A Novel Hybrid Current-Limiting Circuit Breaker for Medium Voltage: Principle and Test Results

Although many attempts have been made to design a fault current-limiting circuit breaker (FCLCB) for medium voltage electric power systems, no economically attractive solution has been achieved so far. A novel concept for an F CLCB is introduced based on a hybrid arrangement of semiconductors, temperature-dependent resistors, and a newly developed fast-opening mechanical switch. The latter utilizes one part of an electrodynamic repulsion drive, which is concurrent with the moving double contact system. Laboratory tests as well as computer simulations of the complete FCLCB verify as an example the feasibility for the goal ratings 12 kV and 2/20 kA (single phase). A cost analysis shows the FCLCB to be more expensive than a conventional generator circuit breaker but to be in the price range of the Is-limiter and below the costs of superconducting FCL principles. It is concluded that the method provides the basis for further commercial product development.