Method and system for preventing influence of voltage loop abnormity on positive-sequence low-voltage protection

Abstract

The invention discloses a method and system for preventing influence of voltage loop abnormity on positive-sequence low-voltage protection, and relates to the technical field of power system relay protection, and the method comprises the steps: obtaining three-phase voltage collection data and three-phase current collection data of protected equipment under positive-sequence low-voltage protection, and determining a three-phase voltage effective value and a three-phase current effective value; based on the three-phase voltage effective value and the three-phase current effective value, whether a target starting condition of positive-sequence low-voltage protection is met or not is judged; the target starting conditions comprise a positive sequence voltage effective value judgment condition, a positive sequence low voltage once voltage judgment condition and a positive sequence low voltage protection locking judgment condition; and if the duration of the positive-sequence low-voltage protection meeting the target starting condition exceeds the preset action time of the positive-sequence low-voltage protection, controlling the action of the positive-sequence low-voltage protection. The technical problem that in the prior art, when the voltage loop is abnormal, the positive-sequence low-voltage function protection action behavior has an incorrect hidden danger is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection of power systems, and in particular to a method and a system for preventing an abnormal voltage circuit from influencing positive sequence low voltage protection. Background Art

[0002] The positive sequence low voltage protection function can be used as a backup protection for the generators of embedded power plants and as a backup protection for important motors. In the power grid, voltage drops may be due to various reasons, such as grid load fluctuations, equipment failures, short circuits, etc., which may damage the equipment or affect its normal operation. The positive sequence low voltage protection system can monitor the voltage of the power grid. When the voltage drops to a certain level, it will initiate protection measures, such as disconnecting the circuit or reducing the load, to avoid damage to the equipment or unstable operation. This protection measure can help maintain the stability of the power system and the safe operation of the equipment, and also help avoid potential accidents. Therefore, positive sequence low voltage protection is widely used in relay protection.

[0003] At present, the blocking function of positive sequence low voltage protection is usually realized by an input node. When the input node becomes 1, the positive sequence low voltage protection function is blocked, otherwise the positive sequence low voltage protection function is opened. The input node is mainly connected to the output node of other devices. When the output node is abnormal or the input node itself is abnormal, the voltage circuit is abnormal, and there is a hidden danger that the positive sequence low voltage function protection action behavior is incorrect, which reduces the reliability of the positive sequence low voltage protection. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for preventing voltage loop abnormalities from affecting positive sequence low voltage protection in order to solve at least one of the above technical problems.

[0005] In the first aspect, an embodiment of the present invention provides a method for preventing voltage circuit abnormalities from affecting positive-sequence low voltage protection, which is applied to positive-sequence low voltage protection of an electric power system; comprising: obtaining three-phase voltage acquisition data and three-phase current acquisition data of a protected device of the positive-sequence low voltage protection; determining the three-phase voltage effective value and the three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data; judging whether the target starting conditions of the positive-sequence low voltage protection are met based on the three-phase voltage effective value and the three-phase current effective value; the target starting conditions include a positive-sequence voltage effective value judgment condition, a positive-sequence low voltage previous voltage judgment condition and a positive-sequence low voltage protection lockout judgment condition; if the duration for which the positive-sequence low voltage protection meets the target starting conditions exceeds the preset action time of the positive-sequence low voltage protection, the positive-sequence low voltage protection action is controlled.

[0006] Furthermore, the three-phase voltage effective values ​​include: positive sequence voltage effective value, negative sequence voltage effective value, zero sequence voltage effective value, maximum phase-to-phase voltage effective value, minimum phase-to-phase voltage effective value; the three-phase current effective values ​​include: maximum phase current effective value and negative sequence current effective value.

[0007] Furthermore, the positive-sequence voltage effective value determination condition includes: judging whether the positive-sequence voltage effective value is less than a preset positive-sequence low voltage function threshold; if so, the positive-sequence voltage effective value determination condition is satisfied.

