HVDC DYNAMIC CHARACTERISTIC ANALYSIS BASED ON SAMPLED-DATA MODEL

This paper use sample-data modeling method to obtain the small-signal linear model of HVDC including 12-pulse converter. The model considers the dynamics of converter switch circuit and can be applied in the analysis for high frequency dynamic characteristics. With this model, the influences of HVDC control system and the ac system on HVDC dynamic characteristics, especially the high frequency dynamics, are analyzed, the results show that the SCR of inverter AC system has considerable impact on HVDC dynamic characteristics, too small SCR of inverter AC system can lead to low-frequency instability; the high gain of rectifier control will have adverse effect on high-frequency stability; the low-frequency and high-frequency stability will become worse with constant extinct angle (CEA) control in inverter. At last it is proved that conventional quasi-steady model of HVDC can not be suitable for analysis of high frequency dynamics in power system.