Research on adaptive current instantaneous trip protection for active distribution network line with DFIGs

摘要

An analytical expression of the stator current of DFIG and the flux of stator and rotor is obtained, by analyzing the transient model of DFIG (Doubly-fed Induction Generator). And the analytical expression of the active power of DFIG and the rotor reaction flux is obtained by vector analysis of stator current and rotor flux. Then, this paper infers the analytical expression of the active power output and the stator short circuit current. Next, the instantaneous trip protection action value of the access point downstream must be adjusted in real time with the different output of the DFIG wind field is analyzed. Thus, this paper proposes the adaptive instantaneous trip protection scheme based on the action value to be adjusted in real time with the different output of the wind field. Referring to the parameters of the first exemplary project in which the dispersed wind power is integrated into the 10kV local power grid, the active distribution network simulation model is established in PSCAD/EMTDC, with numerous simulation tests carried out for line protection. Simulation results show that the proposed method can effectively solve the sensitivity and selectivity issues of the instantaneous trip protection action of the wind field access point downstream in the distribution network.