[0008] Furthermore, the conditions for judging whether the positive-sequence low voltage had been under pressure include: a first judgment condition, a second judgment condition, a third judgment condition and a return condition; wherein, the first judgment condition includes: the effective value of the positive-sequence voltage is continuously greater than a preset positive-sequence low voltage function threshold; the second judgment condition includes: the protection function of the positive-sequence low voltage protection has not been activated; the third judgment condition includes: the protection function of the positive-sequence low voltage protection is activated; if the first judgment condition, the second judgment condition and the third judgment condition are simultaneously satisfied for more than a first preset time, then the return condition returns to the condition that the positive-sequence low voltage had been under pressure.

[0009] Furthermore, the return condition includes: after the protection function of the positive-sequence low voltage protection is activated, the positive-sequence low voltage once existed judgment condition returns after a second preset time; after the protection function of the positive-sequence low voltage protection is exited, the positive-sequence low voltage once existed judgment condition returns immediately.

[0010] Furthermore, the positive-sequence low voltage protection lockout judgment condition includes: if the lockout judgment criterion of the positive-sequence low voltage protection is not met, the positive-sequence low voltage protection lockout judgment condition is met; wherein, the lockout judgment criterion includes: the lockout condition judgment logic of the three-phase voltage circuit abnormality, the lockout condition judgment logic of the single-phase voltage circuit abnormality, the lockout condition judgment logic of the two-phase voltage circuit abnormality and the negative-sequence voltage lockout condition judgment logic; when any one of the lockout condition judgment logic of the three-phase voltage circuit abnormality, the lockout condition judgment logic of the single-phase voltage circuit abnormality, the lockout condition judgment logic of the two-phase voltage circuit abnormality and the negative-sequence voltage lockout condition judgment logic is met, the lockout judgment criterion is met, otherwise, the lockout judgment criterion is not met.

[0011] Furthermore, the locking condition judgment logic of the three-phase voltage circuit abnormality includes: the maximum phase current effective value is less than the first preset ratio of the rated current, and the maximum phase-to-phase voltage effective value is less than the second preset ratio of the rated voltage value; the locking condition judgment logic of the single-phase voltage circuit abnormality includes: the zero-sequence voltage effective value is greater than the second preset ratio of the rated voltage value, and the difference between the maximum phase-to-phase voltage effective value and the minimum phase-to-phase voltage effective value is greater than the third preset ratio of the rated voltage value; the locking condition judgment logic of the two-phase voltage circuit abnormality includes: the minimum phase-to-phase voltage effective value is less than the third preset ratio of the rated voltage value, and the zero-sequence voltage effective value is greater than the second preset ratio of the rated voltage value; the negative-sequence voltage locking condition judgment logic includes: the negative-sequence current effective value is less than the second preset ratio of the rated current, and the negative-sequence voltage effective value is greater than the fourth preset ratio of the rated voltage value.

[0012] In the second aspect, an embodiment of the present invention further provides a system for preventing voltage circuit abnormalities from affecting positive-sequence low voltage protection, which is applied to positive-sequence low voltage protection of power systems; it comprises: an acquisition module, a determination module, a judgment module and an action module; wherein the acquisition module is used to acquire three-phase voltage acquisition data and three-phase current acquisition data of the protected equipment of the positive-sequence low voltage protection; the determination module is used to determine the three-phase voltage effective value and the three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data; the judgment module is used to judge whether the target start-up conditions of the positive-sequence low voltage protection are met based on the three-phase voltage effective value and the three-phase current effective value; the target start-up conditions include positive-sequence voltage effective value judgment conditions, positive-sequence low voltage once had voltage judgment conditions and positive-sequence low voltage protection lockout judgment conditions; the action module is used to control the positive-sequence low voltage protection action if the duration for which the positive-sequence low voltage protection meets the target start-up conditions exceeds the preset action time of the positive-sequence low voltage protection.

[0013] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method provided in the embodiment of the present invention when executing the computer program.

[0014] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method provided in the embodiment of the present invention is implemented.

