Method for sensing single-phase earth fault of power distribution network

Abstract

The invention discloses a method for sensing a single-phase earth fault of a power distribution network, and the method comprises the following steps: S1, real-time monitoring and data collection: monitoring the current, voltage and power of the power distribution network in real time through a sensor, a fault indicator, an intelligent electric meter and a line monitoring device which are disposed in the power distribution network; s2, fault signal identification: when the monitoring equipment detects that asymmetric current or voltage signals appear in the line and the zero-sequence current is obviously increased, identifying a single-phase earth fault as a single-phase earth fault; s3, fault positioning: determining an approximate position of a fault point by using a built-in positioning technology of a fault sensor; and S4, signal analysis and confirmation: after the power distribution network control center or the cloud platform receives the signal sent by the sensor, a data analysis algorithm is utilized to further analyze and confirm the fault type and severity. According to the invention, the comprehensive process of monitoring, analysis and positioning can be realized, and the fault position can be quickly identified and determined, so that measures can be taken in time to recover the normal operation of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of single-phase grounding fault perception in a distribution network, and in particular to a method for perceiving a single-phase grounding fault in a distribution network. Background Art

[0002] As a bridge between the power system and users, the reliability of the distribution network determines the quality and safety of power users. With the continuous progress of the economy and society, the distribution network has shown a trend of expansion in scale and complexity in topology. The single-phase grounding fault problem in the distribution network has also shown the characteristics of unclear fault characteristics and diverse fault conditions. The problem of locating single-phase grounding faults has not been well solved and cannot meet the requirements of economical and reliable operation.

[0003] The existing publication number CN113219300B discloses a single-phase grounding fault sensing method for a distribution network based on the transient and steady-state of phase current, comprising collecting three-phase currents of the distribution network, synthesizing zero-sequence current and calculating fundamental wave amplitude, obtaining a fault signal when a single-phase grounding fault occurs, thereby obtaining the fault occurrence time and the line fault component current; obtaining the fundamental frequency component amplitude and the high-frequency component amplitude of the fault component current, and judging whether the quantitative relationship between the two meets the fault sensing criterion; when the criterion is met, judging that the system has a resistance grounding fault, and using the steady-state characteristics of the fault component current combined with the variance to obtain the fault path positioning result; otherwise, judging that the system has an arc grounding fault, using the transient characteristics of the fault component current combined with the improved S transform to obtain the sampling point at the fault occurrence time and the three-phase current mutation direction to obtain the fault path positioning result; the method can be applied to various types of single-phase grounding faults occurring in the distribution network, and effectively improve the operation reliability of the distribution network.

[0004] Although the existing technology can realize the perception of ground faults, it is unclear how to quickly determine the location of the ground fault, how to determine the nature of the fault, and how to quickly respond to the fault and minimize power outages. Summary of the invention

[0005] The purpose of the present invention is to provide a method for sensing a single-phase grounding fault in a distribution network to solve the problems in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for sensing a single-phase grounding fault in a distribution network, comprising the following steps:

[0007] S1. Real-time monitoring and data collection: Through sensors, fault indicators, smart meters, and line monitoring devices installed in the distribution network, the current, voltage, and power of the power grid are monitored in real time;

[0008] S2. Fault signal identification: When the monitoring equipment detects an asymmetric current or voltage signal in the line, and when the zero-sequence current increases significantly, it is identified as a single-phase grounding fault;

[0009] S3, Fault location: Use the built-in positioning technology of the fault sensor to determine the approximate location of the fault point;

[0010] S4, signal analysis and confirmation: After the distribution network control center or cloud platform receives the signal sent by the sensor, it uses the data analysis algorithm to further analyze and confirm the fault type and severity;

[0011] S5, Fault reporting and notification: After analysis and confirmation, the system automatically generates a fault report and immediately notifies the operation and maintenance personnel or the dispatch center;

[0012] S6, decision support and response;

[0013] S7. On-site verification and processing: The operation and maintenance personnel arrive at the suspected fault point, conduct on-site inspection and verification, confirm the nature of the fault and perform repair work. After the fault is eliminated, the system confirms that it has returned to normal and completes the closed-loop fault processing.

