A New Method of Fault Direction Identification for Different Types of Renewable Energy Source Integrations

The characteristics of the short circuit current of renewable energy sources are quite different from those of traditional generators. When applied to tie lines and collector lines of renewable energy sources, the traditional directional elements may not operate correctly. A new method of fault direction identification suitable for inverter power sources and doubly fed power sources based on the fault features of renewable energy sources is proposed. The fault type is judged by sequence voltage. The fault direction is identified by comparing the amplitude between the sequence currents and the phase angle between the sequence voltage and the sequence current, without distinguishing whether the crowbar of the DFIG is triggered. The results of digital simulations and experiments show that this method is not affected by the types of renewable energy sources connected to the power grid and can correctly judge the fault direction in different fault types, which has good engineering application value.