Study On The New Principle Of Main Protection Of Transformer Based On The Usage Of Voltage

Based on the existing theories of transformer protection, the voltage is introduced in this paper. Furthermore we put forward the conception of instantaneous power and instantaneous excitation inductance. After that the new theories that are used to discriminate the inrushing and faults are advanced here. They are power difference theory, the ratio of reactive power and active power theory, instantaneous power frequency analysis theory and instantaneous excitation inductance characteristic theory. The phenomenon of over_saturation has no influence to instantaneous power theory. And the instantaneous excitation inductance theory can describe the function state of transformer in nature. In the end it is proved that the new theories are correct by a mass of test such as EMTP simulation and mixed simulation. This paper is supported by "Nation Natural Science Fund— Study on New Principle of Transformer Protection Based on the Nonlinear Behavior of Energizing Circuit", The serial number is 50277012 。...