A Study on Multi-Frequency Coupling Effects in an Actual Sub/Super Synchronous Oscillation Event
With high penetration of renewable energy and electronic equipment in power systems,the issue of wide-band oscillation is becoming increasingly prominent.The coupling phenomenon of multi-frequency components has been observed in practical wide-band oscillations.This paper aims to reveal the mechanism and characteristics of such multi-frequency coupling effect.Firstly,the paper theoretically explains how a converter produces multi-order coupling components under voltage disturbances.Secondly,the reasons that cause the multi-frequency coupling effect in a grid-tied converter is revealed,which includes the control and coordinate transformation of phase-locked loop,inconsistent control of dq axis,and so on.Finally,the field-recorded data of two oscillation events in a certain actual power grid are analyzed to verify the accuracy of mechanism analysis.
sub/super synchronous oscillationmulti-frequency coupling effectsgrid connection converterfield-recorded data