Test methods of mutual impedance and coupling capacitance of transmission lines in parallel

The invention relates to test methods of mutual impedance and coupling capacitance of transmission lines in parallel. The test method of mutual impedance comprises the following steps that: a head end of one phase test line in a test line accesses a pilot frequency testing voltage and the end of the phase test line is grounded; the head end voltage, the head end current and the end current of the phase test line are tested and a voltage power frequency component and a current pilot frequency component are calculated; a head end voltage and a head end current of one phase operation line in an operation line are tested and a voltage pilot frequency component and a current power frequency component are calculated; and according to the current pilot frequency component and the voltage pilot frequency component, the mutual impedance between the phase test line and the phase operation line is calculated. According to the test methods provided by the invention, mutual impedance and coupling capacitance of transmission lines in parallel can be accurately tested under the circumstances that the lines are operated and there is no power failure, thereby improving test efficiency and accuracy.