High Frequency Impedance Based Fast Directional Pilot Protection Scheme for Distribution Network With Wind DGs

With the ever-increasing integration of wind power into the distribution network in the form of distributed generations (DGs), the fault direction judgment is an important question for such a network with multiple branches. Due to the phase-angle controlled characteristics of the fault current supplied by wind DGs, the optimal application environment for the traditional directional elements no longer exists. To deal with this issue, a high frequency impedance based fast directional pilot protection scheme is proposed in this paper. Firstly, the high frequency impedance model of a wind DG is established according to the time sequential characteristics of its response to faults. Secondly, the fault direction identification criteria are described based on the high frequency-domain fault additional network. On the one hand, the proposed scheme is not influenced by the different control strategies of the wind DGs. On the other hand, the proposed scheme does not rely on a strict synchronized communication system. The simulation results prove the feasibility of the proposed scheme.