Bridge Solid State Circuit Breaker Based On DSP Control

The number of sensitive load facilities is increasing very fast with the development of power system, which makes more requirements on electrical power quality and stability of power system. How to break out the fault current within a short time to suppress voltage sag and enhance stability of power system becomes very important. Currently, the traditional mechanical circuit breakers are adopted in transmission line, but they have some disadvantages such as low switching speed, electric arc and short operation life, etc. Thus, a new breaker with current constraint and fast break-out of fault current is an urgent need of modern power system.The solid state circuit breakers (SSCB) have the advantages such as high switching speed, no electric arc and long operation. The SSCB can be divided into several kinds, such as SSCB based on SCR, SSCB based on GTO et al. But those SSCBs all have the disadvantages more all less. Via compared the two topologies of SSCB (the anti-parallel and the bridge), a new bridge SSCB based on IGBT was proposed as well as a control system. This control system adopts digital signal processor (DSP) and micro controller unity (MCU) as the CPU. The DSP is applied to data acquisition and processing, and MCU is adopted for HMI.The experiment and result show that the SSCB can break out fault current within 1ms. When the SSCB is used as a Transfer-switch, it would provide reliable protection for sensitive load facilities. It also can function well on current constraint with current limiter inductance. All these characteristics indicate its' application prospects in FACTS.