[0015] The present invention provides a method and system for preventing the influence of voltage circuit abnormality on positive-sequence low voltage protection. When the positive-sequence low voltage meets the set action constant, the positive-sequence low voltage protection opening condition is judged in combination with the line voltage, negative-sequence voltage, phase current and negative-sequence current conditions. This can solve the problem of incorrect action behavior of the positive-sequence low voltage protection function caused by voltage circuit abnormality, improve the reliability of the positive-sequence low voltage protection function in the relay protection device, and alleviate the technical problem in the prior art that the positive-sequence low voltage protection action behavior has the hidden danger of incorrect action behavior when the voltage circuit is abnormal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A flow chart of a method for preventing voltage loop abnormality from affecting positive sequence low voltage protection provided by an embodiment of the present invention;

[0018] Figure 2 A logic diagram of a target start-up condition of a positive sequence low voltage protection provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of a system for preventing voltage circuit abnormality from affecting positive-sequence low voltage protection provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1

[0022] Figure 1 1 is a flow chart of a method for preventing voltage loop abnormality from affecting positive sequence low voltage protection according to an embodiment of the present invention, and the method is applied to positive sequence low voltage protection of power systems. Figure 1 As shown, the method specifically comprises the following steps:

[0023] Step S102, acquiring three-phase voltage data and three-phase current data of a protected device for positive sequence low voltage protection. Optionally, the protected device includes a generator or a motor of a power system.

[0024] Step S104, determining the three-phase voltage effective value and the three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data.

[0025] Step S106, based on the three-phase voltage effective value and the three-phase current effective value, determine whether the target start-up conditions of the positive-sequence low voltage protection are met; the target start-up conditions include the positive-sequence voltage effective value judgment condition, the positive-sequence low voltage previous voltage judgment condition and the positive-sequence low voltage protection lockout judgment condition.

[0026] Step S108: If the duration during which the positive-sequence low-voltage protection meets the target start-up condition exceeds the preset action time of the positive-sequence low-voltage protection, the positive-sequence low-voltage protection is controlled to act.

[0027] In the embodiment of the present invention, the three-phase voltage data and the three-phase current data of the protected equipment are first collected at a preset frequency, and the collected data are converted to obtain the three-phase voltage effective value and the three-phase current effective value. Among them, the three-phase voltage effective value includes: the positive sequence voltage effective value, the negative sequence voltage effective value, the zero sequence voltage effective value, the maximum phase-to-phase voltage effective value, and the minimum phase-to-phase voltage effective value; the three-phase current effective value includes: the maximum phase current effective value and the negative sequence current effective value.

[0028] In an optional implementation provided by an embodiment of the present invention, the positive sequence low voltage protection collects the three-phase voltage sampling points of the protected device at a constant frequency. Three-phase current sampling points in They are phase A, phase B and phase C respectively. All are set according to this definition.

[0029] Then, the sampling point is converted into a vector value Fs=R+iI through the full-cycle Fourier algorithm, and the calculation formula is as follows:

[0030] real part of a vector value

[0031] real part of a vector value

[0032] In the above formula, N represents the number of sampling points of an elbow, and f [j] is an array of sampling points.

[0033] Through the vector value calculation formula and three-phase voltage sampling points Calculate the three-phase voltage vector value

[0034] Through the vector value calculation formula and three-phase current sampling points Calculate the three-phase voltage vector value

[0035] Calculate the positive sequence voltage vector value U by using the positive sequence calculation formula 1 , and its calculation formula is as follows:

[0036]

[0037] Calculate the positive sequence voltage vector value U by using the negative sequence calculation formula 2 , and its calculation formula is as follows:

[0038]

[0039] Calculate the negative sequence current vector value I by using the negative sequence calculation formula 2 , and its calculation formula is as follows:

[0040]

[0041] Calculate the zero-sequence voltage vector value 3U by the zero-sequence calculation formula 0 , and its calculation formula is as follows:

[0042]

[0043] The phase-to-phase voltage is calculated using the phase-to-phase voltage formula, which is as follows:

[0044]

[0045] Calculate the three phase-to-phase voltage vector values ​​using the above formula and

[0046] The effective value calculation formula of the vector value is as follows:

[0047]

[0048] Convert the vector values ​​obtained above into corresponding effective values: positive sequence voltage effective value U 1 , negative sequence voltage effective value U 2 , three phase voltage effective values ​​U ab , U bc , U ca , negative sequence current effective value I 2 , three phase current effective values ​​I a ,I b ,I c ;

[0049] Compare the three phase-to-phase voltage effective values ​​to obtain the corresponding maximum phase-to-phase voltage effective value UPP_Max and the minimum phase-to-phase voltage RMS value U PP_Min ;

[0050] Compare the three-phase current effective values ​​and obtain the corresponding maximum phase current effective value I _Max .

