Short-circuit fault protection method and system for variable-speed pumped storage unit with selectivity

Abstract

The invention discloses a short-circuit fault protection method and system for a variable-speed pumped storage unit with selectivity, and the method comprises the steps: carrying out the transformation of three-phase current coordinates of a stator side winding and a rotor side winding of the variable-speed pumped storage unit through Clark transformation, and obtaining a different-frequency current differential function; respectively constructing a starting criterion and a braking criterion of short-circuit protection according to the harmonic characteristic component of the different-frequency current differential function; obtaining a stator and rotor protection action value and a starting value according to the starting criterion and the braking criterion; and performing fault distinguishing and selective protection on a stator short-circuit fault and a rotor short-circuit fault of the variable-speed pumped storage unit according to the comparison between the operating values and the starting value and the comparison between the operating values. The rotor short-circuit fault can be accurately and effectively recognized, misoperation during stator short-circuit fault is avoided, and rapid and reliable protection is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of relay protection of variable speed pumped storage units, and in particular relates to a selective short-circuit fault protection method and system for variable speed pumped storage units. Background Art

[0002] Rotor short circuit fault is one of the common fault types of variable speed pumped storage units. In existing technical means, the protection method for rotor short circuit fault mostly relies on the overcurrent protection integrated in the AC excitation system. However, this method has poor sensitivity when reflecting rotor winding short circuit fault and cannot meet the standard of safe operation of the unit.

[0003] In addition, the existing frequency-differential protection method provides a possible way to solve the rotor short-circuit fault, but it has extremely serious drawbacks. When the stator short-circuits, it often malfunctions. When the stator short-circuits, the differential protection will mistakenly judge it as a rotor winding fault, which will then trigger unnecessary protection actions. This makes it very likely that the unit will experience unplanned shutdown, which will undoubtedly interfere with the stability of the power system and seriously hinder the normal operation of the unit.

[0004] Under the background that large-capacity variable-speed pumped storage units have extremely stringent requirements on the rapidity, real-time performance and high reliability of protection, the problems caused by the defects of the existing technology have become more prominent and urgent. In view of the problems existing in the existing methods, a selective short-circuit fault protection method for variable-speed pumped storage units is proposed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a selective short-circuit fault protection method and system for a variable-speed pumped storage unit to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a selective short-circuit fault protection method for a variable-speed pumped storage unit, comprising:

[0007] Through Clark transformation, the three-phase current coordinates of the stator and rotor windings of the variable speed pumped storage unit are transformed to obtain the differential current function with different frequencies.

[0008] According to the harmonic characteristic components of the different-frequency current differential function, a starting criterion and a braking criterion of short-circuit protection are respectively constructed;

[0009] According to the starting criterion and the braking criterion, a stator and rotor protection action value and a starting value are obtained;

[0010] According to the comparison between the action value and the starting value, and the comparison between the action values, the variable speed pumped storage unit is subjected to fault differentiation and selective protection for stator short circuit fault and rotor short circuit fault.

[0011] Preferably, the harmonic characteristic components of the heterodyne current differential function include: a first component after a rotor winding short-circuit fault and a second component after a stator winding short-circuit fault; wherein, the first component includes: a 2sf component and a 4sf component; and the second component includes: 2f, 2(1-s)f, and 2sf components.

[0012] Preferably, for a rotor winding short-circuit fault, a first starting criterion for rotor winding short-circuit protection is constructed according to the fault characteristics of the first component, and the formula is:

[0013]

[0014] Among them, I op.r is the rotor protection action value, I set To protect the starting value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t);

[0015] The first braking criterion of rotor winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component:

[0016]

[0017] Among them, K rel is the reliability coefficient, K rel I op.s is the stator protection action value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t), respectively.

[0018] Preferably, the fault differentiation and selective protection of the variable speed pumped storage unit for stator short circuit fault and rotor short circuit fault includes:

[0019] If the rotor protection action value is greater than the protection start value and less than the stator protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected;

[0020] If the rotor protection action values ​​are both greater than the protection starting value and the stator protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected.

[0021] Preferably, for a stator winding short-circuit fault, a second starting criterion for stator winding short-circuit protection is constructed according to the fault characteristics of the second component, and the formula is:

[0022]

[0023] Among them, K rel is the reliability coefficient, K rel I op.s is the stator protection action value, I set To protect the starting value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t);

[0024] The second braking criterion for stator winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component:

[0025]

[0026] Among them, I op.r is the rotor protection action value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t), respectively.

