风电场110 kV单回送出线主动探测式三相重合闸方法

In the case of three-phase tripping after a fault on the 110 kV single outgoing line in wind farm, the electromagnetic energy of transmission line attenuates rapidly, which makes it difficult to identify the fault characteristics. Then wind farm is in an islanded mode when it loses the connection with AC systems. Due to the power transmission blockage, the voltage and frequency of islanded system become unstable rapidly, which leads to wind turbines cut off simultaneously. A method for identifying fault characteristics is proposed by injecting low current from the converter of wind generator into the outgoing line. In the case of cutting off wind turbines, the main breaker of a wind turbine and circuit breaker near a wind farm are closed firstly. The power electronic devices of the wind turbine converter at the network side are inserted on within a very short time, making its DC-side capacitance discharge to the AC line. The protection criterion using current integral characteristics is utilized to realize identification of fault characteristics. A three-phase adaptive auto-reclosing scheme for 110 kV single outgoing line of wind farm is then proposed. The effectiveness of the fault characteristic identification and the active detection based reclosing scheme are verified by PSCAD/EMTDC simulation.