Efficient practical method for differential protection of power transformer in the presence of the fault current limiters

The algorithms of the present generation practical differential relays are based on two methods. first method is ratio harmonic content current, and second one length time interval between zero-crossing points called gap-detection method. However, these methods suffer from installation fault current limiters (FCLs) in power system transformer (CT) saturation phenomenon. This paper deals with a simple for to secure their performance. In suggested method, classifying algorithm used categorize input signal relay then best employed. By this decision, takes advantage harmonic-based methods, while avoiding drawbacks. To prove robustness test bench resistive solid-state limiter (SSFCL) implemented examined different situations. results validate consistency accuracy modified technique not only absence presence FCL but case CT saturation.