[0014] Preferably, S5 also includes that the operation and maintenance personnel should first confirm the alarm information and check the preliminary information of the time and location of the fault;

[0015] After receiving the alarm, the operation and maintenance personnel should immediately restore the audible alarm to avoid continued interference, and keep a record of the fault, including time, preliminary judgment, and alarm information.

[0016] Preferably, S6 also includes an internal inspection: the operation and maintenance personnel first inspect the electrical equipment inside the substation to see if there are any obvious signs of failure.

[0017] Preferably, S6 also includes external line inspection: if no fault point is found during the inspection within the station, the external line needs to be inspected; the fault scope is gradually narrowed by segmentation, slicing and branching methods, using insulation megohmmeter, pole inspection, fault indicator and transient recording analysis.

[0018] Preferably, when the fault cannot be located directly, with the permission of the dispatcher, a trial power supply should be carried out on the suspected line to observe whether the fault recurs to assist in judgment; once the faulty line is confirmed, the faulty section should be quickly isolated and power supply to the non-faulty part should be restored.

[0019] Preferably, the real-time monitoring and data acquisition in S1 includes an HD-2 distribution network single-phase grounding fault sensor, which can immediately capture abnormal signals when a fault occurs.

[0020] Preferably, S3 adopts a time difference method, an amplitude comparison method or a positioning technology based on wireless communication; the fault sensor sends a text message containing the fault location information to the fault management center via a SIM card, or uploads data in real time via a wireless network.

[0021] Preferably, S4 includes comparing historical data, filtering signals to eliminate false positives, and using machine learning models for intelligent judgment.

[0022] Preferably, the S5 report includes the fault time, location, and possible cause.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This application can realize the comprehensive process of monitoring, analysis and positioning, and can quickly identify and determine the location of the fault so that timely measures can be taken to restore the normal operation of the system; the entire perception step is a closed-loop process, which can achieve rapid response to faults and minimize the impact of power outages. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0028] See also Figure 1 In an embodiment of the present invention, a method for sensing a single-phase grounding fault in a distribution network includes the following steps:

[0029] S1. Real-time monitoring and data acquisition: The current, voltage and power of the power grid are monitored in real time through sensors, fault indicators, smart meters and line monitoring devices installed in the distribution network. Real-time monitoring and data acquisition includes the HD-2 distribution network single-phase ground fault sensor, which can capture abnormal signals immediately when a fault occurs.

[0030] S2. Fault signal identification: When the monitoring device detects an asymmetric current or voltage signal in the line, and when the zero-sequence current increases significantly, it is identified as a single-phase grounding fault; the circuit design inside the sensor can distinguish between normal operation and fault status, such as by detecting specific frequency resonance or transient signals;

[0031] S3, Fault location: Use the built-in positioning technology of the fault sensor to determine the approximate location of the fault point; use the time difference method, amplitude comparison method or positioning technology based on wireless communication; the fault sensor sends a text message containing the fault location information to the fault management center through the SIM card, or uploads data in real time through the wireless network;

[0032] S4, signal analysis and confirmation: After the distribution network control center or cloud platform receives the signal sent by the sensor, it uses the data analysis algorithm to further analyze and confirm the fault type and severity. This includes comparing historical data, filtering signals to eliminate false alarms, and using machine learning models for intelligent judgment.

[0033] S5. Fault reporting and notification: After analysis and confirmation, the system automatically generates a fault report and immediately notifies the operation and maintenance personnel or the dispatch center; the report includes the fault time, location, and possible causes;

[0034] S6, Assisted decision-making and response: The control center formulates corresponding processing strategies based on the received information and the operating status of the power grid, such as arranging personnel for on-site inspection, adjusting the operating mode, and starting fault isolation and recovery procedures;

[0035] S7. On-site verification and processing: The operation and maintenance personnel arrive at the suspected fault point, conduct on-site inspection and verification, confirm the nature of the fault and perform repair work. After the fault is eliminated, the system confirms that it has returned to normal and completes the closed-loop fault processing.

