CN-122017500-A - Online monitoring method for partial discharge faults of cable branch box

CN122017500ACN 122017500 ACN122017500 ACN 122017500ACN-122017500-A

Abstract

The invention relates to the technical field of power equipment on-line monitoring, and discloses a cable branch box partial discharge fault on-line monitoring method which is used for solving the problems of high false alarm rate, insufficient fault positioning accuracy and weak overhauling directivity of monitoring results in the traditional method; the method comprises the steps of firstly establishing a monitoring session of a target cable branch box, collecting local discharge pulse records, external reference records and accompanying monitoring records, merging events under uniform time caliber for each point record, conducting interference check and working condition freezing rechecking for external reference records and operating working conditions, conducting carrying judgment and real judgment for abnormal events, conducting branch attribution and fault position confirmation by means of branch propagation sequence relations, branch adjacency relations and accessory position relations, conducting rechecking for abnormal events after attribution, conducting state updating and monitoring conclusion output, and achieving identification of local discharge abnormality of the cable branch box, fault branch and fault position judgment.

Inventors

WANG QIJUN
LIU PEITE
NI JIANGWEI
ZHOU KUNLIN
ZHOU WEICONG

Assignees

浙江特意电气有限公司

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (10)

1. The cable branch box partial discharge fault on-line monitoring method is characterized by comprising the following steps of: s1, establishing a monitoring session of a target cable branch box, reading branch circuit relation, accessory distribution, measuring point corresponding relation and current operation working condition of the branch box, and synchronously acquiring partial discharge pulse records, external reference records and accompanying monitoring records of all monitoring points; S2, event merging is carried out on each monitoring point record based on the unified time caliber, and interference checking and working condition freezing rechecking are carried out on abnormal events by combining external reference records and current operation working conditions; S3, carrying out continuous bearing judgment on the abnormal event rechecked through the working condition freezing, and carrying out authenticity judgment according to the response sequence relation, the repeated occurrence relation and the regional concentration condition of the abnormal event among all monitoring points; S4, judging branch attribution of the abnormal event passing the authenticity judgment according to the branch propagation sequence relationship, the branch adjacency relationship and the accessory position relationship, and confirming fault parts along accessory chains of the corresponding branches; s5, continuously rechecking and updating the state of the abnormal event with the attribution judgment completed, and outputting a monitoring conclusion according to the rechecked attribution state.
2. The method for on-line monitoring of partial discharge faults of a cable branch box according to claim 1, wherein the steps of establishing a monitoring session of a target cable branch box, reading branch circuit relations, accessory distribution, measuring point correspondence and current operation conditions of the branch box, and synchronously acquiring partial discharge pulse records, external reference records and accompanying monitoring records of all monitoring points comprise the steps of: when a monitoring session is established, an object file containing a branch accessory chain sequence and a measuring point arrangement relation is called, and a monitoring session record containing a working condition snapshot, a measuring point effectiveness table, an original record cache area and a subsequent bearing record area is generated; calling a branch mapping table, an accessory linked list and a measuring point mapping table, receiving a partial discharge pulse record, an external reference record and an accompanying monitoring record according to the caliber of a uniform timestamp, writing the partial discharge pulse record, the external reference record and the accompanying monitoring record into a uniform original acquisition record table, and judging the effectiveness of measuring point access; And when the measuring point is abnormal, the method is switched into a frozen state to be recovered, and is switched into a limited monitoring state under the condition of operation disturbance.
3. The method for online monitoring of partial discharge faults of a cable branch box according to claim 1, wherein event merging is performed on each monitoring point record based on a uniform time caliber, and the method comprises the following steps: Sorting original acquisition records in a current monitoring session according to a uniform time caliber, and generating candidate pulse entries for records which have trigger marks and are judged through measuring point effectiveness; carrying out item association according to an external reference synchronous relationship and an accompanying record matching relationship in a neighboring time window, merging according to a time sequence relationship in the same monitoring session, the same working condition snapshot and the same branch, an adjacent branch or a total reference association range in a merging time window, and generating an abnormal event; when a plurality of measuring points cannot be distinguished in sequence, the Guan Cedian is marked as parallel first-reaching measuring points.
4. The online monitoring method for the partial discharge fault of the cable branch box according to claim 1, wherein the method for conducting interference check and working condition freezing rechecking on the abnormal event by combining the external reference record and the current operation working condition comprises the following steps: performing external disturbance investigation, internal space distribution investigation and working condition freezing rechecking on the abnormal event formed by merging; According to the sequence relation between the external reference point and the first reaching measuring point, the cross-branch distribution condition of the internal triggering measuring point and the concentration condition of the accompanying monitoring area, the interference state of the abnormal event is judged, the operation event, the box door state change, the load change and the environment fluctuation are rechecked by combining the working condition freezing windows before and after the abnormal event, and then the abnormal event is transferred to the freezing observation state or the subsequent continuous carrying judgment according to the rechecking result.
