CN-115856551-B - Multi-point injection type cable partial discharge verification method, device and system

CN115856551BCN 115856551 BCN115856551 BCN 115856551BCN-115856551-B

Abstract

The invention provides a multi-point injection type cable partial discharge verification method, device and system, which belong to the technical field of electric power safety, and comprise the following steps: determining an injection signal type, injection signal parameters and a target injection point according to the verification purpose, and injecting the injection signal into the cable according to the target injection point, wherein the injection signal type comprises a partial discharge signal, an interference signal and a reflection analog signal, then acquiring a positioning result after the positioning device positions the partial discharge signal, determining a distance detection value between the injection point of the partial discharge signal and the positioning device according to the positioning result, and finally determining a verification result of the positioning precision of the positioning device according to a comparison result of the distance detection value and an actual distance value. The invention can accurately detect the identification and positioning capability of the positioning device to the partial discharge signal.

Inventors

SU JINGANG
ZHANG PENG
PANG XIANHAI
WEI LIQIANG
HUANG XINGWANG

Assignees

国网河北省电力有限公司电力科学研究院
国家电网有限公司
国网河北能源技术服务有限公司

Dates

Publication Date: 20260512
Application Date: 20221227

Claims (9)

1. The multi-point injection type cable partial discharge verification method is characterized by comprising the following steps of: determining an injection signal type, an injection signal parameter and a target injection point according to the verification purpose, and injecting the injection signal into the cable according to the target injection point, wherein the injection signal type comprises a partial discharge signal, an interference signal and a reflection analog signal; Obtaining a positioning result after the positioning device positions the partial discharge signal, and determining a distance detection value between an injection point of the partial discharge signal and the positioning device according to the positioning result; Determining a verification result of the positioning accuracy of the positioning device according to the comparison result of the distance detection value and the distance actual value; the determining the injection signal type, the injection signal parameters and the target injection point according to the verification purpose comprises: when the verification purpose is long-distance simulation verification, determining that the corresponding injection signal types are partial discharge signals and reflection simulation signals, acquiring setting parameters of a second partial discharge signal and the reflection simulation signals, and setting two target injection points; wherein the target injection points include a partial discharge signal injection point and a reflected analog signal injection point.
2. The multi-point injection type cable partial discharge verification method according to claim 1, wherein the determining the injection signal type, the injection signal parameter and the target injection point according to the verification purpose comprises: When the verification purpose is to overcome the verification of the environmental interference capability, determining that the corresponding injection signal types are partial discharge signals and interference signals, acquiring setting parameters of a first partial discharge signal and the interference signals, and setting two or more target injection points; wherein the target injection points include one partial discharge signal injection point and one or more disturbance signal injection points.
3. The method for checking partial discharge of a multi-point injection type cable according to claim 2, wherein the acquiring the setting parameters of the first partial discharge signal and the interference signal comprises: acquiring a set value of the rising edge and the amplitude of the first partial discharge signal; Acquiring one or more of the type, rising edge set value, falling edge set value, frequency set value and amplitude set value of the interference signal; Wherein the types of the interference signals include one or more of unipolar pulses, monopulse noise signals, multipulse oscillation signals, and continuous high frequency sine wave signals.
4. The multi-point injection type cable partial discharge verification method according to claim 2, wherein the first partial discharge signal and the interference signal are synchronously injected into a cable.
5. The method of claim 1, wherein the obtaining the set parameters of the second partial discharge signal and the reflected analog signal comprises: Acquiring the second partial discharge signal and the reflection analog signal of the same waveform; the ratio of the amplitude of the reflected analog signal to the amplitude of the second partial discharge signal is less than 1 and satisfies a preset range.
6. The multi-point injection type cable partial discharge verification method according to claim 1, wherein the second partial discharge signal is injected and the reflection analog signal is injected after a set time interval; the set time interval is determined according to the target simulation distance corresponding to the long-distance simulation.
7. The method for checking partial discharge of a multi-point injection type cable according to claim 1, wherein the determining a check result of positioning accuracy of the positioning device according to a comparison result of the distance detection value and the distance actual value comprises: the distance detection value and the distance actual value are subjected to difference to obtain a positioning error value; and when the positioning error value meets a preset positioning error range, judging that the verification result is accurate.
8. A multi-point injection type cable partial discharge verification device, comprising: The signal injection module is used for determining an injection signal type, injection signal parameters and a target injection point according to the verification purpose, and injecting the injection signal into the cable according to the target injection point, wherein the injection signal type comprises a partial discharge signal, an interference signal and a reflection analog signal; the signal positioning module is used for acquiring a positioning result after the positioning device positions the partial discharge signal, and determining a distance detection value between an injection point of the partial discharge signal and the positioning device according to the positioning result; the verification result determining module is used for determining a verification result of the positioning accuracy of the positioning device according to the comparison result of the distance detection value and the distance actual value; the signal injection module is specifically configured to: when the verification purpose is long-distance simulation verification, determining that the corresponding injection signal types are partial discharge signals and reflection simulation signals, acquiring setting parameters of a second partial discharge signal and the reflection simulation signals, and setting two target injection points; wherein the target injection points include a partial discharge signal injection point and a reflected analog signal injection point.
9. A multi-point injection type cable partial discharge verification system is characterized by comprising the multi-point injection type cable partial discharge verification device, a signal generator, a flexible injection coupling device and a positioning device according to claim 8; wherein the signal generator is used for generating an injection signal according to the injection signal type and the injection signal parameter; The flexible injection coupling device is used for injecting the injection signal into the cable according to the target injection point; The positioning device is used for performing positioning processing on the partial discharge signals to obtain positioning results.

