溪洛渡、糯扎渡直流输电规模对南方电网 安全稳定影响

考虑云南电网的负荷水平、开机方式、直流运行方式等因素，研究溪洛渡和糯扎渡直流采用5000MW或6400MW输电规模对南方电网影响，涉及南方电网的输电能力、安全稳定及电网适应性。研究结论是：直流规模越大，输电能力越高，但直流提高送电能力的比值越低；直流规模增大有利于减轻云南电网交流通道潮流，且在其他直流或交流线路发生严重故障时使云南电网处在较为稳定的状态，尽管在溪洛渡和糯扎渡直流发生双极故障时其本身需要切除的机组容量也增多。研究还表明，受端广东电网能承受这种直流规模，这种直流规模对南方电网主导振荡模式的阻尼影响也不大。

The Influence of the Capacities of Xiluodu and Nuozhadu HVDC Projects on Security and Stability of China Southern Power Grid (CSG)

Taking into account the factors of load level, generation unit commitment and high voltage direct current (HVDC) operation mode in Yunnan Power System, the 5 000 MW and 6 400 MW capacities of the Xiluodu and Nuozhadu HVDC projects are examined to have concern about the influence of the capicities on China Southern Power Grid(CSG). The study involves the transmission capacity, the security and stability, and the adaptation of CSG. It is concluded that the transmission limit of Yunnan Power System will increase as the capacities of the HVDC projects increase, but the growth rate of the total power increment relative to the HVDC component decreases at the same time; larger HVDC capacity leads to less AC power flow in Yunnan Power System, and thus can make the system more stable when serious failures occur in the other HVDC lines or AC lines though it accompanies a larger possibility to cut off more generators when the Xiluodu or Nuozhadu HVDC bipole failures occur. The study shows that Guangdong Power Grid can adapt to the HVDC capacities, and the damping of dominating oscillation mode of CSG is not much influenced by the HVDC capacities.