直流输电系统的功率输送能力主要受所联交流系统强度的限制,单条直流系统的功率输送能力和功率稳定已有较多的研究。随着多馈入直流系统的出现,直流系统间的复杂相互作用使得多馈入直流系统的功率稳定性更为复杂。以两馈入直流系统为基础,研究多馈入直流系统运行状态变化、直流间耦合程度以及多馈入短路比大小对多馈入直流系统功率稳定性的影响。分析结果表明,在多馈入直流系统中,减小所联直流系统电流、减小直流系统间电气距离、增大所联系统多馈入短路比均能有效增大直流系统的功率稳定裕度、提高功率输送能力和最大直流功率。
The transmission capability of HVDC power transmission system is principally restricted by the strength of AC power system to which the HVDC system is connected.There are much research results on both transmission capability and power stability of single HVDC power transmission system,however along with the appearance of multi-infeed HVDC power transmission systems the complex interaction among HVDC lines makes the power stability of multi-infeed HVDC power transmission system more complicated.Based on two-infeed HVDC power transmission system,the influences of the variation of operation condition of multi-infeed HVDC power transmission lines,the coupling degree between HVDC lines and the value of multi-infeed short circuit ratio on power stability of multi-infeed HVDC power transmission system are researched.Analysis results show that for multi-infeed HVDC power transmission system the power stability margin of multi-infeed HVDC power transmission system as well as the transmission capability and maximum DC power can be effectively improved by reducing the current of HVDC system to which the multi-infeed HVDC power system is connected,reducing the electrical distance between HVDC systems and increasing multi-infeed short circuit ratio of the connected HVDC system.