Study Of The Diagnosis Method For The Power Transformer Condition

As the ultimate element in the power system, power transformer’s operation statement is directly related to the security and stability of power system. Condition based maintenance compared with time based maintenance, as a maintenance mode which can save maintenance cost, shorten outage time, extend equipment life span, has become a focus of research. Correct understanding of the power transformer’s operation statement is the key to the success of condition-based maintenance. In order to learn more about operation statement about transformer, its status needs be analyzed and diagnosed.Firstly, from test of dissolved gases, electrical test and test of transformer oil, this paper analyzes status information of the transformer and establishes a scientific and objective system of status information. Secondly, this paper formulates a marking scheme of status information, divides the health of the transformer into5levels and establishes a hierarchical evaluation model for winding, bushing, core and insulating oil. Finally, on the basis of the data which reflects the operation statement of the transformer, it establishes a correspondence between the status information and the fault causes. According to this correspondence, this paper establishes a diagnostic model of the transformer based on fuzzy theory. The diagnostic model constructs the membership function of each component. On the basis of the relative importance of status information, it selects the AHP model to determine the subjective weight of status information and selects entropy to determine the dynamic weight.The given example shows that the established model can distinguish power transformer’s operation statement and analyze the possible and occurred faults. The diagnostic conclusion helps to establish maintenance scheme of transformers and gives the economic foundation for implementing condition based maintenance of power transformers.