Single-phase earth fault removal method and device

Abstract

The invention provides a single-phase earth fault removal method and device, and relates to the field of fault processing, and the method comprises the steps: obtaining the transient component of each line in a power supply system; comparing the transient components of the lines, and taking the line with the maximum amplitude of the transient component as a first pre-selected line; acquiring a transient phase of each line in the power supply system; comparing the transient phase of each line, and taking a line with a different transient phase as a second pre-selected line; acquiring transient power of each line in the power supply system; comparing the transient power of each line, and taking a line with a direction different from that of other transient power as a third preselected line; and determining a fault line in the first pre-selected line, the second pre-selected line and the third pre-selected line, and executing a cutting action of the fault line. According to the method and the device for removing the single-phase earth fault, the single-phase earth fault line can be quickly determined, and the fault line can be removed in time.

Description

Technical Field

[0001] The present disclosure relates to the technical field of fault processing, and in particular to a method and device for removing a single-phase grounding fault. Background Art

[0002] In order to build an energy system with multiple energy forms, increase the proportion of non-fossil energy in the energy consumption structure, and gradually achieve the goal of "carbon peak and carbon neutrality", a new water-photovoltaic complementary power generation model with hydropower station power generation as the main power generation and photovoltaic power station power generation as the auxiliary power generation is constantly emerging, and the proportion of photovoltaic installed capacity is constantly increasing.

[0003] The operation mode of the neutral point ungrounded power supply system allows short-term (2h) fault operation when single-phase grounding occurs, which greatly improves the power supply reliability of the system. However, with the expansion of photovoltaic stations and the increase of outgoing cables, the system's ground capacitance current increases sharply. After single-phase grounding, the current flowing through the fault point is large, the arc is not easy to extinguish, and intermittent arc grounding overvoltage is easily generated. At the same time, due to the saturation of the electromagnetic voltage transformer core, it is easy to cause resonant overvoltage, resulting in a significant increase in the accident trip rate.

[0004] Therefore, it is necessary to study a single-phase grounding fault removal strategy based on a neutral point ungrounded power supply system, which can quickly identify the faulty line and remove the faulty line in time to ensure the safe and stable operation of non-faulty transmission equipment in the power supply system. Summary of the invention

[0005] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0006] To this end, the object of the present disclosure is to provide a method and device for clearing a single-phase grounding fault.

[0007] To achieve the above-mentioned purpose, the first aspect of the present disclosure provides a single-phase grounding fault removal method, which is used in a neutral point ungrounded power supply system, and the method includes: obtaining the transient components of each line in the power supply system; comparing the transient components of each line, and taking the line with the largest transient component amplitude as the first pre-selected line; obtaining the transient phase of each line in the power supply system; comparing the transient phase of each line, and taking the line with a different transient phase from other lines as the second pre-selected line; obtaining the transient power of each line in the power supply system; comparing the transient power of each line, and taking the line with a different transient power direction from other lines as the third pre-selected line; determining the faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line, and performing the removal action of the faulty line.

[0008] Optionally, determining a faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line includes: when the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, taking the line as the faulty line; and performing a removal action of the faulty line.

[0009] Optionally, determining the faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line includes: when two pre-selected lines among the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, taking the line as the faulty line and taking the remaining pre-selected lines as alternative lines; executing a cutting action of the faulty line and executing an alarm indication action of the alternative line.

[0010] Optionally, determining the faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line includes: when the first pre-selected line, the second pre-selected line and the third pre-selected line are different lines, taking the second pre-selected line as the faulty line, and taking the first pre-selected line and the third pre-selected line as backup lines respectively; executing a cutting action of the faulty line, and executing an alarm indication action of the first pre-selected line and the third pre-selected line.

[0011] Optionally, the method further includes: when the transient phases of all lines are the same, taking a bus in the power supply system as the fault line, and performing a cutting action on the fault line.

[0012] Optionally, the method further includes: when the transient power directions of all lines are the same, taking the bus in the power supply system as the fault line, and performing a cutting action on the fault line.

[0013] Optionally, the acquiring the transient power of each line in the power supply system includes: acquiring the transient power of the line according to the transient component of the line.

