DESIGN & DEVELOPMENT OF MICROPROCESSOR/PC BASED UNIVERSAL 0/C RELAY

Abstract

Protective relaying is necessary with almost every electrical plant and no part of the power system is left unprotected. The choice of protection depends upon several aspects such as type and rating of the protected equipment, its importance, location, probable abnormal conditions, -cost etc. between generator and the final load point there are several equipment and machines of various ratings. ' Each needs adequate protection. There are two requirements for protective relaying (a) minimum damage to equipment and (b) Minimum interference with production due to loss of power during short circuits. With fast expansion of interconnected power system the protective relaying had assumed great significance. The conventional electromechanical relay has been replaced by solid state relays because of better performance, low burden on CT, compactness of the unit and reduction in panel space, less maintenance, non over - reaching tendencies and greater accuracy of characteristics. Inspite of these benefits the analogue system have number of disadvantages like temperature variation, noise & presence o1 various non linearitie .