Research on The Application of Wavepacket Decompostion Based Non-unit Protection On The EHV Lines With Shunt Reactors

The analysis in theory shows that the protection based on the energy ratio of a high frequency component to a low one can be applied on the EHV lines equipped with shunt reactors and its performance is hardly influenced by the number and locations of reactors. The protection has satisfactory performance to metallic short circuit faults, so it´s immune to the different fault earth resistances. If a relatively higher frequency component is selected to be the low frequency component, the protection will be more adaptive to different fault inception angles and different fault types. Wavelet packet technique is employed to determine the energy ratio. Simulations show that the conclusions drawn in this paper are correct.