[0014] According to a second aspect of the present disclosure, there is provided a single-phase grounding fault removal device, which is used in a neutral point ungrounded power supply system, and comprises: a collection unit, which is used to obtain the transient component, transient phase and transient power of each line in the power supply system; a comparison unit, which is used to compare the transient component of each line, the transient phase of each line and the transient power of each line; a processing unit, which is used to take the line with the largest amplitude of the transient component as the first pre-selected line, take the line with different transient phases from other lines as the second pre-selected line, and take the line with different transient power directions from other lines as the third pre-selected line, and determine the faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line; and an execution unit, which is used to execute the removal action of the faulty line.

[0015] The third aspect of the present disclosure provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the single-phase ground fault removal method provided in the first aspect of the present disclosure is implemented.

[0016] A fourth aspect of the present disclosure provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the single-phase ground fault removal method provided in the first aspect of the present disclosure is implemented.

[0017] The technical solution provided by the present disclosure may have the following beneficial effects: By acquiring and comparing the transient components of each line in the power supply system, and taking the line with the largest transient component amplitude as the first pre-selected line, the transient amplitude ratio strategy is realized; by acquiring and comparing the transient phases of each line in the power supply system, and taking the line with a different transient phase from other lines as the second pre-selected line, the transient phase ratio strategy is realized; by acquiring and comparing the transient power of each line in the power supply system, and taking the line with a different transient power direction from other lines as the third pre-selected line, the transient power direction strategy is realized. Thus, the fault line is determined among the first pre-selected line, the second pre-selected line and the third pre-selected line determined by the three different strategies, and the influence of the zero-sequence unbalanced current caused by the load current on the zero-sequence current sampling is fully considered, and the single-phase grounding fault line can be quickly determined, and the fault line can be cut off in time, thereby ensuring the safe and stable operation of non-fault transmission equipment in the neutral point ungrounded power supply system, which has broad promotion value and application prospects.

[0018] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 It is a flow chart of a single-phase grounding fault removal method proposed in an embodiment of the present disclosure; DETAILED DESCRIPTION Embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and are not to be construed as limitations of the present disclosure. On the contrary, the embodiments of the present disclosure include all changes, modifications, and equivalents that fall within the spirit and connotation of the appended claims.

[0020] like Figure 1 As shown, the embodiment of the present disclosure provides a single-phase grounding fault removal method for a neutral point ungrounded power supply system, comprising: S1: Obtain the transient components of each line in the power supply system; S2: compare the transient components of each line, and take the line with the largest transient component amplitude as the first pre-selected line; S3: Obtain the transient phase of each line in the power supply system; S4: comparing the transient phases of the various lines, and taking the line with a different transient phase from the others as the second pre-selected line; S5: Obtain the transient power of each line in the power supply system; S6: comparing the transient powers of the various lines, and taking the line with a different transient power direction from the other lines as the third pre-selected line; S7: Determine a faulty line from the first pre-selected line, the second pre-selected line, and the third pre-selected line, and perform a removal operation on the faulty line.

[0021] It can be understood that the transient amplitude ratio strategy is realized by acquiring and comparing the transient components of each line in the power supply system, and taking the line with the largest transient component amplitude as the first pre-selected line; the transient phase ratio strategy is realized by acquiring and comparing the transient phases of each line in the power supply system, and taking the line with a different transient phase from other lines as the second pre-selected line; the transient power direction strategy is realized by acquiring and comparing the transient power of each line in the power supply system, and taking the line with a different transient power direction from other lines as the third pre-selected line. Thus, the fault line is determined among the first pre-selected line, the second pre-selected line and the third pre-selected line determined by the three different strategies, and the influence of the zero-sequence unbalanced current caused by the load current on the zero-sequence current sampling is fully considered, and the single-phase grounding fault line can be quickly determined, and the fault line can be cut off in time, thereby ensuring the safe and stable operation of non-fault transmission equipment in the neutral point ungrounded power supply system, which has broad promotion value and application prospects.

