In 10 kV power distribution system

the self-excitation of the AC motor is more common during the transient process of switching the series compensation device.For the line with series compensation device

the fundamental frequency 50 Hz current and low frequency current will appear in the motor stator current and rotor current.The low frequency self-excited current will generate negative electromagnetic torque to offset the torque generated by part of the fundamental frequency current.The average electromagnetic torque of the motor is reduced and below the rated revolution and the motor cannot be used normally

causing a large current oscillation in the system.In this paper

PSCAD-EMTDC software is used to establish two typical radiant structure of 10 kV distribution network with asynchronous motor and series compensation simulation model.The self-excitation phenomena of the motor due to switching of series compensation device caused by such factors as motor capacity

load type and series and compensation capacitance is calculated and studied

the voltage

current and frequency after generation of the self-excitation phenomenon are calculated.The suppression effect of self-excitation of the motor is studied by weakening the capacitance series compensation.It is shown by the result that the self-excitation phenomenon of the motor will generate large over-voltage and over-current.The occurrence of sub-synchronous resonance can be suppressed by way of reducing the compensation degree of the series compensation device

but

on the other hand

the compensation effect of the series compensation device on the system voltage will inevitably be weakened.