Syed Basit Ali Bukhari

Protection Coordination Using Superconducting Fault Current Limiters in Microgrids

Power generating units in the form of distributed generation (DG) are integrating with microgrid (MG) systems to supply reliable power to users. The trend of an integrated power supply is increasing continually to meet growing energy demands. Besides certain advantages of the MG system, some interconnection and system protection issues pose a challenge in terms of implementation. These problems need to be addressed in order to facilitate smooth operation of power systems. Superconducting fault current limiters (SFCLs) provide the best performance and unique protection features to electrical power systems during various fault conditions. This paper describes modeling, characterization, and implementation of SFCL in an MG system to enhance protection coordination. The proposed SFCL is modeled in MATLAB/ Simulink software and the performance of the system is validated through simulation results. It is also shown that the proposed SFCL provides a means of better relay coordination during various fault conditions. This is achieved by incorporating well-calculated design parameters of SFCL and its placement at optimal locations.

Short-Circuit Fault Protection of a Low Voltage DC Distribution System using Superimposed Current Components

Low voltage DC (LVDC) distribution systems are gaining attention as customer loads are shifting towards power electronics-based equipment. The DC distribution system has the advantage of supplying power to these power electronic-based loads with high efficiency and without undergoing an energy conversion process. However, the power electronic components used in the LVDC distribution system are vulnerable during short-circuit faults. These components must be protected during the short-circuit faults for a safe and reliable operation. Therefore, this paper proposes a protection technique based on DC short-circuit fault current behavior. The fault is detected via a superposition principle. A fault current limiter (FCL) is used to suppress DC fault strength and reduce the stress from the circuit breaker. Finally, a solid state circuit breaker (SSCB) is used to isolate the fault point. The simulation results show that the proposed protection Scheme operates quickly enough as per expectations to avoid damage to sensitive power electronic devices.