Parameter Selection and Prototype Development of UHV AC Switch Type Controllable Arrester

Abstract

This paper puts forward a flexible method to depress switching overvoltagein view of urgent need of UHV AC transmission system to deeply depressswitching overvoltage and shortcomingson reliability and economy of current methods including circuit breakers with closing resistors and conventional arresters. Core of the method is to install a controllable metal oxide arrester (CMOA) on line side of substation and a conventional metal oxide arrester in middle part of the line. The methodcan deeply depressswitching overvoltage and cancel the closing resistor of the circuit breaker. CMOA technology is the core of the flexible method to depress switching overvoltage. At present, CMOA mainly focuses on research of UHVAC switch type controllable metal oxide arrester (ST-CMOA). This paper expounded working principle of CMOA technology. Parameters of UHV AC CMOA were chosen, including rated voltage, controllable ratio, arrester body parameters and controllableunit parameters, etc. The controllable unit included controllable switch and controller. Then, the arrester body, the controllable switch and the controller were developed. On this basis, after integration, a UHV AC CMOA prototype with controllable ratio 15% was developed. Electrical performance tests of the prototype werecarried out. Feasibility and reliability of the switch type CMOAwere fully verified. Success of the CMOA provides a new technology for depressingswitching overvoltage on UHV AC transmission system. It can significantly improve economy and reliability of UHV AC project.