[0022] It should be noted that when a single-phase grounding fault occurs in a neutral point ungrounded power supply system, the current amplitude of the fault line is the largest, the zero-sequence voltage of the fault line suddenly increases, the zero-sequence current phase on the fault line lags behind the zero-sequence voltage by 90°, and the zero-sequence current phase on the non-fault line leads the zero-sequence voltage by 90°. If the zero-sequence voltage phase is taken as the reference phase, the current direction of the fault line is opposite to that of the non-fault line. In addition, the zero-sequence current amplitude gradually increases along the fault line and reaches the maximum at the single-phase grounding fault point in the fault line. Therefore, in the working principle of the single-phase grounding fault removal method in this embodiment, the phase and amplitude characteristics of the transient current at the time of the line grounding fault are extracted to complete the fault line selection judgment, and gradually lock the specific fault point location, so as to quickly remove the grounding fault.

[0023] Among them, the power supply system can be a 35kV system.

[0024] For the transient amplitude ratio strategy, when a single-phase grounding fault occurs in the power supply system, the transient component amplitude of the faulty line is much larger than the transient component of the non-faulty line. Therefore, by comparing the transient component amplitudes and selecting the maximum transient component amplitude, the first pre-selected line can be quickly determined.

[0025] For the transient phase comparison strategy, the transient signal in the frequency band with the maximum transient amplitude of the power supply system is selected for phase comparison, and the line with a transient phase different from other lines is selected as the second pre-selected line.

[0026] For the transient power direction strategy, when a single-phase ground fault occurs in the power supply system, the transient power direction of the fault line is reverse, while the transient power direction of the non-fault line is forward. The zero-sequence relay characteristic angle (ZS) direction element judgment criterion is set as: .

[0027] The first pre-selected line, the second pre-selected line and the third pre-selected line are all pre-selected lines for the fault line. By comparing and analyzing the first pre-selected line, the second pre-selected line and the third pre-selected line, the interference of other factors can be reduced, thereby more accurately determining the fault line.

[0028] The fault line removal action can be set according to actual needs, and there is no limitation to this. For example, a switch is used to disconnect the path between the busbar and the fault line and the path between other lines and the fault line, so that the fault line is removed from the power supply system. After the fault line is removed, further inspection and maintenance of the fault point in the fault line can be carried out.

[0029] In some embodiments, determining a faulty line among the first pre-selected line, the second pre-selected line, and the third pre-selected line comprises: S71: when the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, taking the line as a fault line; S72: Execute the action of disconnecting the faulty line.

[0030] It can be understood that when the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, it indicates that the line judged by the transient amplitude ratio strategy, the line judged by the transient phase comparison strategy and the line judged by the transient power direction strategy are the same line. Therefore, it can be accurately determined that the line is a fault line, and then after executing the fault line cutting action, the safe and stable operation of non-fault transmission equipment in the power supply system can be guaranteed.

[0031] In some embodiments, determining a faulty line among the first pre-selected line, the second pre-selected line, and the third pre-selected line comprises: S701: When two pre-selected lines among the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, the lines are regarded as faulty lines, and the remaining pre-selected lines are regarded as standby lines; S702: Execute the disconnection action of the faulty line and execute the alarm indication action of the alternative line.

[0032] It can be understood that when two of the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, it means that one of the lines judged by the transient amplitude ratio strategy, the line judged by the transient phase ratio strategy and the line judged by the transient power direction strategy may be misjudged due to interference from other factors. Therefore, the same line judged by the two pre-selected lines can also accurately determine the fault location, so that after executing the fault line cutting action, the safe and stable operation of non-fault transmission equipment in the power supply system can be guaranteed. At the same time, the pre-selected line that may be misjudged is used as a backup line, and an alarm indication is given to the backup line. While ensuring the stable operation of the power supply system, the backup line can be used as the key focus line in the subsequent sequence, thereby improving the inspection and maintenance efficiency and operation safety of the power supply system.

[0033] It should be noted that the alarm indication action of the alternative line can be set according to actual needs, and there is no limitation on this. For example, a display can be used to remotely display the passage and position of the alternative line, and an audible and visual alarm can be used to visually indicate the position of the alternative line on site. After the alternative line is indicated, the line can be focused on in the subsequent maintenance work.

[0034] In some embodiments, determining a faulty line among the first pre-selected line, the second pre-selected line, and the third pre-selected line comprises: S7001: When the first pre-selected line, the second pre-selected line and the third pre-selected line are different lines, the second pre-selected line is used as a fault line, and the first pre-selected line and the third pre-selected line are used as standby lines respectively; S7002: Execute the disconnection action of the faulty line, and execute the alarm indication action of the first pre-selected line and the third pre-selected line.