[0051] In the embodiment of the present invention, the target start-up conditions of the positive sequence low voltage protection include the following three conditions:

[0052] Condition 1: The positive sequence voltage effective value judgment condition;

[0053] Condition 2: The positive sequence low voltage has had a voltage discrimination condition;

[0054] Condition 3: positive sequence low voltage protection lockout judgment condition;

[0055] When all three conditions above are met, the starting conditions of the positive-sequence low-voltage protection function are met. When the time when the starting conditions of the positive-sequence low-voltage protection function are met exceeds the positive-sequence low-voltage protection action time, the positive-sequence low-voltage protection is activated and the relay protection device trips.

[0056] Figure 2 FIG. 1 is a logic diagram of a target start condition of a positive sequence low voltage protection provided according to an embodiment of the present invention. Figure 2 As shown:

[0057] Specifically, the positive sequence voltage effective value judgment conditions include:

[0058] Determine whether the positive sequence voltage effective value is less than the preset positive sequence low voltage function threshold;

[0059] If yes, the positive sequence voltage effective value judgment condition is met.

[0060] Specifically, the positive sequence low voltage has been under pressure judgment conditions include: the first judgment condition, the second judgment condition, the third judgment condition and the return condition; among which,

[0061] The first judgment condition includes: the positive sequence voltage effective value is continuously greater than the preset positive sequence low voltage function threshold;

[0062] The second judgment condition includes: the protection function of the positive sequence low voltage protection does not operate;

[0063] The third judgment condition includes: the protection function of the positive sequence low voltage protection is put into operation;

[0064] If the first discrimination condition, the second discrimination condition and the third discrimination condition are satisfied simultaneously for more than the first preset time, then under the return condition, the positive sequence low voltage once existed discrimination condition is satisfied.

[0065] Preferably, the first preset time is 0.1 second.

[0066] Specifically, the return conditions include:

[0067] After the protection function of the positive sequence low voltage protection is activated, the positive sequence low voltage has been under pressure judgment condition returns after the second preset time;

[0068] After the protection function of the positive-sequence low voltage protection is exited, the positive-sequence low voltage once existed judgment condition is immediately returned.

[0069] Preferably, the second preset time is 0.2 seconds.

[0070] Specifically, the positive sequence low voltage protection lockout judgment condition includes: if the lockout judgment criterion of the positive sequence low voltage protection is not satisfied, then the positive sequence low voltage protection lockout judgment condition is satisfied; wherein,

[0071] The blocking criteria include: blocking condition judgment logic for abnormal three-phase voltage circuit, blocking condition judgment logic for abnormal single-phase voltage circuit, blocking condition judgment logic for abnormal two-phase voltage circuit and negative sequence voltage blocking condition judgment logic;

[0072] When any one of the three-phase voltage circuit abnormality locking condition judgment logic, the single-phase voltage circuit abnormality locking condition judgment logic, the two-phase voltage circuit abnormality locking condition judgment logic and the negative-sequence voltage locking condition judgment logic is met, the locking criterion is met and the positive-sequence low voltage protection function is locked; otherwise, the locking criterion is not met.

