| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protection relay system of a distribution system capable of surely and easily achieving protection coordination in the event of a power failure/power restoration and of having flexibility in a throwing order and selective interruption for loads. <P>SOLUTION: The mode switch setting function of a digital relay A enables selective interruption setting and throwing order setting by digital relays B to switch to a host computer C. The load current holding function of the digital relay A holds the load current immediately before power failure occurrence obtained from respective digital relays B, enabling to select loads thrown in a sequential order after starting an emergency generator due to the power failure occurrence. The load current value diagnosis function of each digital relay B identifies that rush current and load current are stabilized, thereby protecting a false protective operation when power is restored. When there is a load with an abnormal current value, the selective interruption/throwing order setting exception function of each digital relay B causes the digital relay A to except the load from the selective interruption setting and the throwing order setting. <P>COPYRIGHT: (C)2008,JPO&INPIT |
