second electric signal comprises the generator terminal three-phase voltage and the generator terminal current; Determine the virtual fault point corresponding to the minimum absolute difference between the reference potential ratio and each actual potential ratio as the second ground fault position; Determine the winding potential according to the second ground fault position.

7. A machine end injection based variable speed pumped storage generator stator ground and rotor ground fault arc extinction device, characterized in that, The device comprises: A monitoring module for monitoring the working state of a variable-speed pumped storage unit; An actual voltage acquisition module for acquiring the actual voltage corresponding to each of the three phases of the variable-speed pumped storage unit when the working state is a ground fault; A fault phase determination module for determining the phase corresponding to the minimum actual voltage as the fault phase; A first electric signal acquisition module for acquiring the first electric signal of the fault phase when the ground fault is a stator ground fault; A first arc extinction compensation amount determination module for determining the first arc extinction compensation amount according to the first electric signal; A first injection module for injecting the first arc extinction compensation amount from the generator terminal of the variable-speed pumped storage unit to the stator winding of the variable-speed pumped storage unit; A second electric signal acquisition module for acquiring the injection signal output by the injection type protection device, the fault phase and the second electric signal of the rotor winding at the working frequency when the ground fault is a rotor ground fault; wherein the injection type protection device is connected with the neutral point of the rotor winding of the variable-speed pumped storage unit; A second arc extinction compensation amount determination module for determining the second arc extinction compensation amount according to the injection signal, the fault phase and the second electric signal; A second injection module for injecting the second arc extinction compensation amount from the generator terminal of the variable-speed pumped storage unit to the rotor winding of the variable-speed pumped storage unit.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor executes the computer program to realize the steps of the method in any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method in any one of claims 1 to 6.

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