| 摘要 |
A digital relay according to the present invention includes: a voltage detection unit which is imbedded in the digital relay and is connected to both ends of a secondary coil of the current transformer in order to detect whether or not a secondary circuit of the current transformer is opened; a secondary circuit voltage detection circuit unit which is connected to the secondary coil of the current transformer in parallel and includes a relay for applying a bypassing electric current whose circuit is closed by an excitation control signal; and a control unit which is imbedded in the digital relay and connected to the voltage detection circuit of the secondary circuit to determine whether or not the secondary circuit is opened by comparing the voltage of the both ends of the secondary coil with a set reference voltage value and outputs the excitation control signal of a corresponding phase determined to be opened to the relay for applying the bypassing current connected to the current transformer in parallel in order to operate to a closed circuit location. |
