To Study the Design of Current Transformer and make the Improvement in Existing CT used in Air Circuit Breaker

Abstract

Circuit Breaker is a switching device, capable of making, carrying and breaking current under normal circuit conditions, carrying fault current for a specified time and breaking currents under specified abnormal system conditions such as short circuit faults, ground faults etc. In Air Circuit Breaker, arc-quenching medium is air at atmospheric pressure. Current Transformer (CT) is an integral part of air circuit breaker. It is use for measurement and protection purpose in Air Circuit Breakers. The output of the CT will be the input for Electronic Release. Electronic release is the heart of protection circuit. Based on the signal received from CT, Electronic release will give signal to Flux Shifting Device to Trip the breaker under faulty conditions. Under routine operation, the Electronic release displays the Current, Voltage, Power and other parameters of the system based on the inputs from CTs. Present competitive market requires robust and accurate current monitoring and related functions. To cater this market requirement, the Current Transformer de- sign needs to be reliable and satisfying the required customer demands. A need was felt for improvement in reliability and robustness of existing design of Current Transformer for Market requirement. The existing CT design needs to be studied, analyzed and based on the requirement, new CT design needs to be developed. Prototype CT samples of new design to be tested validated for required performance. Post satisfactory validation of the new design of CT, it will be replacing the existing design.