A NEW DIGITAL PROTECTIVE RELAY BASED ON FUZZY LOGIC AND VALUE ESTIMATION

In this paper, design and application of a new digital protective relay based on fuzzy logic and value estimation to a radial power system protection was presented. A novel approach based on value estimation was investigated for the proposed fuzzy logic based protective relay. In addition to the theoretical aspect of fuzzy logic, mathematical definition .of value estimation, detection and measurement of faulty current, determination of its duration, decision mechanism and detailed system architecture were also introduced. The examined technique based on fuzzy logic and value estimation to control the protection action of the protective relay was intended to improve the performance of a conventional protective relay control for human safety and system reliability with the use of a fuzzy logic controller. The difference between estimated and sampled values was used to form the rule base. Proposed relay architecture was used as a detector and was developed to predict faults and to protect particular sections of a designed prototype radial power system at an early stage. Performance analysis was made, and related results and discussion were given.