A Coordinated Protection Strategy for Wind Integration

High penetration of renewable energy sources (RESs) in power grid may introduce more fault scenarios due to the RES characteristics of uncertainty and variability. Based on relay protection and the coordination of relays, this paper developed a relay-based protection strategy to protect a wind turbine generation (WTG) system from short circuit scenarios. The strategy has two hierarchical level protection (zone-level and system-level) and three zones of primary protection (transformer, bus, and feeder zone). For the zone-level, the assigned relays and circuit breakers (CBs) protect each zone from the faults. For the system-level, the relays coordinate with each other to isolate faults based on their location and follow a defined coordination interval between CB trips. A novel testbed with the Hardware-in-the-loop (HIL) simulation is also developed to test the protection strategy in one system of POWER Engineers, Inc. Relay low-level interface was utilized with HIL simulation to minimize the error from the simulation. Simulation results demonstrated that the algorithm met the testing specifications.