| 摘要 |
PROBLEM TO BE SOLVED: To provide a network protector for preventing the break error of a protection circuit breaker due to an inrush load current. SOLUTION: A current phase angle detection relay 23 has characteristics for operating when the phase angle of current flowing into a load side is delayed by 0-π/2 to a network bus voltage Vn. A control circuit 24 opens a protector circuit breaker 15 when the current phase angle detection relay 23 does not operate and the operation state of the network relay 21 continues at least for a specific time. As a result, the control circuit 24 judges that the reverse power (current) detected by a network relay 21 is not the reverse power and prevents a circuit break signal from being outputted to the protector circuit breaker 15 even if the network relay 21 detects the inverse power (current) when the phase to the network bus voltage Vn in a load inrush current is in the fourth quadrant, thus preventing break error to the load inrush current.
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