Abstract:When the small hydropower stations are linked with the power system, it becomes difficult to judge the type of the fault which causes the running of the hydropower station unsteadily. If the fault takes place in the distribution line which links to the hydropower stations, the reclosing always fails. In order to solve this problem, adopt nonvoltage to reclose and improve the traditional reclosing control logic. A new reclosing relay device based on programmable logic controller is designed to resolve the problem of the compatibility with the other relaying actions and to improve the success rate of reclosing. The simulation running of the device in Guangdong Province proves its effectiveness, the time setting and control strategy of the reclosing device has a certain significance for engineering applications.