Optimum selection of inductor as a current limiter in AC power systems

Current limiting reactors, CLR, are introduced in power networks to limit short circuit levels. The inductance of the size of the current limiting reactor is based line capacity and inductance. This paper discusses statistical route to optimize design margin available. With a view to assign a statistical rating to the inductor, simulations have been conducted with 100 randomly selected switching instants and fault introduced at 10% of the line length. The switching instants have been distributed over half period (10ms) of a 50Hz AC cycle. Statistical mean and standard deviation are arrived based on these results and minimum and maximum short circuit current for one standard deviation are considered as optimal statistical ratings for the system, covering faults in this range. The PSCAD and MATLab based simulations are carried out to for this study which suggests practical and cost effective approach for selection of such Current Limiting Reactors (CLR).