The capacitive leakage current of high voltage current transformer at rated voltage has some effect on the error of the instrument transformer.For measuring the capacitive leakage error accurately

the mechanism of capacitive leakage current generation and the model of its influence on the error of the current transformer are obtained by theoretical derivation.A kind of improved method which can measureμA class leakage current amplitude and phase

also known as reference phase lock method

is proposed.The pros and cons of applying voltage and current method and the reference phase lock method are analyzed.The capacitive leakage error test of a set of high voltage current transformer is measured by the proposed method.The agreement between the theory and the test method is verified by way of testing and comparison of applying voltage and current methods at various conditions.The reference lock phase method is more practical for high voltage current transformer with higher accuracy class.The study has some reference to both design and testing engineers of high voltage current transformer.