[0035] It can be understood that when the first pre-selected line, the second pre-selected line and the third pre-selected line are different lines, it means that among the lines judged by the transient amplitude ratio strategy, the lines judged by the transient phase ratio strategy and the lines judged by the transient power direction strategy, the first pre-selected line and the third pre-selected line may be misjudged due to interference from other factors. Therefore, taking the second pre-selected line as the fault line can also accurately determine the fault location, so that after executing the fault line cutting action, the safe and stable operation of non-fault transmission equipment in the power supply system can be guaranteed. At the same time, the first pre-selected line and the third pre-selected line that may be misjudged are taken as alternative lines, and alarm indications are given to the alternative lines. While ensuring the stable operation of the power supply system, the alternative lines can be used as the key focus lines in the subsequent sequence, thereby improving the inspection and maintenance efficiency and operation safety of the power supply system.

[0036] In some embodiments, the method further includes: when the transient phases of all lines are the same, treating the bus in the power supply system as a fault line and performing a fault line removal action.

[0037] It can be understood that when the transient phases of all lines are the same, it indicates that the lines in the power supply system have the same fault problem. Therefore, it can be inferred that the common bus of each line has a fault. Therefore, directly taking the bus in the power supply system as the fault line can achieve efficient determination of the fault line, and after executing the fault line cutting action, it can ensure the safe and stable operation of non-fault transmission equipment in the power supply system.

[0038] It should be noted that when a single-phase grounding fault occurs in the busbar in the power supply system, it will cause all lines in the power supply system to fail, and the probability of all lines failing at the same time is extremely low. Therefore, it can be accurately determined that the busbar in the power supply system has a fault.

[0039] In some embodiments, the method further includes: when the transient power directions of all lines are the same, treating the bus in the power supply system as a fault line and performing a fault line removal action.

[0040] It can be understood that when the transient power directions of all lines are the same, it indicates that the lines in the power supply system have the same fault problem. Therefore, it can be inferred that the common bus of each line has a fault. Therefore, directly taking the bus in the power supply system as the fault line can achieve efficient determination of the fault line, and after executing the fault line cutting action, it can ensure the safe and stable operation of non-fault transmission equipment in the power supply system.

[0041] It should be noted that when a single-phase grounding fault occurs on the busbar in the power supply system, both the transient phase comparison strategy and the transient power direction strategy become invalid.

[0042] In some embodiments, obtaining the transient power of each line in the power supply system includes: S51: Obtaining the transient power of the line according to the transient component of the line.

[0043] It is understandable that transient components and transient power are closely related in the working conditions of circuits and electrical equipment. The change of transient components is one of the main reasons for transient power fluctuations. At the same time, the fluctuation of transient power will in turn affect the transient components in the circuit. Therefore, determining the transient power based on the transient components of the line can ensure accurate judgment of the transient power direction strategy.

[0044] It should be noted that the calculation of transient components mainly focuses on temporary changes in system status and does not directly involve power calculation. The calculation of transient power needs to be analyzed in combination with the changes in instantaneous voltage and current, and the transient component is only used as an auxiliary reference for transient power calculation.

[0045] The disclosed embodiment also proposes a ground fault removal device for a single-phase neutral point ungrounded power supply system, comprising: a collection unit, a comparison unit, a processing unit and an execution unit, the collection unit is used to obtain the transient component, transient phase and transient power of each line in the power supply system, the comparison unit is used to compare the transient component of each line, the transient phase of each line and the transient power of each line, the processing unit is used to take the line with the largest transient component amplitude as the first pre-selected line, the line with a different transient phase from other lines as the second pre-selected line, and the line with a different transient power direction from other lines as the third pre-selected line, and determine the faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line, and the execution unit is used to execute the removal action of the faulty line.