[0073] Among them, the lockout condition judgment logic of the abnormal three-phase voltage circuit includes: the maximum phase current effective value is less than a first preset ratio of the rated current, and the maximum phase-to-phase voltage effective value is less than a second preset ratio of the rated voltage value;

[0074] The lockout condition judgment logic for abnormal single-phase voltage circuit includes: the effective value of the zero-sequence voltage is greater than a second preset ratio of the rated voltage value, and the difference between the maximum phase-to-phase voltage effective value and the minimum phase-to-phase voltage effective value is greater than a third preset ratio of the rated voltage value;

[0075] The lockout condition judgment logic for abnormal two-phase voltage circuit includes: the minimum phase-to-phase voltage effective value is less than a third preset ratio of the rated voltage value, and the zero-sequence voltage effective value is greater than a second preset ratio of the rated voltage value;

[0076] The negative sequence voltage locking condition judgment logic includes: the negative sequence current effective value is less than a second preset ratio of the rated current, and the negative sequence voltage effective value is greater than a fourth preset ratio of the rated voltage.

[0077] Preferably, the first preset ratio is 1.2, the second preset ratio is 0.1, the third preset ratio is 0.2, and the fourth preset ratio is 0.05.

[0078] From the above description, it can be seen that the embodiment of the present invention provides a method for preventing the influence of voltage loop abnormality on positive sequence low voltage protection, which has the following technical effects compared with the prior art:

[0079] 1) The present invention adds a logic judgment of positive sequence low voltage and increases the reliability of the positive sequence low voltage protection function;

[0080] 2) The present invention uses the voltage and current of the protected equipment itself for logical discrimination, thereby improving the sensitivity and reliability of the positive sequence low voltage protection function;

[0081] 3) The present invention adds a positive-sequence low-voltage locking function logic, which can effectively prevent the positive-sequence low-voltage protection from incorrect action when the voltage circuit is abnormal, thereby improving the reliability of the positive-sequence low-voltage protection function.

[0082] Embodiment 2

[0083] Figure 3 Schematic diagram of a system for preventing voltage loop abnormality from affecting positive sequence low voltage protection according to an embodiment of the present invention, which is applied to positive sequence low voltage protection of power systems. Figure 3 As shown, the system includes: an acquisition module 10, a determination module 20, a judgment module 30 and an action module 40.

[0084] An acquisition module 10 is used to acquire three-phase voltage acquisition data and three-phase current acquisition data of a protected device of positive sequence low voltage protection;

[0085] A determination module 20, for determining a three-phase voltage effective value and a three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data;

[0086] The judging module 30 is used to judge whether the target starting condition of the positive sequence low voltage protection is met based on the three-phase voltage effective value and the three-phase current effective value; the target starting condition includes the positive sequence voltage effective value judgment condition, the positive sequence low voltage once existed judgment condition and the positive sequence low voltage protection locking judgment condition;

[0087] The action module 40 is used to control the positive sequence low voltage protection to act if the duration for which the positive sequence low voltage protection meets the target start condition exceeds the preset action time of the positive sequence low voltage protection.

[0088] The present invention further provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method provided in the embodiment of the present invention when executing the computer program.

[0089] The present invention also provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the method provided in the embodiment of the present invention is implemented.

[0090] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0091] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preventing voltage circuit abnormality from affecting positive sequence low voltage protection, characterized in that: Positive sequence low voltage protection applied to power system; including: Acquire three-phase voltage acquisition data and three-phase current acquisition data of the protected equipment of the positive-sequence low voltage protection; Determine the three-phase voltage effective value and the three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data; Based on the three-phase voltage effective value and the three-phase current effective value, judging whether the target start condition of the positive sequence low voltage protection is met; the target start condition includes a positive sequence voltage effective value judgment condition, a positive sequence low voltage once existed judgment condition and a positive sequence low voltage protection lock judgment condition; If the duration for which the positive-sequence low-voltage protection meets the target start-up condition exceeds the preset action time of the positive-sequence low-voltage protection, the positive-sequence low-voltage protection is controlled to act.

2. The method according to claim 1, characterized in that: The three-phase voltage effective value includes: positive sequence voltage effective value, negative sequence voltage effective value, zero sequence voltage effective value, maximum phase-to-phase voltage effective value, and minimum phase-to-phase voltage effective value; The three-phase current effective values ​​include: a maximum phase current effective value and a negative sequence current effective value.

