Power cable local discharge on-line monitoring method and device

Abstract

The invention discloses a method and device for on-line monitoring of partial discharge of power cables. A partial discharge sensor is socketed on the grounding wire of the cable, and a resistance voltage divider is installed on the voltage transformer of the substation, and a computer is used to analyze and process the partial discharge statistical analysis, which can Analyze discharge parameters such as maximum discharge capacity, average discharge capacity, number of discharges, discharge phase, skewness, kurtosis, etc., with rich spectrogram display functions, capable of displaying discharge capacity (including maximum discharge capacity and average discharge capacity) and discharge phase Spectrum, discharge frequency and discharge phase spectrum, discharge ellipsogram, discharge volume-discharge frequency-discharge phase three-dimensional spectrum, realize data management through ORACLE, with historical query function, report printing, threshold alarm, remote query and other functions. The device consists of a Rogowski coil partial discharge sensor, a front-end amplifier, a signal cable, a back-end signal conditioner, a resistor divider, a data acquisition card, a digital IO card, and a computer.

Description

technical field [0001] The invention belongs to the technical field of on-line monitoring of power equipment, and in particular relates to a method and a device for on-line monitoring of partial discharge of power cables. Background technique [0002] High voltage cables are an important part of power systems. With the development of high-voltage and ultra-high-voltage transmission lines, power cables have been more and more widely used due to their unique technical advantages. During the operation of the cable, the local electric field stress concentration caused by factors such as internal impurities, semiconductor layer protrusions, and space charge accumulation under the action of voltage will generate partial discharge, which will affect the safe operation of the cable. Therefore, by detecting the partial discharge of the cable insulation, the aging condition of the cable insulation can be effectively judged, which is of great significance for the long-term stable oper...

AI Technical Summary

Problems solved by technology

The portable device for detecting cable discharge introduced in Chinese Patent Publication No. 1046045 adopts probe coupling technology, which requires manual movement of the probe during the detection process, making it difficult to detect deeply buried cables and cable operating places where personnel cannot enter

The existing partial discharge monitoring devices for power equipment have few analysis parameters, and often only analyze some basic partial discharge parameters such as discharge volume, discharge times, and the relationship between them and the discharge phase, and have no analysis related to the insulation aging of power equipment. Skewness and kurtosis of highly sensitive partial discharges

Moreover, the functions of the existing discharge monitoring devices are relatively simple, the ability to manage a large amount of monitoring data is poor, and the level of automation is not high, so it is difficult to meet the requirements of the power sector with an increasing level of automation

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