[0046] It can be understood that the transient amplitude ratio strategy is realized by acquiring and comparing the transient components of each line in the power supply system, and taking the line with the largest transient component amplitude as the first pre-selected line; the transient phase ratio strategy is realized by acquiring and comparing the transient phases of each line in the power supply system, and taking the line with a different transient phase from other lines as the second pre-selected line; the transient power direction strategy is realized by acquiring and comparing the transient power of each line in the power supply system, and taking the line with a different transient power direction from other lines as the third pre-selected line. Thus, the fault line is determined among the first pre-selected line, the second pre-selected line and the third pre-selected line determined by the three different strategies, and the influence of the zero-sequence unbalanced current caused by the load current on the zero-sequence current sampling is fully considered, and the single-phase grounding fault line can be quickly determined, and the fault line can be cut off in time, thereby ensuring the safe and stable operation of non-fault transmission equipment in the neutral point ungrounded power supply system, which has broad promotion value and application prospects.

[0047] The embodiment of the present disclosure also proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a single-phase ground fault removal method as in the embodiment of the present disclosure is implemented.

[0048] The embodiment of the present disclosure further provides a computer-readable storage medium on which a computer program is stored, wherein when the program is executed by a processor, a single-phase ground fault removal method as in the embodiment of the present disclosure is implemented.

[0049] It should be noted that, in the description of the present disclosure, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0050] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present disclosure includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0051] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0052] Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A single-phase ground fault removal method, characterized in that: The method is used for a neutral point ungrounded power supply system, and the method comprises: Obtaining transient components of each line in the power supply system; Comparing the transient components of the various lines, and taking the line with the largest transient component amplitude as the first pre-selected line; Obtaining the transient phase of each line in the power supply system; Comparing the transient phases of the respective lines, and taking the line with a different transient phase from the other lines as the second pre-selected line; Obtaining the transient power of each line in the power supply system; Comparing the transient powers of the respective lines, and taking the line with a different transient power direction from the other lines as the third pre-selected line; A faulty line is determined among the first pre-selected line, the second pre-selected line and the third pre-selected line, and a removal action of the faulty line is performed.

2. The single-phase grounding fault removal method according to claim 1, characterized in that: The determining a faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line comprises: When the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, taking the line as the fault line; Execute the action of disconnecting the fault line.

3. The single-phase grounding fault removal method according to claim 1, characterized in that: The determining a faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line comprises: When two of the first pre-selected line, the second pre-selected line and the third pre-selected line are the same line, the line is used as the fault line, and the remaining pre-selected line is used as a standby line; The fault line is cut off and the alternative line is alarmed.

4. The single-phase grounding fault removal method according to claim 1, characterized in that: The determining a faulty line among the first pre-selected line, the second pre-selected line and the third pre-selected line comprises: When the first pre-selected line, the second pre-selected line and the third pre-selected line are different lines, the second pre-selected line is used as the faulty line, and the first pre-selected line and the third pre-selected line are used as alternative lines respectively; The fault line is cut off and the first pre-selected line and the third pre-selected line are alarmed.

5. The single-phase grounding fault removal method according to claim 1, characterized in that: The method further comprises: When the transient phases of all lines are the same, the busbar in the power supply system is taken as the fault line, and a cutting action of the fault line is performed.

6. The single-phase grounding fault removal method according to claim 1, characterized in that: The method further comprises: When the transient power directions of all lines are the same, the busbar in the power supply system is taken as the fault line, and the fault line is cut off.

7. The single-phase grounding fault removal method according to claim 1, characterized in that: The acquiring of the transient power of each line in the power supply system comprises: The transient power of the line is obtained according to the transient component of the line.

8. A single-phase ground fault removal device, characterized in that: The device is used in a neutral point ungrounded power supply system, and comprises: A collection unit, the collection unit is used to obtain the transient component, transient phase and transient power of each line in the power supply system; A comparison unit, the comparison unit is used to compare the transient components of each of the lines, the transient phases of each of the lines, and the transient powers of each of the lines; a processing unit, the processing unit being configured to select the line with the largest transient component amplitude as a first pre-selected line, select the line with a different transient phase from the other lines as a second pre-selected line, and select the line with a different transient power direction from the other lines as a third pre-selected line, and determine a faulty line among the first pre-selected line, the second pre-selected line, and the third pre-selected line; An execution unit, wherein the execution unit is used to execute a cutting action of the faulty line.

9. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a single-phase grounding fault removal method as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, a single-phase grounding fault removal method according to any one of claims 1 to 7 is implemented.

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