摘要
在通信失效的情况下运行混合直流输电系统,将会面临很高的安全风险。因为在无通信的情况下发生MMC侧站内故障,将会导致子模块电容电压超过安全限值。为此提出了一种新的解决方案,在子模块端口处并联了一个旁路晶闸管,在站内故障的情况下,触发旁路晶闸管,人为地构造直流短路故障,由LCC侧的直流线路保护系统检测出该直流短路故障,并启动gate shift(GS)控制策略,从而实现子模块过电压的抑制。最后基于PSCAD搭建了一个混合直流输电模型,并仿真验证了该方案的有效性,从而保证了在通信失效的情况下仍可以安全运行LCC-MMC系统。
Running hybrid HVDC transmission system in the case of communication failure will face a high security risk. An internal station fault at MMC side without communication may cause the capacitance voltage of the submodule to exceed the safety margin. A new solution is proposed in this paper,in which a bypass thyristor is connected in parallel at the sub-module port. The bypass thyristor will be triggered and a designed DC short-circuit fault will be constructed artificially. The DC short circuit fault will be identified by the DC line protection system at the LCC side,and the GS control strategy will be triggered to suppress the over-voltage of the submodule. Finally,a hybrid DC transmission model based on PSCAD is built,and the effectiveness of the scheme is verified by simulation,which ensures that the hybrid HVDC system can be run safely in the case of communication failure.
作者
郝玉凤
孙小龙
惠艳波
HAO Yufeng1, SUN Xiaolong2, HUI Yanbo2(1.CGN New Energy Investment （Shenzhen） Co. , Ltd. , Beijing 100070, China; 2. Tongchuan CGN New Energy Co Tongchuan, Shaanxi 727000, China)
出处
《南方电网技术》
北大核心
2018年第2期114-119,共6页
Southern Power System Technology
关键词
混合直流输电系统
站内故障
电气应力
hybrid HVDC transmission system
internal fault
electrical stressing