[0036] Preferably, S5 also includes that the operation and maintenance personnel should first confirm the alarm information and check the preliminary information of the time and location of the fault;

[0037] After receiving the alarm, the operation and maintenance personnel should immediately restore the audible alarm to avoid continued interference, and keep a record of the fault, including time, preliminary judgment, and alarm information.

[0038] Preferably, S6 also includes an internal inspection: the operation and maintenance personnel first inspect the electrical equipment inside the substation to see if there are any obvious signs of failure.

[0039] Preferably, S6 also includes external line inspection: if no fault point is found during the inspection within the station, the external line needs to be inspected; the fault scope is gradually narrowed by segmentation, slicing and branching methods, using insulation megohmmeter, pole inspection, fault indicator and transient recording analysis.

[0040] Preferably, when the fault cannot be located directly, with the permission of the dispatcher, a trial power supply should be carried out on the suspected line to observe whether the fault recurs to assist in judgment; once the faulty line is confirmed, the faulty section should be quickly isolated and power supply to the non-faulty part should be restored.

[0041] This application can realize the comprehensive process of monitoring, analysis, and positioning, and can quickly identify and determine the location of the fault so that timely measures can be taken to restore the normal operation of the system; the entire perception step is a closed-loop process, which can achieve rapid response to faults and minimize the impact of power outages.

[0042] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for sensing a single-phase grounding fault in a distribution network, characterized in that: The following steps are involved: S1. Real-time monitoring and data collection: Through sensors, fault indicators, smart meters, and line monitoring devices installed in the distribution network, the current, voltage, and power of the power grid are monitored in real time; S2. Fault signal identification: When the monitoring equipment detects an asymmetric current or voltage signal in the line, and when the zero-sequence current increases significantly, it is identified as a single-phase grounding fault; S3, Fault location: Use the built-in positioning technology of the fault sensor to determine the approximate location of the fault point; S4, signal analysis and confirmation: After the distribution network control center or cloud platform receives the signal sent by the sensor, it uses the data analysis algorithm to further analyze and confirm the fault type and severity; S5, Fault reporting and notification: After analysis and confirmation, the system automatically generates a fault report and immediately notifies the operation and maintenance personnel or the dispatch center; S6, decision support and response; S7. On-site verification and processing: The operation and maintenance personnel arrive at the suspected fault point, conduct on-site inspection and verification, confirm the nature of the fault and perform repair work. After the fault is eliminated, the system confirms that it has returned to normal and completes the closed-loop fault processing.

2. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The S5 also includes that the operation and maintenance personnel should first confirm the alarm information and check the preliminary information of the time and location of the fault; After receiving the alarm, the operation and maintenance personnel should immediately restore the audible alarm to avoid continued interference, and keep a record of the fault, including time, preliminary judgment, and alarm information.

3. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The S6 also includes an internal inspection: the operation and maintenance personnel first inspect the electrical equipment inside the substation to see if there are any obvious signs of failure.

4. A method for sensing a single-phase grounding fault in a distribution network according to claim 3, characterized in that: The S6 also includes external line inspection: if the fault point is not found during the station inspection, the external line needs to be inspected; the fault scope is gradually narrowed by segmentation, slicing, and branching, and insulation megohmmeter, pole inspection, fault indicator, and transient recording analysis are used.

5. A method for sensing a single-phase grounding fault in a distribution network according to claim 4, characterized in that: If the fault cannot be located directly, with the permission of the dispatcher, test power should be supplied to the suspected line to observe whether the fault recurs to assist in judgment; once the faulty line is confirmed, the faulty section should be quickly isolated and power supply to the non-faulty parts should be restored.

6. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The real-time monitoring and data acquisition in S1 includes the HD-2 distribution network single-phase grounding fault sensor, which can immediately capture abnormal signals when a fault occurs.

7. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The S3 adopts a time difference method, an amplitude comparison method or a positioning technology based on wireless communication; the fault sensor sends a text message containing fault location information to the fault management center through a SIM card, or uploads data in real time through a wireless network.

8. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The S4 includes comparison of historical data, signal filtering to eliminate false positives, and intelligent judgment using machine learning models.

9. A method for sensing a single-phase grounding fault in a distribution network according to claim 1, characterized in that: The S5 report includes the fault time, location, and possible cause.

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