A small current grounding fault identification and diagnosis system and method based on multiple information sources

Abstract

A system and method for identifying and diagnosing a small current grounding fault based on multiple information sources, the system comprising a current monitoring module, a diagnostic analysis module, a fault identification module and a fault processing module, the current monitoring module being connected to the diagnostic analysis module, the current monitoring module comprising a number of monitoring points arranged on different section lines, the fault identification module being connected to the diagnostic analysis module, and the fault processing module being connected to the fault identification module. The method for identifying and diagnosing a small current grounding fault specifically comprises the following steps: when a zero-sequence current is detected in a corresponding section, the corresponding monitoring point records the zero-sequence current information, compares it with a preset zero-sequence current abnormal threshold, audits it when it exceeds the threshold, performs fault analysis on it after the audit is passed, and finally performs fault processing after the corresponding section line is cut off. The present invention can improve the efficiency of small current grounding fault diagnosis and the reliability of the diagnosis result.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network control, and in particular to a system and method for identifying and diagnosing a small current grounding fault based on multiple information sources. Background Art

[0002] The distribution network is composed of overhead lines, cables, towers, distribution transformers, disconnectors, reactive compensators and some ancillary facilities. As a network that plays an important role in distributing electric energy in the power grid, the distribution network generally adopts a closed-loop design and open-loop operation distribution design method, and its structure is generally radial. When a small current grounding single-phase fault occurs, in order to improve the efficiency of fault resolution, it is necessary to accurately locate the line of the small current grounding single-phase fault. However, due to the increasingly complex structure of the distribution network and the gradual expansion of the line scale, the current method of relying on manual experience to achieve line selection is too inefficient, and it is impossible to quickly and accurately find the corresponding line information and section location point information of the specific fault. The reliability of relying on manual experience for small current grounding fault identification and diagnosis is not high, and it will reduce the processing efficiency of small current grounding fault diagnosis. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a system and method for identifying and diagnosing a small current grounding fault based on multiple information sources.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A small current grounding fault identification and diagnosis system based on multiple information sources includes a current monitoring module, a diagnosis and analysis module, a fault identification module and a fault processing module. The current monitoring module is connected to the diagnosis and analysis module. The current monitoring module includes a plurality of monitoring points arranged on different section lines. The current monitoring module monitors the zero-sequence current information on all section lines through the monitoring points. The diagnosis and analysis module is used to analyze and compare the zero-sequence current information monitored by the current monitoring module to obtain the abnormal situation of the zero-sequence current. The fault identification module is connected to the diagnosis and analysis module. The fault identification module is used to review and judge the abnormal situation of the zero-sequence current and obtain fault analysis information. The fault processing module is connected to the fault identification module. The fault identification module is used to automatically cut off the line according to the fault analysis information and match the corresponding line operation plan.

[0006] Furthermore, the zero-sequence current information includes corresponding time point information recorded in the zero-sequence current information, corresponding line information recorded in the zero-sequence current information, and corresponding position point information recorded in the zero-sequence current information.

[0007] Furthermore, a preset zero-sequence current abnormality threshold is stored in the diagnosis and analysis module, and the diagnosis and analysis module obtains the abnormality of the zero-sequence current by comparing the zero-sequence current value in the zero-sequence current information with the preset zero-sequence current abnormality threshold.

[0008] Furthermore, the small current grounding fault identification and diagnosis system based on multiple information sources also includes an early warning module, which is connected to the fault identification module and the fault processing module at the same time. The early warning module is used to issue an alarm after the fault identification module confirms the fault. The early warning module is also used to send a line operation plan matched by the fault processing module.

