Apparatus and method for controlling circuit breaker for static synchronous compensator
Provided is an apparatus and method for controlling a circuit breaker for a static synchronous compensator (STATCOM) such that the circuit breaker installed in a branch line for the STATCOM is operated according to the current control characteristics of the STATCOM, the apparatus including: a transformer protector for detecting the differential current between primary current and secondary current of a transformer connected in series to the circuit breaker in the branch line, and controlling the opening/closing of the circuit breaker; and a STATCOM controller for controlling an operation of the STATCOM, wherein the STATCOM controller outputs, to the transformer protector, an opening suspension signal for suspending the opening of the circuit breaker when overvoltage occurring in the STATCOM is detected, and the transformer protector suspends output of a circuit breaker opening signal to the circuit breaker according to the received opening suspension signal.
1. An apparatus for controlling a circuit breaker for a static synchronous compensator (STATCOM) installed in a STATCOM-dedicated branch line branched from a main bus of a power system, the apparatus comprising:
a transformer protector for detecting a differential current between primary current and secondary current of a transformer connected in series to the circuit breaker in the branch line, and controlling opening/closing of the circuit breaker; and
a STATCOM controller for controlling an operation of the STATCOM, wherein the STATCOM controller is configured to output, to the transformer protector, an opening suspension signal for suspending the opening of the circuit breaker when overvoltage occurring in the STATCOM is detected, and the transformer protector is configured to suspend output of a circuit breaker opening signal to the circuit breaker according to the received opening suspension signal,
wherein the transformer protector is configured to determine whether or not a fault occurs in the power system from the detected differential current and output the circuit breaker opening signal to the circuit breaker when the fault occurs in the power system, and
wherein the transformer protector is configured to output the circuit breaker opening signal to the circuit breaker regardless of whether or not the opening suspension signal is received from the STATCOM controller when the fault occurs in the power system.
2. The apparatus according to claim 1 , wherein the transformer protector is configured to suspend the output of the circuit breaker opening signal to the circuit breaker even in an operation interval of a predefined curve for operating characteristic when the opening suspension signal is received from the STATCOM controller.
3. A method of controlling a circuit breaker for a STATCOM installed in a STATCOM-dedicated branch line branched from a main bus of a power system, the method comprising:
detecting, by a STATCOM controller, overvoltage occurring in the STATCOM;
outputting, by the STATCOM controller, an opening suspension signal for suspending opening of the circuit breaker to a transformer protector when the overvoltage is detected; and
suspending, by the transformer protector, output of a circuit breaker opening signal to the circuit breaker according to the received opening suspension signal;
detecting, by the transformer protector, a differential current between primary current and secondary current of a transformer connected in series to the circuit breaker in the branch line;
determining, by the transformer protector, whether or not a fault occurs in the power system from the detected differential current;
outputting, by the transformer protector, the circuit breaker opening signal to the circuit breaker when the fault occurs in the power system regardless of whether or not the opening suspension signal is received from the STATCOM controller; and
opening, by the circuit breaker, the branch line according to the received opening signal.
4. The method according to claim 3 , wherein the suspending of the output of the circuit breaker opening signal to the circuit breaker is performed even in an operation interval of a predefined curve for operating characteristic when the opening suspension signal is received from the STATCOM controller.