An AC Current Limiting and Interrupting Device for Low Voltage Systems

Document Type : Original Article

Authors

1 Electrical Department, Faculty of Engineering, Helwan University, Helwan, Egypt

2 Electrical Department, Faculty of Industrial Education, Suez University, Suez, Egypt.

Abstract

This paper describes the development of the hybrid fault current limiter and interrupting device (HCLID) which can be used successfully as a fast short-circuit protection means for low voltage AC industrial installations. The main components of the HCLID are a solid state commutation circuit that can supply a counter current injection from a stand-by pre-charged capacitor, saturable core reactor as the limiting impedance and fast mechanical contact switch all connected in parallel. Through this study, we can present a significantly improved and simplified approach that replaces the half-controllable silicon-controlled rectifier (SCR) in the commutation circuit with self-turn-off device such as integrated gate-commutated thyristor (IGCT). The use of high-performance semiconductors (IGCTs) as the commutating affords reduced recovery voltage, reduced losses, improved reliability and dynamic performance, and fast switching time (in μs). The new approach involves a fault detection using rate of current rise rather than the current magnitude and a time delay operating characteristic based on Piecewise Linear Electrical Circuit Simulation (PLECS) program. The control method is very simple. Simulations carried out during the research. Simulation results proved the practicability and validity of the new HCLID.

Keywords