Research on relay protection enhancement technology of distribution network based on LVRT
In recent years,the application of distributed photovoltaic systems with Low Voltage Ride-Through(LVRT)technology in power distribution systems has been increasing.However,the low contribution of short-circuit current in distributed photovoltaic sys-tems,it is different from the short-circuit characteristics of the traditional synchronous motor,which makes the traditional overcurrent protection system prone to mis operation.Aiming at this,an adaptive tuning strategy was proposed to improve the performance of the overcurrent protection system.This strategy is based on the working principle of LVRT.By estimating the fault voltage and using the voltage drop effect during the fault to compensate for the slight increase in current caused by the current limit control of the distributed photovoltaic inverter,the action speed of the protection system is accelerated,and the proposed method is verified by using DIgSILENT software on IEEE-12 node power distribution system.Experimental results show that while maintaining selectivity,the adaptive tuning strategy proposed in this paper significantly improves the action time limit of the protection system,verifying its effectiveness.
active distribution networklow voltage ride throughdistributed photovoltaicdistribution network protectionovercurrent pro-tection
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