Adaptive fuzzy based method differential transformer protection

The paper represents the development of an adaptive multicriteria algorithm based on fuzzy approach for the decision making part of the differential transformer protection schemes. At first some effective phenomenon have been examined. Then off-line examination results have been implemented for adapting the relay parameters such as fuzzy functions, weighting factors and tripping threshold to relay conditions and transformer characteristics. Self-adjustment of relay parameters has improved the speed of operation, dependability and security of relay. Different tests have indicated satisfactory results and less than half a cycle for the mean of operating time.