[0009] A method for identifying and diagnosing a small current grounding fault based on multiple information sources comprises the following steps:

[0010] Step 1: Each monitoring point monitors the zero-sequence current in the corresponding section in real time. When any monitoring point detects the existence of zero-sequence current in the corresponding section, the corresponding monitoring point records the zero-sequence current information;

[0011] Step 2: The diagnostic analysis module compares the zero-sequence current value in the zero-sequence current information with a preset zero-sequence current abnormality threshold value. If the zero-sequence current value exceeds the preset zero-sequence current abnormality threshold value, the zero-sequence current information is judged to be abnormal, and the zero-sequence current information with the abnormality is transmitted to the fault identification module; if the zero-sequence current value does not exceed the preset zero-sequence current abnormality threshold value, the zero-sequence current information is judged to be unnecessary to be processed, and the corresponding monitoring point continues to perform zero-sequence current monitoring;

[0012] Step three, the fault identification module reviews the abnormal zero-sequence current information, and after the review is passed, performs a fault analysis based on the abnormal zero-sequence current information to obtain the fault analysis information. The fault handling module first cuts off the corresponding section line, and then matches the line operation plan based on the fault analysis information. The operator handles the fault according to the line operation plan.

[0013] Furthermore, the review process of the abnormal zero-sequence current information is as follows: according to the abnormal zero-sequence current information, the position of the zero-sequence current collection monitoring point is determined, and the current is re-collected through the monitoring point. According to the re-collected current information, it is judged whether there is zero-sequence current. If the judgment result is that there is no zero-sequence current, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the judgment result is that there is a zero-sequence current, the re-collected zero-sequence current is compared with the preset zero-sequence current abnormal threshold again. If the re-collected zero-sequence current does not exceed the preset zero-sequence current abnormal threshold, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the re-collected zero-sequence current still exceeds the preset zero-sequence current abnormal threshold, the review passes, and a fault analysis is performed on the abnormal zero-sequence current information.

[0014] Furthermore, the line operation plan includes the line section to be inspected, the location of the fault, the fault type and the fault handling method.

[0015] Furthermore, the fault type includes a small current grounding fault.

[0016] The beneficial effects of the present invention are:

[0017] When a small current grounding fault occurs, a zero-sequence current will be generated at the fault point, and the small current grounding fault can be discovered in time by monitoring and analyzing the zero-sequence current. The line and section where the zero-sequence current is generated can be accurately obtained by obtaining the location of the monitoring point, thereby realizing the precise positioning of the line and section where the small current grounding fault occurs, greatly improving the processing efficiency of the small current grounding fault. The generated zero-sequence voltage is audited, and subsequent fault processing is performed only when the audit is passed. The audit effectively improves the reliability of the small current grounding fault diagnosis results, and prevents the loss caused by the erroneous acquisition of zero-sequence current and the corresponding fault processing. The line can be automatically cut off in time to prevent the expansion of the fault impact, and the line operation plan can be improved for the operating personnel, further improving the processing efficiency of the small current grounding fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 It is a schematic diagram of a process of the present invention.

[0020] Among them: 1. Current monitoring module, 2. Diagnosis and analysis module, 3. Fault identification module, 4. Fault handling module, 5. Early warning module. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0022] Example:

[0023] A small current grounding fault identification and diagnosis system based on multiple information sources, such as Figure 1As shown, it includes a current monitoring module 1, a diagnosis and analysis module 2, a fault identification module 3 and a fault processing module 4. The current monitoring module 1 is connected to the diagnosis and analysis module 2. The current monitoring module 1 includes a plurality of monitoring points arranged on different section lines. The current monitoring module 1 monitors the zero-sequence current information on all section lines through the monitoring points. The diagnosis and analysis module 2 is used to analyze and compare the zero-sequence current information monitored by the current monitoring module 1 to obtain the abnormal situation of the zero-sequence current. The fault identification module 3 is connected to the diagnosis and analysis module 2. The fault identification module 3 is used to review and judge the abnormal situation of the zero-sequence current and obtain fault analysis information. The fault processing module 4 is connected to the fault identification module 3. The fault identification module 3 is used to automatically cut off the line according to the fault analysis information and match the corresponding line operation plan.

