Reducing the Impacts of Distributed Generation in Transmission & Distribution Networks Protection Using Fault Current Limiters

Abstract

Increase in power generation capacity of electric power systems has lead to increase in the fault current level. In some cases fault current levels are exceeding the interrupting capability of existing transmission and distribution substations circuit breakers. Since short-circuit currents contain extremely high energy and can damage electrical equipment, either requires the replacement of a large number of existing substation breakers with higher rating breakers or the development of some means to limit fault current. Different technologies have been employed to design Fault Current Limiters FCLs such as turn-off a solid state switch to using superconductors that respond with increasing resistance in event of fault current. A proper design of Modular Level Based Solid-State Fault Current Limiters is proposed in this paper, describes the functioning of FCL and the amount of impedance they are required to insert in series with transmission or distribution substation are discuses. This will allow near instantaneous breaking of bus ties in transmission and distribution substations to reduce the available short circuit current and allow existing circuit breakers to clear at lower fault current levels. Since FCL's are installed in each phase of the line, the fault is viewed in perspective of per phase. For the purposes of this study, we consider phase to ground fault& phase to phase fault scenarios.

Keywords

• distributed generation
• fcl