[0027] Preferably, the fault differentiation and selective protection of the variable speed pumped storage unit for stator short circuit fault and rotor short circuit fault includes:

[0028] If the stator protection action value is greater than the protection start value and less than the rotor protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected;

[0029] If the stator protection action values ​​are both greater than the protection starting value and the rotor protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected.

[0030] In a second aspect, the present invention discloses a selective short-circuit fault protection system for a variable-speed pumped storage unit, comprising:

[0031] The coordinate transformation module is used to transform the three-phase current coordinates of the stator and rotor side windings of the variable speed pumped storage unit through Clark transformation to obtain the heterogeneous current differential function;

[0032] A criterion construction module, used to construct a starting criterion and a braking criterion of short-circuit protection according to the harmonic characteristic components of the hetero-frequency current differential function;

[0033] A value acquisition module, used to obtain a stator and rotor protection action value and a starting value according to the starting criterion and the braking criterion;

[0034] The fault protection module is used to distinguish and selectively protect the variable speed pumped storage unit from stator short circuit faults and rotor short circuit faults based on the comparison between the action value and the starting value, and the comparison between the action values.

[0035] In a third aspect, the present invention further discloses a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method described in the first aspect when executed by a processor.

[0036] In a fourth aspect, the present invention further discloses a computer program product, comprising a computer program, which implements the steps of the method described in the first aspect when executed by a processor.

[0037] Compared with the prior art, the present invention has the following advantages and technical effects:

[0038] The present invention provides a selective short-circuit fault protection method for a variable-speed pumped storage unit, comprising: firstly, transforming the three-phase current coordinates of the stator and rotor side windings of the variable-speed pumped storage unit through Clark transformation to obtain a hetero-frequency current differential function; secondly, constructing a starting criterion and a braking criterion for short-circuit protection respectively according to the harmonic characteristic components of the hetero-frequency current differential function; then, obtaining a stator-rotor protection action value and a starting value according to the starting criterion and the braking criterion; finally, performing fault differentiation and selective protection of the variable-speed pumped storage unit between stator short-circuit faults and rotor short-circuit faults according to a comparison between the action value and the starting value, and a comparison between the protection action values.

[0039] The present invention can accurately and effectively identify rotor short-circuit faults, avoid false operation in case of stator short-circuit faults, and can sensitively operate under rotor winding inter-turn and inter-phase short-circuit faults, with an operating time of less than 40ms, which is 91.6% less than the operating time of the converter overcurrent protection in inter-phase short-circuit faults, thus realizing fast and reliable protection. At the same time, it can provide selective protection for stator winding short circuits, and serve as backup protection for traditional transverse differential current protection and longitudinal differential current protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0041] Figure 1 is a flow chart of a method according to an embodiment of the present invention;

[0042] Figure 2 The rotor turn-to-turn short circuit fault of the embodiment of the present invention, the stator and rotor three-phase current waveforms before and after the fault, f(i αs,i βs ) and h 2 f(i αr ,i βr ) and the calculated differential value d(t) variation diagram;

[0043] Figure 3 This is a diagram showing the protection action of a rotor turn-to-turn short-circuit fault according to an embodiment of the present invention;

[0044] Figure 4 The stator turn-to-turn short circuit fault of the embodiment of the present invention, the stator and rotor three-phase current waveforms before and after the fault, f(i αs ,i βs ) and h 2 f(i αr ,i βr ) and the calculated differential value d(t) variation diagram;

[0045] Figure 5 This is a diagram showing the protection action of a stator turn-to-turn short-circuit fault according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0048] First, the technical terms involved in the following embodiments are explained.

[0049] Clark transform, also known as α-β transform, is a mathematical tool used to convert three-phase electrical signals into two-phase electrical signals. In the field of electrical engineering, Clark transform is mainly used to analyze and control three-phase AC power systems. Its basic principle is to convert the time domain components of the three-phase system (in the abc coordinate system) into two components in the orthogonal stationary coordinate system (αβ).

[0050] Working principle: Clark transformation realizes the conversion of three-phase coordinate system (abc) to two-phase orthogonal coordinate system (αβ) through basis transformation. In a three-phase system, the current or voltage signals are Ia, Ib, and Ic respectively, and these three signals differ by 120° on phases A, B, and C. Clark transformation overlaps the α axis with the a axis, and extends vector a along the direction of the origin O to make an auxiliary line, with ∠boe and ∠coe equal to 60°. By calculating the projection length of vectors b and c to the α axis and β axis, the basis transformation matrix can be obtained, thereby realizing the coordinate transformation.

