风火打捆直流外送系统直流故障引发风机脱网的问题研究

Study on Wind Turbine Generators Tripping Caused by HVDC Contingencies of Wind-Thermal-Bundled HVDC Transmission Systems

随着风火打捆直流外送系统的出现及不断投运,为保证系统的安全稳定运行,需要对风电、火电、直流在无功电压方面的相互影响和作用机制开展深入研究。为此,首先分析了直流闭锁故障引发风机高压脱网的机制及应对措施,然后分析了直流换相失败引发风机高压脱网的机制及应对措施,最后探讨了风电与直流之间的相互制约关系及火电的支撑作用,采用规划的西北风火打捆直流外送系统算例进行了验证。结果表明,直流故障后的滤波器无功盈余加上风电场无功补偿电压效应是引起风机高压脱网的原因,需要对风电、火电、直流进行协调控制。研究结果可以为风火打捆直流外送系统稳定性的理论研究和工程实际提供参考依据。

As long as emergence and continual commission of wind-thermal-bundled HVDC transmission system, in order to ensure security and stability, it is necessary to carry out further study on reactive power/voltage interaction among wind turbine generators（WTGs）, thermal generators（TGs） and HVDCs. Firstly, the mechanism and corresponding countermeasures of WTG overvoltage tripping caused by HVDC blocking contingencies are analyzed. Then, the mechanism and corresponding countermeasures of WTG overvoltage tripping caused by HVDC commutation failure are analyzed. Finally, mutual restriction between WTG and HVDC and support of TG are discussed. The results are verified with the planned Northwest China wind-thermal-bundled HVDC transmission case system. The results show that the cause of WTG overvoltage tripping are reactive power surplus of HVDC converter filters and voltage effect of wind farm reactive power compensation, and coordinated control should be applied on WTGs, TGs and HVDCs. The study provides basis and reference for theoretical research and practical engineering on stability of wind-thermal-bundled HVDC transmission system.