High accuracy current transformer with small turn is an important sensor to measure leaking current of high voltage electric equipments.A single-turn cored structure current transformer with 500 turns secondary coil is designed.By using the principle of zero flux compensation to improve the ratio displacement and phase characteristics

the errors are restricted within the limits we need and the precision is up to 0.2 %.Experiments respectively on ordinary and high accuracy zero flux current transformers prove that the method has perfect compensation effect.