Description

Multi-point injection type cable partial discharge verification method, device and system Technical Field The invention belongs to the technical field of electric power safety, and particularly relates to a multi-point injection type cable partial discharge verification method, device and system. Background The electric power is used as the basic energy source for the relationship national life and is the basis of economic development and social progress. At the end of 2020, the capacity of the power generation equipment in China reaches 20 hundred million kilowatts, and the electricity consumption per year reaches 5000 kilowatt-hours. According to national energy planning prediction, the whole society electricity consumption of China is doubled by 2050 compared with 2018 (6.84 trillion kilowatt-hours in 2018 and 13.6 trillion kilowatt-hours in 2050), and the electricity consumption of people all reaches 9700 kilowatt-hours. With the acceleration of the urban process, the development of renewable energy sources, the demand of power cables is increasing. Cabling is an essential way for the construction of urban power transmission networks, and is known as a 'vessel' of national economy. The rapid construction of the 10kV and 35kV distribution network alternating current cable transmission system with huge usage is a necessary requirement for urban in the new era, and is a key foundation for guaranteeing national life. The cable plays an extremely important role in the electric energy transmission of the modern urban power grid system, and the running state of the cable directly influences the safety and stability of the large-scale electric system. The design life of the cable is generally 20 to 30 years, but the cable in actual operation often induces permanent faults due to local latent defects such as local degradation or breakage of insulation, and once the cable faults occur, the cable faults can cause shutdown and even out of control of a large-scale electrical system, so that serious economic loss and social influence are caused. The power cable in the urban power supply system is laid in a cable trench or directly buried underground, and under the action of temperature, electric stress, mechanical force, moisture, oil quality, organic compounds, alkali, acid, microorganisms and the like, insulation is easy to corrode and permeate to form insulation local defects, meanwhile, the underground power cable is always subjected to insulation damage due to mechanical external force, and finally the cable is permanently failed. It has been investigated that accidents caused by local defects in the insulation of power cables account for about 40% of cable equipment accidents. Therefore, improving the manufacturing and detection level of the power cable insulation local defect detection equipment is a key for guaranteeing the stable operation of the power system. At present, many researches are carried out on detecting the crosslinked polyethylene cable by students at home and abroad by applying the oscillating wave voltage on the cable to test the partial discharge condition of the equipment, so as to evaluate the state of the cable. Compared with the traditional withstand voltage test, the method has the advantages of short action time of the oscillating wave voltage, convenient operation, portability, flexibility, portability and transportation, and can find various defects in the crosslinked polyethylene power cable. In recent years, cable oscillatory wave partial discharge detection devices produced by various manufacturers are also gradually put into the market, and standards of related detection systems are also established. In 2018, the standard 6kV-35kV cable oscillatory wave partial discharge measurement system detection standard of the power industry of the people's republic of China is promulgated, and then a large number of scientific research institutions and the power industry develop corresponding tests according to the standard, but because a relatively precise measuring instrument and system and abundant operation experience are required in the detection process proposed by the system, the verification of each unit on an oscillatory wave detection system is still in a fumbling stage at present, and a standardized verification device is not established yet. In addition, the cable oscillatory wave partial discharge detection device has a plurality of index parameters, only the minimum requirements of partial indexes are specified in the standard, and how to comprehensively discriminate and judge the advantages and disadvantages of the device according to the indexes is not related. Therefore, when the oscillatory wave partial discharge testing instrument is used on site, no accurate judgment basis exists, and the detection work of the oscillatory wave partial discharge of each cable needs to be further perfected. According to the regulation of related standard, the accuracy of partial discharge