Fault Diagnosis Model Of Power Transformer Based On Grey Relation Using Combined Weights

Power transformer is the key apparatus at the transformer substation,the safety of its operation and reliability relate to the safety and stabilization of power system directly.It is important to analysis the power transformer diagnosis.Dissolved Gas Analysis (DGA) which is one of the most useful means to analyze the oil-filled power transformers can be carried out under the condition of on line operation.In recent years,many of the intelligent diagnosis methods in the field of transformer diagnosis have a very broad application.Such as neural network,expert system fuzzy theory, gray theory,rough set theory etc.In this paper,according to the relationship between the components of different gases dissolved in the oil of transformer and the fault types of power transformer.Propose the typical fault reference vectors.Through the gray relation theory,established the Grey Relational Model between the components of different gases dissolved in the diagnosed transformer and the typical fault vectors of power transformer.According to the correlation size,determine the extent of belonging to a certain fault type.When determine the transformer’s fault types,the weights of the dissolved gases are different.In the paper,the experts using AHP determine the subjective weight of every dissolved gas when diagnose the transformer fault types.But,there are too many subjective factors in determining the weight of every indicator by using AHP.In this paper,the experts using AHP determine the weight of every indicator. Then,the grey relational analysis is introduced in order to avoid non-uniform weight distribution errors caused by experts.The objective weight of every indicator is obtained by applying entropy method.The combined weights of indicators are comprehensively determined by AHP and entropy weight method.This enhances the evaluation processes.Through some examples,this diagnostic method is analyzed and discussed.it’s diagnostic result is the same as that by hanging core test,and when the Three-ratio method is missing code,it’s still effective.At the same time,can determine a single or multiple fault types.It shows that the fault diagnosis model of power transformer based on grey relation using combined weights is effective.