ELECTROMECHANICAL RELAYS

ELECTROMECHANICAL RELAYS

The electromechanical relays are based on the comparison between operating torque/force and restraining torque/force. The VA burden of such relays is high.The characteristics of these relays have some limitations.Each relay can perform only one protective function. Such relays are used for simple and less costly protection purposes.For important and costly equipment and installation static relays are preferred.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,cost and probable abnormal conditions.Between generators and final load points,there are several electrical equipments and machines of various ratings. Each needs certain adequate protection.The protective relaying senses the abnormal conditions in a part of the power system and gives an alarm or isolates that part from the healthy system.The relays used in this project are compact, self-contained devices which related abnormalconditions relays distinguish normal and abnormal conditions.