In order to study the voltage interaction and the multi-infeed interaction factor of the AC/DC parallel power system and multi-infeed HVDC, the solving method for the voltage interaction and multi-infeed interaction factor was proposed by analyzing the impedance characteristic of asynchronous motor, characteristic equations of converter stations and the increment of node power on the basis of the incremental form of power flow equation. It was pointed out that the equivalent impedance of asynchronous motor is a function of voltage, the voltage interaction relationship among nodes is related to the structure and operating state of the whole system and control mode of the DC system, and the ratio between increments of node voltage is a constant approximately. Finally, the effectiveness and accuracy of the voltage interaction formula were verified by a specific case.
