A High-Precision Current Transformer for Loss Measurements of EHV Shunt Reactors

An overview of the development and performance of a special high precision multi-ratio three-stage CT and its application for loss measurements of EHV three-phase shunt reactors with test voltages up to a phase voltage of 1100 kV at Royal SMIT Transformers are presented and discussed. It features current ratios of 500 A/1 A, 400 A/1 A, 300 A/1 A, 200 A/1 A, and 100 A/1 A 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 50–60 Hz.