Transformer Life Assessment Based On Blind Number Theory

As one of the most important electrical equipment of power system，whetherpower transformer could operate safely, reliably and economically or not is veryimportant for power system, and the choice of replacement time also determineseconomic efficiency during all the life. Blindly replacing power transformer thatcan continue to run will bring unnecessary losses to power company, and beingcontinue to run power transformer whose state is relatively poor will be able to lendto serious accident. In order to avoid the above situation, it is very necessary toassess effectively power transformer life. Because of the transformer serving for along time and the running environment being complicated, factors that influence theassessment of transformer life have a variety of uncertainties coexistence orcross-existence. Due to this characteristic, introduce Blind Number Theory intotransformer life assessment and study power transformer life under multipleuncertainties.First of all, evaluate power transformer life from the perspective of healthcondition. According to basic structure of the transformer, select a number ofindicators of easily measured and having significant impact on transformercondition assessment and establish transformer condition assessment system. Dueto this characteristic of uncertainties coexistence or cross-existence, introduceBlind Number Theory into transformer life assessment, use blind number expressevaluation parameter uncertainties, put forward a new method for determining thehealth index and establish transformer remaining life evaluation model based oncomprehensive health index. The model not only can give health status of thetransformer and state level, but also give remaining life expectancy, remaininglifetime interval and corresponding credits, possibility of not more than a certainyear，provides a theoretical basis for transformer remaining life evaluation.Then, assess power transformers life from the perspective of economicoperation. According to the life cycle cost management theory, construct powertransformer life cycle cost model, analyze life cycle cost and supply revenuesuncertainties and establish transformer economic life assessment model based onBlind Number Theory. This model not only can get transformer economic lifeexpectancy, but also can get the credibility of different year replacement and theeconomic life interval under different confidence level, and provides the basis forrealizing maximum economic benefit of power transformer.Finally, a example from Hebei Electric Power Company validates that power transformer life assessment study method proposed by this paper is reasonable andeffective. Since this method takes into account multiple uncertainties, and has astrict theoretical basis, thus reflects a high practical value.