[0051] Application scenarios: Clark transform is widely used in inverters, brushless DC motor control or frequency converter control. By using the two signals α and β in the control algorithm, the controller can achieve more accurate output and response. For example, when performing PI control or other closed-loop control, Clark transform can simplify the analysis and calculation process and improve the stability and response speed of the system.

[0052] Embodiment 1

[0053] like Figure 1 As shown, this embodiment provides a selective short-circuit fault protection method for a variable-speed pumped storage unit, comprising:

[0054] S1. Through Clark transformation, the three-phase current coordinates of the stator and rotor side windings of the variable speed pumped storage unit are transformed to obtain the differential current function of different frequencies;

[0055] Specifically, Clark transformation converts the three-phase abc coordinate system to the two-phase stationary αβ coordinate system, and the stator side current i of the variable speed pumped storage unit in the αβ coordinate system can be obtained: αs and i βs :

[0056]

[0057] Among them, I s is the amplitude of the three-phase current on the stator side during normal operation, ω s is the angular frequency of the stator side current;

[0058] The instantaneous value of the αβ current is calculated to obtain f(i αs ,i βs ) is always equal to the square of the stator side phase current amplitude, and the formula is:

[0059]

[0060] Furthermore, similarly, f(i αr ,i βr ) is always equal to the square of the rotor side phase current amplitude, and the formula is:

[0061]

[0062] Similar to the amplitude ratio relationship of the transformer, the stator and rotor voltage and current of the variable speed pumped storage unit also have a ratio relationship, specifically:

[0063]

[0064] Among them, E s and E r are the induced potential amplitudes on the stator and rotor sides respectively; N s and N r are the turns of each phase single-branch winding on the stator and rotor sides respectively; k ws and k wr are the fundamental wave winding coefficients of the stator and rotor sides respectively.

[0065] According to the measured data, the transformation ratio N r k wr / N s k ws The actual measured data is the data measured by the current transformer when the unit is operating normally, and the corrected current ratio is recorded as h. This embodiment innovatively obtains the frequency-differential current function of the variable-speed pumped storage unit:

[0066] d(t)=h 2 f(i αr ,i βr )-f(i αs ,i βs )

[0067] S2. constructing a starting criterion and a braking criterion for short-circuit protection respectively according to the harmonic characteristic components of the heterofrequency current differential function;

[0068] Furthermore, the harmonic characteristic components of the heterodyne current differential function include: a first component after a rotor winding short-circuit fault and a second component after a stator winding short-circuit fault; wherein the first component includes: a 2sf component and a 4sf component; and the second component includes: 2f, 2(1-s)f, and 2sf components.

[0069] Specifically, after the rotor winding short circuit fault, the differential value d(t) is no longer 0, and has significant 2sf and 4sf components. The 2sf component is a common fault feature of stator and rotor winding short circuit faults.

[0070] As an innovative implementation method, for the rotor winding short-circuit fault, the first starting criterion of the rotor winding short-circuit protection is constructed based on the fault characteristics of the 2sf component and the 4sf component, and the formula is:

[0071]

[0072] Among them, I op.r is the rotor protection action value, I set To protect the starting value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t);

[0073] As an innovative implementation method, the first braking criterion of the rotor winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component:

[0074]

[0075] Among them, K rel is the reliability coefficient, K rel I op.s is the stator protection action value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t), respectively.

[0076] S3. Obtaining a stator and rotor protection action value and a starting value according to the starting criterion and the braking criterion;

[0077] S4. Based on the comparison between the action value and the starting value, and the comparison between the protection action values, the variable speed pumped storage unit is subjected to fault differentiation and selective protection between stator short circuit fault and rotor short circuit fault.

[0078] Furthermore, for the rotor winding short-circuit fault, the fault differentiation and selective protection of the variable speed pumped storage unit between the stator short-circuit fault and the rotor short-circuit fault include:

[0079] If the rotor protection action value is greater than the protection start value and less than the stator protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected;

[0080] If the rotor protection action values ​​are both greater than the protection starting value and the stator protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected.

[0081] Specifically, when the rotor protection action value I op.r Greater than protection start value I set , but less than the stator protection action value K rel I op.s When , it is judged that a stator winding short circuit fault has occurred, and the rotor winding short circuit protection will not malfunction. At the same time, it is greater than the protection starting value I set And stator protection action value K rel I op.sOnly when the fault occurs is it determined that the rotor winding is short-circuited, and the rotor winding short-circuit protection operates correctly.

