异步联网方式下云南电网超低频振荡的机理分析与仿真

2016年云南电网与南方电网主网将实施异步联网运行方式,然而在异步联网系统试验中进行预设的直流功率提升等试验项目时发现云南电网频率出现长时间超低频率的振荡。通过大量现场试验数据分析,锁定了水电机组调速系统是造成本次振荡的直接原因,并对水电机组调速系统在振荡过程中提供负阻尼的机理进行了分析。在此基础上,利用离线数据仿真成功复现了试验过程中的超低频振荡现象,验证了理论分析的正确性,最后对下一步工作提出了初步建议。

Mechanism Analysis and Simulation on Ultra Low Frequency Oscillation of Yunnan Power Grid in Asynchronous Interconnection Mode

The asynchronous interconnection mode between Yunnan Power Grid and China Southern Power Grid is planned to be put into practice in 2016. However, during the practical experiment of raising DC power in asynchronous mode, the frequency of Yunnan Power Grid oscillates in ultra low frequency for a long period. In this paper, through detailed analysis of the experiment data, the governor systems of hydropower units are found to be the direct reason of the oscillation, and the mechanism of governor systems offering negative damping during the oscillation is analysed. Furthermore, off line data simulation is carried out to reproduce the process of this practical experiment, the results prove the correctness of the theory, finally some preliminary recommendations are proposed for further work.