[0024] The fault identification module 3 stores line operation plans corresponding to different abnormal conditions of zero-sequence current, and obtains the corresponding line operation plan by matching the zero-sequence current value with the abnormal condition.

[0025] Specifically, the monitoring point collects the zero-sequence current through a zero-sequence current transformer.

[0026] When judging faults and abnormal conditions of zero-sequence current, it is necessary to rely on the zero-sequence current value. The magnitude of the zero-sequence current value can reflect the specific type of fault. The magnitude of the zero-sequence current value is affected by different factors in power systems with different grounding types, so the installation position of the zero-sequence current transformer needs to be adjusted.

[0027] The low-current grounding system is an electric power system that uses an ungrounded neutral point or is grounded through an arc suppression coil. When a ground fault occurs in such a system, the ground fault current is very small and cannot constitute a short circuit. In such a power system, the magnitude of the zero-sequence current is related to the ground phase electromotive force of the power system and the ground capacitance on the line. The zero-sequence current flows out from the fault point and flows back to the earth through the ground capacitance on the line. Therefore, the monitoring point needs to be set with reference to the ground capacitance on the line. And for the collected zero-sequence current, it is necessary to distinguish between non-fault components and fault components. The zero-sequence current of the non-fault component is the current on the ground capacitance of the corresponding line itself, and the zero-sequence current value flowing through the fault component is the sum of the current values ​​on the ground capacitance corresponding to all non-fault components in the power system. If an arc suppression coil is also set on the line, the zero-sequence current value flowing through the fault component is the phase sum of the current value on the ground capacitance corresponding to all non-fault components in the power system and the current value on the inductance in the arc suppression coil.

[0028] The zero-sequence current information includes corresponding time point information recorded in the zero-sequence current information, corresponding line information recorded in the zero-sequence current information, and corresponding position point information recorded in the zero-sequence current information.

[0029] The diagnosis and analysis module 2 stores a preset zero-sequence current abnormality threshold value. The diagnosis and analysis module 2 obtains the abnormality of the zero-sequence current by comparing the zero-sequence current value in the zero-sequence current information with the preset zero-sequence current abnormality threshold value.

[0030] The abnormal threshold of zero-sequence current is different for different equipment and line conditions. And because the actual measurement of zero-sequence current during the normal operation of the power system sometimes measures the existence of zero-sequence current, the existence of zero-sequence current does not affect the normal operation. Therefore, only when the measured zero-sequence current value exceeds the abnormal threshold, there will be a fault risk, which further reduces the risk of misjudgment of faults and improves the reliability of the diagnosis results of small current grounding fault identification.

[0031] It also includes an early warning module 5, which is connected to the fault identification module 3 and the fault processing module 4 at the same time. The early warning module 5 is used to issue an alarm after the fault identification module 3 confirms the fault. The early warning module 5 is also used to display the line operation plan matched by the fault processing module 4.

[0032] The early warning module 5 sends the line operation plan to the operating personnel through WeChat, SMS, etc. After receiving the line operation plan, the operating personnel conducts fault troubleshooting and processing.

[0033] A method for identifying and diagnosing small current grounding faults based on multiple information sources, such as Figure 2 As shown, the following steps are included:

[0034] Step 1: Each monitoring point monitors the zero-sequence current in the corresponding section in real time. When any monitoring point detects the existence of zero-sequence current in the corresponding section, the corresponding monitoring point records the zero-sequence current information;

[0035] Step 2: The diagnostic analysis module 2 compares the zero-sequence current value in the zero-sequence current information with the preset zero-sequence current abnormality threshold. If the zero-sequence current value exceeds the preset zero-sequence current abnormality threshold, it is determined that the zero-sequence current information is abnormal, and the zero-sequence current information with the abnormality is transmitted to the fault identification module 3; if the zero-sequence current value does not exceed the preset zero-sequence current abnormality threshold, it is determined that the zero-sequence current information does not need to be processed, and the corresponding monitoring point continues to monitor the zero-sequence current;

[0036] Step three, the fault identification module 3 reviews the abnormal zero-sequence current information, and after the review is passed, performs a fault analysis based on the abnormal zero-sequence current information to obtain the fault analysis information. The fault handling module 4 first cuts off the corresponding section line, and then matches the line operation plan according to the fault analysis information. The operator handles the fault according to the line operation plan.

