ISOLATED POWER SYSTEM, AND PROTECTION EQUIPMENT AND METHOD FOR ISOLATED POWER SYSTEM

摘要

PURPOSE:To enhance an isolated power system with higher orientation accuracy and orientation probability for accidents occurred in systems and also to upgrade the power transmission line protection by a protection equipment and a protection method for the isolated power system. CONSTITUTION:When a ground fault accident of a system is detected by a ground fault detecting circuit 6, a grounding device 5 containing a grounding resistor 13 is connected to a cable way 14 and the ground by the detection output from the ground fault detecting circuit 6 during a predetermined time period from the time of occurrence of the ground fault accident. Within this time period, a fault point orientation processing circuit 8 takes in the detected outputs from a potential transformer 3 and a current transformer 2; based on the detection outputs, the orientation distance from the terminal A at a substation to an accident point F in the cable way 14 is computed, and a breaker 16 provided at the cable way 14 is opened by a power transmission line protection circuit 9. Thereafter, the grounding resistor 13 of the grounding device 5 is cut off from the cable way 14 by the output signal of the ground fault detecting circuit 6 to have an non-connection state between the cable way 14 and the ground.