Research Of New Protection Of Transformer Based On The Equivalent Instantaneous Inductance Of Energizing Circuit

How to discriminate between internal fault and magnetizing inrush current is thedifficulty of transformer protection when applying differential relay. The exiting criterions to discriminate between internal fault and magnetizinginrush current were analyzed and the conclusion is: the performance of correlationalgorithm is superior to the others in criterions based on wave-form. Based on theprevious research. A new scheme named "new method to discriminate betweeninternal fault and magnetizing inrush based on characteristic of equivalentinstantaneous inductance in time region" is put forward, and its efficiency is provedby simulation of EMTP and TEQSIM. The paper brings forward a new transformerdifferential protective scheme based on the sample data, and it can act very fast andreliably. In order to analyse and validate the protection,The hardware of relay devicewhich can test new relay theory is developed based on the C language. At the sametime, we developed a facility test system that can simulate the working states oftransformer, and the test system is proved very convient and efficient to testtransformer protection.