Multi-infeed simultaneous commutation failure risk discrimination method considering reactive voltage characteristics

The invention provides a multi-infeed simultaneous commutation failure risk discrimination method considering reactive voltage characteristics, and the method comprises the steps: calculating the voltage variation of a fault DC and a sound DC caused by an accessed fault impedance based on a node impedance matrix, calculating the reactive unbalance between AC and DC during a fault period, and calculating the reactive unbalance between AC and DC; the method comprises the following steps of: calculating voltage variation of fault direct current and sound direct current according to reactive power unbalance between alternating current and direct current, calculating voltage support quantity of the fault direct current and voltage drop quantity of the sound direct current according to reactive power transmission quantity between current conversion buses, and calculating voltage interaction factors of the multi-infeed direct current system; and calculating a critical simultaneous commutation failure factor of the s