Improved dynamic phasor model of HVDC system for subsynchronous oscillation study

Dynamic phasors have been introduced to the HVDC model to analyze its dynamic behavior. Dynamic phasor method featured by high accuracy and calculation speed has many advantages, representing the switch state of the valve with switching function and flexibly selecting the proper time-varying Fourier coefficient based on the need of actual analysis. Based on analysis of influence exerted by thyristor dead time and trigger control on the HVDC dynamic phasor model, this paper accordingly improves the dynamic phasor model which successfully interfaces with the electromagnetic transient model through the establishment of PSCAD/EMTDC custom model and is finally proved to be precise by comparison with electro transient model, consequently authenticated to be fit for HVDC SSO.