联于不同强度交流电力系统的VDCOL参数优化

Parameters optimization of VDCOL connected to AC power systems with different strength

研究最优VDCOL控制参数随交流电力系统强度变化的规律,分析电网的电气连接强度和直流接入方式对交流系统短路容量的影响,从系统稳定性角度解释最优VDCOL变化规律的本质.结果表明,受端电网电气长度和直流系统接入阻抗对系统短路容量影响较明显;随着系统短路比(SCR)和有效短路比(ESCR)的下降,针对换流站附近故障,系统稳定性的主要矛盾由功角稳定问题向电压稳定问题转变,最优VDCOL控制参数曲线呈右移趋势.并针对系统不同运行状态,验证该规律具有一定的普遍性.对规划HVDC接入不同交流电力系统时整定VD-COL参数具有一定指导意义.

The rule about how the control parameter of VDCOL varies with the strength of AC power system is studied in this paper. The influence of electrical connection strength and the ac- cess mode of HVDC on short-circuit capacity is analyzed in detail. The rule is explained from the power system stability point of view. Study results show that the electrical distance of the receiv- ing power system and the input impedance of the HVDC system affect the short-circuit capacity more dramatically. The stability type changes from angle stability to voltage stability for the same fault near the converter station with the decrease of the system short-circuit ratio （SCR） as well as the effective short-circuit ratio （ESCR）. The V-I curve of VDCOL shifts to the right dur- ing the decreasing. Simulation results for different operating conditions of the system show the general property of the rule. It is useful for VDCOL parameter setting when a certain HVDC sys- tem is connected to different AC power systems.