Short Circuit Fault Location in DC Power Network Using Intelligent SiC Solid-State Circuit Breaker

The purpose of this paper is to introduce a digital-controlled, SiC MOSFET based, self-powered, autonomously operated 380V/20A solid state circuit breaker (SSCB) that offers the capability to identify the location of a short circuit fault in addition to the basic fault current interruption function. The SSCB is based on the concept of operating a buck converter using tri-mode control strategy: ON, OFF, and PWM Current Limiting (PWM-CL). The SSCB can conduct current in ON state, while interrupt current in OFF state. The SSCB will enter the PWM-CL state before switch to OFF state when there is a short circuit fault. In PWM-CL state, we propose an algorithm that first extracts the inductance between the SSCB and the fault location by injecting voltage pulses into the DC power network and measuring its response, and then calculates the distance using the known per-unit inductance value of the power line. The paper has proposed a method to choose the frequency of voltage pulses. The paper analyzes the inductance calculation error for different fault locations and shorting resistances. The concept is verified by simulation and experiment using a new SSCB prototype.