[0037] The review process of the abnormal zero-sequence current information is as follows: according to the abnormal zero-sequence current information, the position of the zero-sequence current collection monitoring point is determined, and the current is re-collected through the monitoring point. It is judged whether there is zero-sequence current according to the re-collected current information. If the judgment result is that there is no zero-sequence current, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the judgment result is that there is a zero-sequence current, the re-collected zero-sequence current is compared with the preset zero-sequence current abnormal threshold again. If the re-collected zero-sequence current does not exceed the preset zero-sequence current abnormal threshold, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the re-collected zero-sequence current still exceeds the preset zero-sequence current abnormal threshold, the review passes, and a fault analysis is performed on the abnormal zero-sequence current information.

[0038] The review of zero-sequence current information can effectively eliminate the mismeasurement of zero-sequence current and the errors caused by measuring zero-sequence current. When the zero-sequence current transformer mismeasures the current on the conductor other than the three-phase line, it may also be mistaken for the generation of zero-sequence current. Re-measurement of the zero-sequence current transformer can effectively eliminate the mismeasurement.

[0039] The line operation plan includes the line section to be inspected, the location of the fault, the fault type and the fault handling method.

[0040] The fault type includes a small current ground fault.

[0041] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A small current grounding fault identification and diagnosis system based on multiple information sources, characterized in that: It includes a current monitoring module, a diagnosis and analysis module, a fault identification module and a fault processing module. The current monitoring module is connected to the diagnosis and analysis module. The current monitoring module includes a plurality of monitoring points arranged on different section lines. The current monitoring module monitors the zero-sequence current information on all section lines through the monitoring points. The diagnosis and analysis module is used to analyze and compare the zero-sequence current information monitored by the current monitoring module to obtain the abnormal situation of the zero-sequence current. The fault identification module is connected to the diagnosis and analysis module. The fault identification module is used to review and judge the abnormal situation of the zero-sequence current and obtain the fault analysis information. The fault processing module is connected to the fault identification module. The fault identification module is used to automatically cut off the line according to the fault analysis information and match the corresponding line operation plan; Fault identification and diagnosis include the following steps: Step 1: Each monitoring point monitors the zero-sequence current in the corresponding section in real time. When any monitoring point detects the existence of zero-sequence current in the corresponding section, the corresponding monitoring point records the zero-sequence current information; Step 2: The diagnostic analysis module compares the zero-sequence current value in the zero-sequence current information with a preset zero-sequence current abnormality threshold value. If the zero-sequence current value exceeds the preset zero-sequence current abnormality threshold value, the zero-sequence current information is judged to be abnormal, and the zero-sequence current information with the abnormality is transmitted to the fault identification module; if the zero-sequence current value does not exceed the preset zero-sequence current abnormality threshold value, the zero-sequence current information is judged to be unnecessary to be processed, and the corresponding monitoring point continues to perform zero-sequence current monitoring; Step 3: The fault identification module reviews the abnormal zero-sequence current information, and after the review is passed, performs fault analysis based on the abnormal zero-sequence current information to obtain fault analysis information. The fault handling module first cuts off the corresponding section line, and then matches the line operation plan based on the fault analysis information. The operator handles the fault according to the line operation plan. The review process of the abnormal zero-sequence current information is as follows: according to the abnormal zero-sequence current information, the position of the zero-sequence current collection monitoring point is determined, and the current is re-collected through the monitoring point. It is judged whether there is zero-sequence current according to the re-collected current information. If the judgment result is that there is no zero-sequence current, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the judgment result is that there is a zero-sequence current, the re-collected zero-sequence current is compared with the preset zero-sequence current abnormal threshold again. If the re-collected zero-sequence current does not exceed the preset zero-sequence current abnormal threshold, the review fails, and the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; if the re-collected zero-sequence current still exceeds the preset zero-sequence current abnormal threshold, the review passes, and a fault analysis is performed on the abnormal zero-sequence current information.