5. The on-line monitoring method for partial discharge faults of a cable branch box according to claim 1, wherein the continuous carrying judgment of abnormal events rechecked by working condition freezing comprises the following steps: Establishing an event bearing table for abnormal events rechecked through working condition freezing, and carrying out event set matching according to a first-reaching measuring point historical sequence, a branch candidate historical sequence, a power frequency phase section historical sequence, an accompanying monitoring area historical sequence and an external reference state historical sequence; When the first reaching measuring points are the same or located in the allowed drift range, the power frequency phase sections are the same or adjacent, the accompanying monitoring areas correspond to the same area or the same accessory section, the branch candidate set has intersection, and the external reference state is not changed into continuous leading, the new abnormal event is merged into the existing event set; When the matching condition is not satisfied, a new event set is created.
6. The method for online monitoring of partial discharge faults of a cable branch box according to claim 1, wherein the method for carrying out authenticity judgment according to response precedence relationship, repeated occurrence relationship and regional concentration condition of abnormal events among monitoring points comprises the following steps: Judging the event set according to the stability of the response sequence relation, the persistence of the repeated occurrence relation and the consistency of the regional concentration condition; When at least two judging dimensions meet the stability condition, converting the event set into a suspected real state; When the external reference state is not dominant, the first reaching measuring point is kept stable, and the repeated occurrence interval does not exceed the interruption threshold value, converting the event set into a formal real state; And (3) rechecking under the parallel first-arrival, weak intermittent anomaly and high disturbance background conditions by combining the accompanying monitoring area, the working condition state and the external reference state to form an authenticity judgment result table.
7. The method for on-line monitoring of partial discharge faults of a cable branch box according to claim 1, wherein for an abnormal event passing the authenticity judgment, the branch attribution judgment is performed according to a branch propagation sequence relationship, a branch adjacency relationship and an attachment position relationship, comprising: Calling a branch propagation sequence template established according to the branch mapping relation, the measuring point mapping relation, the accessory chain position relation and the stable triggering sequence under the normal working condition, and carrying out consistency comparison on a first arrival measuring point historical sequence, a triggering measuring point set historical sequence and an accompanying monitoring area historical sequence of an event set in a plurality of observation rounds to determine a main candidate branch; When adjacent candidate branches coexist, conflict judgment is carried out according to the first arrival times difference, the accompanying region concentration times difference and the historical continuous recurrence times difference, and formal branch attribution is formed when the event set reaches a formal real state and a plurality of continuous observation rounds of main candidate branches are consistent.
8. The method for on-line monitoring of partial discharge faults of a cable breakout box according to claim 1, wherein the fault location confirmation is performed along an accessory chain of a corresponding branch, and comprises: layering and positioning the abnormal event along the accessory chain of the attribution branch according to the position relation of the accessory segment in the object file, the accompanying monitoring sensitive area and the relative distance relation between the accessory segment and each measuring point; comparing the accessory segments by combining the centralized positions of the accompanying monitoring areas, the arrival sequence of the first arrival measuring point and the total reference point and the continuous centralized positions of the historical abnormal events in the branch, and forming an accessory segment level position conclusion when at least two positioning bases are commonly pointed to the same accessory segment; The lower level part conclusion is reserved when only a single positioning basis is clear, the branch level conclusion is reserved when no clear segment bit exists, and the part conclusion is refined to a specific part level when the attachment segment is clear and the accompanying monitoring area and the first order are further stable in the same attachment segment.
9. The method for online monitoring of partial discharge faults of a cable branch box according to claim 1, wherein continuously rechecking and updating states of abnormal events for which home determination is completed comprises: Establishing a continuous rechecking table, and layering and setting an observation window and a recovery observation threshold value according to the risk level; Continuously rechecking and updating states according to the rechecking consistency, continuous missing duration, external reference states, working condition states, branch attribution stability and fault position stability of the event set in the observation window; the original attribution conclusion is reserved and the risk level is adjusted when the abnormal event is continuously repeated, and the state is switched into a recovery observation state when the abnormal event stops being repeated; And executing rollback rechecking when external reference leading, branch frequent drifting, fault part span jump or long-term abnormal working condition occur, wherein the up-regulation of the risk level in a single observation window is limited in one level.
10. The method for online monitoring of partial discharge faults of a cable branch box according to claim 1, wherein the method for online monitoring of faults of the cable branch box according to the rechecked attribution state output monitoring conclusion comprises the following steps: Generating a formal conclusion record according to the authenticity state after continuous rechecking, the branch attribution, the fault part, the risk level, the current state description, the recommended rechecking time and the recommended treatment time limit, and forming a monitoring conclusion table; adjusting rechecking requirements and treatment suggestions according to corresponding treatment time limits when the risk level progressively changes; And writing corresponding state information into a formal conclusion record and a monitoring conclusion table under the conditions of recovery observation, degradation rechecking, multi-branch decomposition, multi-part decomposition or incomplete data.

