A circuit safety design method in the secondary circuit of a nuclear power plant switch cabinet

Abstract

The invention relates to a security design method of a circuit in a secondary circuit of a nuclear power plant switch cabinet. According to the method, two independent zero-sequence current transformers are arranged in a feeder circuit of the secondary circuit of a security-level emergency switch cabinet; zero-sequence current participating in an over-current protection function is led from the first zero-sequence current transformer; and the zero-sequence current participating in a grounding line selection function is led from the second zero-sequence current transformer. According to the circuit design provided by the invention, a secondary side of each zero-sequence current transformer is in a short circuit on a non-security-level line selection screen when a comprehensive protection device achieves the security level function, and the condition that a non-security-level circuit influences a security-level circuit to execute the security function is avoided.

Description

technical field [0001] The invention belongs to the circuit design technology of a switch cabinet, and in particular relates to a circuit safety design method in a secondary circuit of a switch cabinet in a nuclear power plant. Background technique [0002] The electrical switchgear includes primary equipment and secondary equipment. The primary equipment is the main body of the power system. It is mainly used for direct production, transmission and distribution of electric energy. The secondary equipment controls, regulates, protects and detects the primary equipment. [0003] The design of all electrical circuits in nuclear power plants must be based on their safety importance. According to the classification principles of electrical systems and equipment, all equipment and components of electrical systems that participate in the protection of the public under accident conditions are defined as 1E safety level. In the event of a single failure that may affect a system's pe...

AI Technical Summary

Problems solved by technology

However, the safety levels of the two functions involved in the zero-sequence current are different. The function participating in the overcurrent protection belongs to the safety level, while the function participating in the line selection belongs to the non-safety level.

Here the safety level circuit and the non-safety level circuit cross at the feeder zero-sequence current transformer, and the safety level circuit may be affected by the non-safety level circuit

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