For accurate test of the capacitance current of 6

3

5 kV insufficiently grounded power system to ground

a testing method was proposed

in which a capacitance current tester of distribution network is used for the test by means of the different-frequency method at open delta of a three-phase voltage transformer

and the difference of measured data of PT with load on line and without load is calculated to determine the capacitance current of the6

3

5 kV insufficiently grounded power system to ground. On-line test was conducted on 19 lines of the 6

3

5 kV distribution network in a power plant

the test data were analyzed to verify the correctness of the proposed testing method. Part of the lines were modified acco

rding to the data

and the result demonstrate the feasibility and accuracy of the proposed method.