Fuzzy logic application to out-of-step protection of generators

Efficient protection scheme against out-of-step (OS) conditions based on fuzzy logic (FL) technique is presented. The protection proposed makes use of an adaptive-network-based fuzzy inference system (ANFIS). The FL-based OS protection scheme developed has been thoroughly optimized and tested with ATP-generated case signals. The scheme designed displays almost perfect efficiency and high speed of OS detection. With the scheme designed the OS cases are identified much earlier comparing to standard impedance-based protection schemes. Wide robustness features of the ANFIS-based scheme have also been achieved.