阐述了“三取二”保护逻辑的基本原理和特点, 通过对5种保护逻辑建立数学模型, 从可靠性的角度分析了保护逻辑的误动率、拒动率和可靠性, 论证了“三取二”保护逻辑既能防止误动又能防止拒动, 具有较高的可靠性和优越性。结合上海奉贤站的实际, 以阀短路保护为例, 剖析了在不同动作策略下的“三取二”保护逻辑模块所处的位置以及出口方式, 证实了无论从可靠性的角度分析, 还是从经济性的角度考虑, 向家坝—上海±800kV特高压直流保护系统采用“三取二”保护逻辑是科学的, 确保了特高压换流站的安全稳定运行以及隐患排查工作。

This paper elaborate that “two out of three” basic principles and characteristics of the protection logic, protection logic malfunction rate by a mathematical model of the five kinds of protection logic, from the reliability point of view, refused to moving rate and reliability “ two out of three ”protection logic can prevent malfunction and prevent tripping, high reliability and superiority. Combined with the Shanghai Fengxian station actual valve short circuit protection, for example, analyze the different action strategies under the “two out of three” to protect the position of the logic module and export,confirmed by the analysis from the point of view of reliability, or from the the point of view of the economy Xiangjiaba-Shanghai ± 800 kV UHVDC protection system using the “two out of three” protection logic of science, to ensure the safe and stable operation, and the hidden danger of UHV converter Station.