2. A small current grounding fault identification and diagnosis system based on multiple information sources according to claim 1, characterized in that: The zero-sequence current information includes corresponding time point information recorded in the zero-sequence current information, corresponding line information recorded in the zero-sequence current information, and corresponding position point information recorded in the zero-sequence current information.

3. The small current grounding fault identification and diagnosis system based on multiple information sources according to claim 1 is characterized in that: The diagnosis and analysis module stores a preset zero-sequence current abnormality threshold value, and the diagnosis and analysis module obtains the abnormality of the zero-sequence current by comparing the zero-sequence current value in the zero-sequence current information with the preset zero-sequence current abnormality threshold value.

4. The small current grounding fault identification and diagnosis system based on multiple information sources according to claim 1 is characterized in that: It also includes an early warning module, which is connected to the fault identification module and the fault processing module at the same time. The early warning module is used to issue an alarm after the fault identification module confirms the fault. The early warning module is also used to display the line operation plan matched by the fault processing module.

5. A method for identifying and diagnosing small current grounding faults based on multiple information sources, characterized in that: The following steps are involved: Step 1: Each monitoring point monitors the zero-sequence current in the corresponding section in real time. When any monitoring point detects the existence of zero-sequence current in the corresponding section, the corresponding monitoring point records the zero-sequence current information; Step 2: The diagnostic analysis module compares the zero-sequence current value in the zero-sequence current information with a preset zero-sequence current abnormality threshold. If the zero-sequence current value exceeds the preset zero-sequence current abnormality threshold, it is determined that the zero-sequence current information is abnormal, and the abnormal zero-sequence current information is transmitted to the fault identification module. If it does not exceed, it is determined that the zero-sequence current information does not need to be processed, and the corresponding monitoring point continues to monitor the zero-sequence current; Step three, the fault identification module reviews the abnormal zero-sequence current information, and after the review is passed, performs a fault analysis based on the abnormal zero-sequence current information to obtain the fault analysis information. The fault handling module first cuts off the corresponding section line, and then matches the line operation plan based on the fault analysis information. The operator handles the fault according to the line operation plan.

6. The method for identifying and diagnosing a small current grounding fault based on multiple information sources according to claim 5 is characterized in that: The process of reviewing the abnormal zero-sequence current information is as follows: determining the location of the zero-sequence current collection monitoring point according to the abnormal zero-sequence current information, and re-collecting the current through the monitoring point, judging whether there is zero-sequence current according to the re-collected current information, and if the judgment result is that there is no zero-sequence current, the review fails, the abnormal zero-sequence current information is not processed, and the monitoring point continues to monitor the zero-sequence current; If the result of the judgment is that there is a zero-sequence current, the re-collected zero-sequence current is compared with the preset zero-sequence current abnormal threshold value. If the re-collected zero-sequence current does not exceed the preset zero-sequence current abnormal threshold value, the audit fails, and the zero-sequence current information with the abnormality is not processed, and the monitoring point continues to monitor the zero-sequence current; If the re-collected zero-sequence current still exceeds the preset zero-sequence current abnormal threshold, the review is passed and a fault analysis is performed on the abnormal zero-sequence current information.

7. The method for identifying and diagnosing a small current grounding fault based on multiple information sources according to claim 5 is characterized in that: The line operation plan includes the line section to be inspected, the location of the fault, the fault type and the fault handling method.

8. The method for identifying and diagnosing a small current grounding fault based on multiple information sources according to claim 7 is characterized in that: The fault type includes a small current ground fault.

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