| The3~10kV medium voltage switchgear, which contains high-voltage current-limiting fuses and vacuum contactor, has the advantage of high reliability, low cost,reasonable protection and frequent operation. It is widely used in high-voltage unitauxiliary system of power plant, as switchgear of3~10kV motor and transformer.The selection method of high voltage fuse and vacuum contactor circuit(F-Ccircuit) is complicated. After comprehending the characteristic and protectivetheory of high-voltage fuse and vacuum contactor, it was put forward in this paperthe method to choose high-voltage fuse or vacuum contactor and the method tocooperate between contactor’s short circuit withstand capability and high-voltagefuse’s current characteristics.Through the cooperation of high-voltage fuse and vacuum contactor, the F-Ccircuit was achieved protection function of3~10kV unit auxiliary system load.Paper have study how to realize protection with fuses and protection relay setting ofvacuum contactor, and some examples were given.Based on the cooperation between fuse and vacuum contactor, the maximumload capacity of F-C circuit was solved, and the way to choose other equipment andconductor of F-C circuit was showed in this paper. The research also highlightedthe method to choose power supply cable of long-term overload circuit.Compared with the conventional vacuum breaker program, the advantage ofeconomic benefits of F-C circuit was given. The scopes of F-C circuit were alsopresented. |
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