A High Precision Multi-Ratio Three-Stage Current Transformer (CT) for Loss Measurements of Extra High Voltage (EHV) Three-Phase Shunt Reactors with Test Voltages up to 1100 kV

An overview of the development and performance of special high precision multi-ratio three-stage CT and its application for loss measurement of EHV three-phase shunt reactors With AC test voltages up to 1100 kV at Royal SMIT Transformers are presented and discuss. It features current ratios of 500A/1A, 400A/1A, 300A/1A, 200A/1A, and 100A/1A with ratio errors within $3\times 10^{-6}$ in both magnitude and phase with burdens up to $1.0\ \Omega$ and at power frequencies of 50 Hz – 60 Hz.