Transformer Condition Assessment Based On Improved Grey Target Theory

As the voltage grade of power grid has been improving on, the transformer is becoming equipment which is very important and expensive in high-voltage transmitting system. However, if fault occurs on transformer, it will cost lots of time for repairing and have a serious influence results. Completed state assessing system must be established to keep the transformer running stable and long.This paper assesses its state accurately by dynamic grey target, which endows each index with different weight based on their degree of importance, after deeply studying the traditional grey target. Meanwhile, the transformer top oil temperature and the load data are adopted as state variables in the dynamic grey target theory to consider the advantages of the collected data comprehensively, which uses load data and temperature as the variables of transformer state to obtain the model and approaching degree,which can be used to assesses the transformer's health status by pre-defined strategies. The result of analyzing a transformer shows that it can make assessment results more accurately by considering the transformer top oil temperature and the load data.In addition, this article carefully studied of the state assessment method in CBRM, combined the dynamic gray target theory with the evaluation method, made the parameters which impact the health index of transformer as state variables, and calculated the approaching degree. By using the range mapping, we obtain the transformer current health index, and then calculate other transformer indexes. Example shows that the proposed method in this paper can correctly obtain the health status of the transformer, and is effective.