Fault features of centrally integrated wind farms

With the increasing development of wind power, the capacity of wind farms is larger and its impact on grid operation has become more prominent. The fault current that wind farms provide is much different from the traditional synchronous machines. Wind farms in China are mostly centrally connected to power system. The central integration enlarges the impacts on power system. The correct action of the protection system is greatly affected. This paper analyzes the phenomenon that the wind farm side protection relay detects almost entirely zero sequence current and not correctly acts in case of ground fault, taking the outgoing line´s fault of a real wind farm for example. Furthermore, a real wind farm model is established in PSCAD/EMTDC to reproduce this phenomenon and analyze its influencing factors.