Investigation on Protection Schemes of an Existing Wind Farm in India

Green power generation/smart power generation using wind power is gaining popularity across the globe. However, wind power being irregular and sporadic in nature, poses several challenges for grid integration like security, stability and protection issues. Regulatory authorities are constantly tightening the regulations for grid integration of wind power. Comprehensive protection schemes and ensuring generator connectivity to the grid under fault conditions is necessary to advance the transient steadiness of the system and avoid blackouts. Proper forecasting and scheduling can largely address these issues. In this paper, an existing wind farm is modelled in Electrical Transient and Analysis Program (ETAP) software for an in-depth study using real-time wind farm data for simulations. IEC 60909 standard is followed for load flow calculations and short circuit analysis. Existing protection schemes are evaluated, and relay coordination is undertaken for both Type-1 and Type-4 Wind Turbine Generators (WTGs). Relay coordination is done using inverse time-current curve relays for 33 kV feeders, power transformer LV side and 110 kV grid side. Also, a suitable relay setting is incorporated for optimal relay coordination and to maintain proper sequence of operation.