Improved microprocessor based distribution feeder earth fault protection using pattern recognition

High impedance electrical faults usually occur when a high-voltage distribution line conductor is contacted by a high-impedance earthed object, such as a tree, or when a conductor breaks and falls on a poorly conducting earth surface. Such faults affect the quality of power supply and may present safety hazards. It is important to have a sensitive distribution feeder earth fault protection which is capable of detecting high-impedance faults accurately. The new relay proposed by the authors with the aid of modern technology and development in microprocessors, will be able to discriminate correctly between normal and high impedance fault conditions, due to its ability to continuously monitor system conditions. The authors briefly discuss high impedance faults, current and voltage patterns, arcing faults analysis and the microprocessor based distribution