| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a limiter in which the circuit-breaking set value of the circuit-breaking action at the time of electricity sales can be established arbitrarily and an unnecessary circuit-breaking operations can be prevented. <P>SOLUTION: The limiter 1 is provided with an electrical path 3, contacts 4 installed in the electrical path 3, a tripping circuit 5 for tripping the contacts 4, and a current detection part 6 to trip the contacts 4. The current detection part 6 has a CT 61 for detecting the current of a voltage phase 31, a power supply circuit 62, a current detection circuit 63, a voltage detection circuit 64, and a decision processing part 65 for outputting a tripping signal. The decision processing part 65 decides the direction of power flow based on a vector sum of current and voltage; and when the vector sum of current exceeds the circuit-breaking set value specified, according to the power flow direction and the excess state time becomes longer than that of the delay-time characteristics, outputs a tripping signal. Thereby, since the circuit-breaking set value can be established arbitrarily, according to the power flow direction of power purchase direction and the power selling direction, the circuit can be prevented from unnecessarily breaking at the time of power sales. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
