Oil Cooled Current Transformer High Voltage Transmission Systems: Measurement and Monitoring: Oil-cooled CTs are commonly used in high voltage transmission lines to measure current flow. They provide accurate current readings necessary for system monitoring, control, and protection. Protection: They are integrated into protective relaying schemes to detect abnormal current conditions like overcurrents or faults and to trigger protective devices like circuit breakers. Oil Cooled Current Transformer In Vadodara Oil Cooled Current Transformer In Gujarat Oil Cooled Current Transformer In India