Trend Analysis of Dissolved Gas in Oil for Transformer

Abstract

Transformer’s dissolved gas analysis(DGA) is a very important means of transformer condition maintenance. With the development of technology, more and more transformers have been installed with online DGA devices,but there is no standard to determine the abnormal gas generation rate of dissolved gas in on-line oil. In order to mine the information of transformer online monitoring data, this paper firstly classifies the changing trend of dissolved gas volume fraction in four kinds of oil after data filtering, which are respectively rising, fluctuating, stable and falling. Then on the quantity statistics found that smooth and growth trend is the main trend. Then counted the growth trend of generation rate of gas volume, using the weibull distribution function and the normal distribution function fitting after their generation rate distribution, the sub-point of distribution function is used as the basis to judge the abnormal gas generation rate. The results show that the threshold method determined by us is strict and has regional characteristics.