A method for measuring partial discharge characteristics of converter transformer oil-paper insulation

Abstract

The invention relates to a method for measuring a converter transformer paper oil insulation partial discharge characteristic, and belongs to the technical field of insulation detection of high-voltage electrical equipment. The converter transformer paper oil insulation partial discharge phenomenon belongs to a random process, in the method, based on the relation between the discharge capacity and the time interval in the discharge phenomenon, a series of relational graphs are built, and statistic characteristic parameters of partial discharge are extracted from the rational graphs, wherein the parameters include a degree of skewness Sk (representing the deviation degree of a spectrogram distribution curve relative to normal distribution), a kurtosis Ku (representing the sharpness of the spectrogram distribution curve relative to normal distribution), a Weibull distribution parameter scale parameter alpha and a shape parameter beta. Twenty characteristic parameters obtained by the method are used as the criterion for judging the types and order of severity of the converter transformer paper oil insulation partial discharge, according to the criterion, operators make a rational state maintenance strategy for the converter transformer, and a reliable technical support is provided for manufacturing and operating of the converter transformers.

Description

technical field [0001] The invention relates to a method for measuring the partial discharge characteristics of the oil-paper insulation of a converter transformer, and belongs to the technical field of insulation detection of high-voltage electrical equipment. Background technique [0002] As the main insulation form of internal insulation, oil-paper insulation plays a pivotal role in my country's high-voltage power transmission projects. In the actual operation of power equipment, oil-paper insulation not only has to withstand stresses such as AC power frequency voltage, DC voltage, lightning impulse overvoltage, operation impulse overvoltage, and polarity reversal voltage, but also the composite form of these voltages. The quality of insulating materials determines the reliability of power devices and even power transmission systems. Partial discharge tests of converter transformers under AC, DC, and polarity reversal voltages are helpful for early detection of insulatio...

AI Technical Summary

Problems solved by technology

However, the current problems are: the AC partial discharge detection technology is relatively mature, and the DC partial discharge detection technology is seriously lacking, mainly in the following aspects:

[0003] (1) There is no DC partial discharge signal detection device with statistical function on the market at present;

[0004] (2) There is no ready-made equipment at home and abroad to analyze the statistical characteristics of DC partial discharge signals;

[0006] (4) If we only judge the type and severity of partial discharge by observing the time-varying law of DC partial pulses mentioned in the standard, we often need to rely on a lot of actual experience or perceptual knowledge, which is very important for judging the type and development of partial discharge. degree is very difficult

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