Study On Degree Of Gray Incidence Of Power Transformer Insulation Of Fault Diagnose And Its Application Based On Dissolved Gases Analysis

The operation reliability of the power transformer,which is the major equipment in power system,directly related to the safety and stability of whole power system. In accordance with the technological difficulties encountered in the process of insulation supervision based on the Dissolved Gases Analysis (DGA),several kinds of model and method are presented to improve the reliability and precision of fault diagnosis of the power transformer. Main research content includes:Starting from the study of occurring and resolving theory for gases in transformer oil,the relationships between oil-dissolve gases and the transformer fault types are further analyzed,all of which contribute to the final conclusion that the contents and constituents of oil-dissolved gas can be considered as the character parameter for diagnosing transformer faults.By deeply studying the common transformer faults diagnosing methods,such as three-ratio methods and improved electrical committee agreements,several shortcomings such as uncertainness judgment when the fault reasons,phenomenon and principles come out together while can not consistent to each other etc. For this reason,the old methods can not fully meet need to engineering practical application.The enclosure structure of power transformer leads to difficulties in condition monitoring and fault diagnosis. However,if considering from another angle,the working power transformer,which is neither a white system with definite status information,nor a black system without any information about status information,can be defined as typical gray system.In this paper,the gray relationship theory is introduced into transformer insulation diagnosis. Based on analyzing the relationship between the reasons of transformer insulation faults and contents of each gases dissolved in transformer oil,the standard mode character parameters matrix is presented.The character of distinguishing coefficient is analyzed. For the purpose of overcoming the disadvantages of general gray relationship degree theory,a creative gray relationship degree calculation formula ground on spatial geometry theory. In addition,4 satisfaction axioms is proved,by which the relationship order can be confirmed. By this method,abundant information binding behind every relationship coefficient can be fully utilized,which will make up the limitation of Deng relationship degree to some extend. The mathematics and physics meaning is prominence.Developed by Visual Basic,A software package is built in the environment of windows98. Plenty of diagnosis examples demonstrate the validity of the gray relationship analysis method in diagnosing power system insulation faults. The transformer insulation condition can be analyzed,as well as the fault position can be located by recognizing the fault types. The diagnosing precision is much higher than former three-ratio method.