中蒙直流输电工程送端孤岛频率控制问题

蒙古煤电资源通过中蒙直流输电工程直接送往我国华北电网京津唐负荷中心地区,直流输电系统送端采用"孤岛"运行方式。针对直流系统故障、受端地区交流系统故障后出现的送端频率快速上升问题,研究了利用安全稳定控制系统、机组高周切机保护、直流频率控制解决送端系统频率问题的有效性,并提出上述措施间协调配合的控制方案。仿真分析表明,利用综合控制手段能够较好地解决送端系统频率稳定问题,提高系统的稳定性。

Frequency Control for Islanded System at Sending Terminal of HVDC Power Transmission from China to Mongolia

The electric power generated by pithead power plants in Mongolia will be transmitted to load center of North China power grid, i.e., Beijing―Tianjin―Tangshan area, through China-Mongolia HVDC project. The isolated island operation mode is used for the AC power system at the sending end of HVDC system. To cope with the rapid frequency increase at sending end caused by monopole block of HVDC system or post-fault operation condition of AC system at receiving area, the effectiveness of the measures to solve frequency increase at sending end, such as security and stability control system, generator over-speed protection control and DC additional control is researched, and a control scheme coordinating above-mentioned measures is proposed. Simulation results show that the frequency stability can be well solved by comprehensive control means and the stability of power grid can be enhanced.