Development of a Real-Time Online Condition Monitoring System using Tan delta leakage current for Current Transformer Health Assessment

Current Transformers (CTs) are foundational components in high-voltage electrical systems, enabling accurate protection and metering. However, their long-term performance is vulnerable to insulation degradation caused by environmental aging, moisture ingress, or persistent electrical stress. While routine diagnostics such as annual Tan Delta testing, Thermovision scanning, and visual inspections provide periodic insights, they often fail to predict abrupt failures. When such failures occur unexpectedly, the consequences can be severe : they may damage adjacent equipment like Circuit Breakers and Isolators, trigger protective tripping, and result in large-scale outages with serious operational and financial implications.