Analysis On Current Compensation Methods And Research On Scheme For Block Of Inrush Current In Transformer Differential Protection

With the development of electric power system,high capacity and super voltage transformer is used more commonly.The status of transformer become more important in electric power system,and the requirements to differential protection performance of transformer are becoming higher.First,This paper analyzes and compares three current compensation methods used in wye-delta connected transformer differential protections. Impacts of these current compensation methods to identify inrush currents which emerged from single-phase,two phases or three phases when a transformer is energized without a load were studied.And a new configuration of current transformer(CT) in transformer differential protection to improve the ability of identifying inrush currents is proposed.And then the fuzzy recognition is introduced and comprehensivly using these three current compensation methods is proposed.Based on this,the scheme for secondary harmonic block of magnetizing inrush current in transformers based on fuzzy logic is proposed,this algorithm has great progress both in the operational speed and anti-misoperation.