3. The method according to claim 2, characterized in that: The positive sequence voltage effective value determination condition includes: Determining whether the positive-sequence voltage effective value is less than a preset positive-sequence low voltage function threshold; If yes, then the positive sequence voltage effective value judgment condition is met.

4. The method according to claim 2, characterized in that: The positive sequence low voltage once existed judgment condition includes: first judgment condition, second judgment condition, third judgment condition and return condition; wherein, The first discrimination condition includes: the positive sequence voltage effective value is continuously greater than a preset positive sequence low voltage function threshold; The second judgment condition includes: the protection function of the positive sequence low voltage protection is not actuated; The third judgment condition includes: the protection function of the positive sequence low voltage protection is put into operation; If the first discrimination condition, the second discrimination condition and the third discrimination condition are satisfied simultaneously for more than a first preset time, then under the return condition, the positive sequence low voltage once existed discrimination condition is satisfied.

5. The method according to claim 4, characterized in that: The return conditions include: After the protection function of the positive sequence low voltage protection is activated, the positive sequence low voltage has been under pressure judgment condition returns after a second preset time; After the protection function of the positive-sequence low voltage protection is exited, the positive-sequence low voltage once existed judgment condition is immediately returned.

6. The method according to claim 2, characterized in that: The positive sequence low voltage protection lockout judgment condition includes: if the lockout judgment criterion of the positive sequence low voltage protection is not satisfied, then the positive sequence low voltage protection lockout judgment condition is satisfied; wherein, The locking criteria include: locking condition judgment logic for abnormal three-phase voltage circuit, locking condition judgment logic for abnormal single-phase voltage circuit, locking condition judgment logic for abnormal two-phase voltage circuit and negative sequence voltage locking condition judgment logic; When any one of the three-phase voltage circuit abnormality locking condition judgment logic, the single-phase voltage circuit abnormality locking condition judgment logic, the two-phase voltage circuit abnormality locking condition judgment logic and the negative-sequence voltage locking condition judgment logic is met, the locking criterion is met; otherwise, the locking criterion is not met.

7. The method according to claim 6, characterized in that: The locking condition judgment logic of the abnormal three-phase voltage circuit includes: the maximum phase current effective value is less than a first preset ratio of the rated current, and the maximum phase-to-phase voltage effective value is less than a second preset ratio of the rated voltage value; The lockout condition judgment logic of the single-phase voltage circuit abnormality includes: the zero-sequence voltage effective value is greater than a second preset ratio of the rated voltage value, and the difference between the maximum phase-to-phase voltage effective value and the minimum phase-to-phase voltage effective value is greater than a third preset ratio of the rated voltage value; The locking condition judgment logic of the abnormal two-phase voltage circuit includes: the minimum phase-to-phase voltage effective value is less than a third preset ratio of the rated voltage value, and the zero-sequence voltage effective value is greater than a second preset ratio of the rated voltage value; The negative sequence voltage locking condition judgment logic includes: the negative sequence current effective value is less than a second preset ratio of the rated current, and the negative sequence voltage effective value is greater than a fourth preset ratio of the rated voltage.

8. A system for preventing voltage circuit abnormality from affecting positive sequence low voltage protection, characterized in that: Positive sequence low voltage protection applied to power system; including: acquisition module, determination module, judgment module and action module; wherein, The acquisition module is used to acquire the three-phase voltage acquisition data and the three-phase current acquisition data of the protected equipment of the positive sequence low voltage protection; The determination module is used to determine the three-phase voltage effective value and the three-phase current effective value based on the three-phase voltage acquisition data and the three-phase current acquisition data; The judgment module is used to judge whether the target start condition of the positive sequence low voltage protection is met based on the three-phase voltage effective value and the three-phase current effective value; the target start condition includes the positive sequence voltage effective value judgment condition, the positive sequence low voltage once existed judgment condition and the positive sequence low voltage protection lock judgment condition; The action module is used to control the positive-sequence low-voltage protection to act if the duration for which the positive-sequence low-voltage protection meets the target start-up condition exceeds the preset action time of the positive-sequence low-voltage protection.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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