Surge analysis of onshore wind farm due to multiple lightning strokes

摘要

China had built the largest wind power capacity in the world, and it is crucial to assess and control the lightning surge and surge arresters failure risk in wind farm to fulfill the safe and stable operation of power system. A typical wind farm model is established in EMTP. The lightning surge, failure risk of surge arresters and mean time between failure (MTBF) of the wind farm main equipments due to first, subsequent and multiple strokes are analyzed. The influence of peak current distribution and current waveform of lightning stroke, grounding resistance and grounding pattern of wind turbines on insulation coordination of wind farm and failure risk of surge arresters are also investigated. The results show that ground potential rise, absorbed energy of HV surge arresters and the surge amplitude at boost transformer HV side of stroked turbine is most serious than other turbines under all condition. The MTBF of boost transformer and high voltage side surge arresters due to first and subsequent stroke greatly influenced by lightning stroke peak current distribution, horizontal grounding conductors (HGC) connected between every two turbine tower groundings and wind turbine grounding resistance.