[0082] In this embodiment, if the characteristic harmonic amount of stator short circuit is used as the action value and the characteristic harmonic amount of rotor short circuit is used as the braking value, selective stator winding short circuit protection can also be implemented, which serves as backup protection for traditional stator winding protection, such as transverse differential current protection and longitudinal differential current protection.

[0083] As an innovative implementation method, for a stator winding short-circuit fault, a second starting criterion for stator winding short-circuit protection is constructed according to the fault characteristics of the second component, and the formula is:

[0084]

[0085] Among them, K rel I op.s is the stator protection action value, I set To protect the starting value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t);

[0086] As an innovative implementation method, the second braking criterion for stator winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component:

[0087]

[0088] Among them, I op.r is the rotor protection action value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t), respectively.

[0089] Furthermore, the fault differentiation and selective protection of the variable speed pumped storage unit for stator short circuit fault and rotor short circuit fault include:

[0090] If the stator protection action value is greater than the protection start value and less than the rotor protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected;

[0091] If the stator protection action values ​​are both greater than the protection starting value and the rotor protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected.

[0092] Specifically, when the stator protection action value K rel I op.s Greater than protection start value I set , but less than the rotor protection action value I op.r, it is determined that a rotor winding short circuit fault has occurred, and the stator winding short circuit protection will not malfunction. At the same time, it is greater than the protection starting value I set And rotor protection action value I op.r Only when the stator winding is short-circuited is it determined that there is a stator winding short-circuit fault, and the stator winding short-circuit protection operates correctly.

[0093] Simulation verification:

[0094] This embodiment takes a certain actual variable-speed pumped storage unit as an example. The number of pole pairs of the generator motor is 3, and its synchronous speed is 1000r / min. The rotor winding has one branch per phase, and each branch consists of 15 turns of coils connected in series. Multiple winding taps are drawn out from the side of the generator motor to set the internal faults of the unit. The fault transition resistance of the short-circuit fault experiment is 3.2Ω, and the fault transition resistance of each ground fault experiment is 1.6Ω. During the experiment, the rotor speed was about 950r / min, and the corresponding rotor side operating frequency was about 2.5Hz, and the period was about 400ms. In the experimental analysis results, the time when the fault occurred was the 0th second, which is the time when the sudden change of the recording element started. The effective value of the rated current on the stator side of the experimental unit is 18.23A, so the starting value I can be obtained. set =(0.15×18.23) 2 =7.4775. In addition, the reliability coefficient is K rel is 1.5.

[0095] Set the rotor turn-to-turn short-circuit fault, the fault turn difference is 5 turns, the stator and rotor three-phase current waveforms before and after the fault, f(i αs ,i βs ) and h 2 f(i αr ,i βr ) and the calculated differential value d(t) changes, such as Figure 2 As shown. Figure 3 It can be seen that the rotor protection action value I op.r The set value (protection start value) is reached at 34.1ms. set , proving that the protection method has good speed.

[0096] Set the stator inter-turn short circuit fault, and the fault turn difference is 4 turns. After the fault, the stator and rotor three-phase current waveforms and the differential value d(t) waveforms are as follows: Figure 4 Protection action conditions, such as Figure 5 As shown, after the fault occurs, the rotor protection action value I can be observed op.r Successfully reached the starting setting value I setThe threshold reaches 12.5ms. The reason for this phenomenon is that when the stator winding encounters a short circuit fault, a very significant 2sf component will be generated. The proposed protection method uses the comprehensive effective value of the 2f component and the 2(1-s)f component to construct the braking criterion. The stator protection action value K rel I op.s The time to reach the set value is earlier than the rotor protection action value, which is only 9.8ms. Moreover, at any time point after 9.8ms, the stator protection action value is always greater than the rotor protection action value, and the stator winding short-circuit protection acts quickly and accurately.

[0097] In summary, it has been effectively verified that the proposed rotor short-circuit fault protection method can accurately avoid the occurrence of false operation when facing a stator winding short-circuit fault, showing excellent selectivity and providing reliable guarantee for the stable operation of the variable-speed pumped storage unit.

