Title: STUDY OF IMPEDEANCE RELAY
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Title: |
STUDY OF IMPEDEANCE RELAY |
Author Name: |
Mr. Nilesh Pangare, Mr. R. S. Desai |
Abstract: |
Increase in line lengths, power transmitted introduced a number of new difficulties in relation to protection. New techniques become necessary to tackle this problem. Firstly important to see these lines are not unnecessarily disconnected, at the same time shorter operating times for protective relays are demanded on faulted section sections to preserve stability. Moreover, extreme variations of fault current are often encountered with long lines necessitating the protective relays to take this aspect. Two major types of transmission line protection been developed extensively to meet requirements are distance and carrier current systems. Pilot wire system of protection is not applicable to long and overhead transmission lines because of high cost of pilots and unreliability. Transmission line demo panel is designed to demonstrate fault clearing process on transmission line using distance (impedance) relay. The principle of operation of these relays depends on fault current and power factor under fault conditions. As a matter of fact such relays are designed to operate according to impedance of line up to fault point or ratio of voltage to current under fault condition. As fault impedance is proportional to distance of line from location of relay to fault point, relay indicates distance over which fault has occurred. |
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