Description

Online monitoring method for partial discharge faults of cable branch box Technical Field The invention relates to the technical field of online monitoring of power equipment, in particular to an online monitoring method for partial discharge faults of a cable branch box. Background In the distribution system, the cable branch box is used for realizing cable tapping, connection and operation isolation; the inside of the cable branch box is usually provided with a plurality of branches, cable accessories and a metal closed structure; in the operation process, once partial discharge occurs, insulation aging and joint degradation are easy to cause, and faults can be expanded when serious, so that the online monitoring of the cable branch box without power failure has practical significance; for example, the disclosed invention patent application CN101710166B discloses an on-line monitoring method for partial discharge of a power cable joint, which collects partial discharge signals through a high-frequency sensor and performs interference rejection by combining pulse polarity identification; However, the problems of judging the authenticity of partial discharge abnormality of the cable branch box and accurately determining fault branches and fault parts in the cable branch box which runs without power failure are still difficult to completely solve by the technology, and the problems of multi-path propagation, reflection superposition, coupling influence and the like of partial discharge signals are easy to occur in the cable branch box due to the fact that a plurality of branches and various cable accessories are arranged in the cable branch box, and interference pulses similar to partial discharge are easy to be introduced into operation working condition changes such as external electromagnetic interference, surrounding equipment pulse coupling, load, temperature and humidity change and the like, so that the abnormal signals can be detected or the operation of the cable branch box can be monitored, whether the real branches and the fault parts in the cable branch box are caused by the real partial discharge pulse propagation in the branch box or not can be accurately identified, meanwhile, a stable and uniform judging mode suitable for on-line operation is difficult to be given, the problems of misinformation, misjudgment and inaccuracy and the like are difficult to solve, the problems of on-line monitoring of the cable branch box partial discharge fault caused by the fact that the existing technology cannot meet the requirements of on-line accurate early warning of the partial discharge fault of the cable branch box on-stage fault, on-line fault maintenance and the like, and the problem of on-line fault monitoring of the cable branch box is difficult to be solved. Disclosure of Invention Aiming at the defects of the prior art, the invention provides an online monitoring method for the partial discharge faults of a cable branch box, which solves the problems of higher false alarm rate, insufficient fault positioning accuracy and weak overhauling directivity of monitoring results in the traditional method. In order to achieve the above purpose, the present invention provides the following technical solutions: An online monitoring method for cable branch box partial discharge faults comprises the following steps: s1, establishing a monitoring session of a target cable branch box, reading branch circuit relation, accessory distribution, measuring point corresponding relation and current operation working condition of the branch box, and synchronously acquiring partial discharge pulse records, external reference records and accompanying monitoring records of all monitoring points; S2, event merging is carried out on each monitoring point record based on the unified time caliber, and interference checking and working condition freezing rechecking are carried out on abnormal events by combining external reference records and current operation working conditions; S3, carrying out continuous bearing judgment on the abnormal event rechecked through the working condition freezing, and carrying out authenticity judgment according to the response sequence relation, the repeated occurrence relation and the regional concentration condition of the abnormal event among all monitoring points; S4, judging branch attribution of the abnormal event passing the authenticity judgment according to the branch propagation sequence relationship, the branch adjacency relationship and the accessory position relationship, and confirming fault parts along accessory chains of the corresponding branches; s5, continuously rechecking and updating the state of the abnormal event with the attribution judgment completed, and outputting a monitoring conclusion according to the rechecked attribution state. Preferably, a monitoring session of a target cable branch box is established, a branch circuit relationship, accessory distribution, a measuri