[0098] Embodiment 2

[0099] Based on the same inventive concept, this embodiment discloses a selective short-circuit fault protection system for a variable-speed pumped storage unit, comprising:

[0100] The coordinate transformation module is used to transform the three-phase current coordinates of the stator and rotor side windings of the variable speed pumped storage unit through Clark transformation to obtain the heterogeneous current differential function;

[0101] A criterion construction module, used to construct a starting criterion and a braking criterion of short-circuit protection according to the harmonic characteristic components of the hetero-frequency current differential function;

[0102] A value acquisition module, used to obtain stator and rotor action values ​​and starting values ​​according to the starting criterion and the braking criterion;

[0103] The fault protection module is used to distinguish and selectively protect the variable speed pumped storage unit from stator short circuit faults and rotor short circuit faults based on the comparison between the action value and the starting value, and the comparison between the action values.

[0104] The selective variable speed pumped storage unit short-circuit fault protection system provided in this embodiment has all the advantages of the selective variable speed pumped storage unit short-circuit fault protection system provided in the first embodiment.

[0105] Embodiment 3

[0106] This embodiment further discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first embodiment are implemented.

[0107] Embodiment 4

[0108] This embodiment also discloses a computer program product, including a computer program, which implements the steps of the method described in the first embodiment when executed by a processor.

[0109] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A selective short-circuit fault protection method for variable-speed pumped storage units, characterized in that: The following steps are involved: Through Clark transformation, the three-phase current coordinates of the stator and rotor windings of the variable speed pumped storage unit are transformed to obtain the differential current function with different frequencies. According to the harmonic characteristic components of the different-frequency current differential function, a starting criterion and a braking criterion of short-circuit protection are respectively constructed; According to the starting criterion and the braking criterion, a stator and rotor protection action value and a starting value are obtained; According to the comparison between the action value and the starting value, and the comparison between the action values, the variable speed pumped storage unit is subjected to fault differentiation and selective protection for stator short circuit fault and rotor short circuit fault.

2. The method according to claim 1, characterized in that The harmonic characteristic components of the heterodyne current differential function include: a first component after a rotor winding short-circuit fault and a second component after a stator winding short-circuit fault; wherein the first component includes: a 2sf component and a 4sf component; and the second component includes: 2f, 2(1-s)f, and 2sf components.

3. The method according to claim 2, characterized in that For the rotor winding short-circuit fault, according to the fault characteristics of the first component, the first starting criterion of the rotor winding short-circuit protection is constructed, and the formula is: Among them, I op.r is the rotor protection action value, I set To protect the starting value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t); The first braking criterion of rotor winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component: Among them, K rel is the reliability coefficient, K rel I op.s is the stator protection action value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t), respectively.

4. The method according to claim 3, characterized in that The fault differentiation and selective protection of stator short circuit fault and rotor short circuit fault of variable speed pumped storage unit include: If the rotor protection action value is greater than the protection start value and less than the stator protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected; If the rotor protection action values ​​are both greater than the protection starting value and the stator protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected.

5. The method according to claim 2, characterized in that: For the stator winding short-circuit fault, according to the fault characteristics of the second component, the second starting criterion of the stator winding short-circuit protection is constructed, and the formula is: Among them, K rel is the reliability coefficient, K rel I op.s is the stator protection action value, I set To protect the starting value, d 2f (t), d 2(1-s)f (t) are the effective values ​​of the 2f component and the 2(1-s)f component in the differential value d(t); The second braking criterion for stator winding short-circuit protection is constructed with the effective values ​​corresponding to the 2f component and the 2(1-s)f component: Among them, I op.r is the rotor protection action value, d 2sf (t), d 4sf (t) are the effective values ​​of the 2sf component and the 4sf component in the differential value d(t), respectively.

6. The method according to claim 5, characterized in that The fault differentiation and selective protection of stator short circuit fault and rotor short circuit fault of variable speed pumped storage unit include: If the stator protection action value is greater than the protection start value and less than the rotor protection action value, it is a rotor winding short circuit fault, and the rotor winding is selectively protected; If the stator protection action values ​​are both greater than the protection starting value and the rotor protection action value, it is a stator winding short circuit fault, and the stator winding is selectively protected.

7. A selective variable speed pumped storage unit short circuit fault protection system, characterized in that: include: The coordinate transformation module is used to transform the three-phase current coordinates of the stator and rotor side windings of the variable speed pumped storage unit through Clark transformation to obtain the heterogeneous current differential function; A criterion construction module, used to construct a starting criterion and a braking criterion of short-circuit protection according to the harmonic characteristic components of the hetero-frequency current differential function; A value acquisition module, used to obtain a stator and rotor protection action value and a starting value according to the starting criterion and the braking criterion; The fault protection module is used to distinguish and selectively protect the variable speed pumped storage unit from stator short circuit faults and rotor short circuit faults based on the comparison between the action value and the starting value, and the comparison between the action values.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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