地区电网火电机组超速保护定值深化研究

Further Research on Setting Values of Over-Speed Protection Controller for Fossil Power Generation Units in Regional Power Grid

地区电网孤网运行时的频率控制是维持系统稳定的重要方面,当孤网系统转动惯量小,仅依靠高周切机、低频减载等措施可能无法满足系统频率要求,还会造成火电机组OPC保护频繁动作,系统频率振荡。针对新疆石河子电网孤网后的高频问题,通过OPC各项参数的深化研究(包括OPC保护动作频率值、动作时延、关闭时间间隔以及高压阀门关闭与否等参数)、不同机组间OPC协调配合研究以及OPC与高频切机协调配合研究等,提出一整套OPC保护定值配置原则,以避免或减少孤网运行时的系统频率振荡。

Frequency control during isolated operation of regional power system is an important aspect for maintaining system stability. In view of low rotational inertia of isolated power system, the requirement to system frequency stability could not be met only by such measures as over-frequency generator tripping and under-frequency load shedding, and these measures would cause frequent action of over-frequency protection and control （OPC） device for fossil power generation units and frequency oscillation in regional power system. In allusion to over-frequency occurred in isolated Xinjiang Shihezi power system, through further research on parameters of OPC device, including the operating frequency, by which the OPC device acts, the time-delay of the action of OPC device, the time interval between adjacent shutdown of OPC device and whether the high-pressure valves are closed or not, as well as the coordination among OPC devices for different generating units and the cooperation between OPC device and high-frequency generator tripping and so on, a set of principle for OPC device configuration is proposed to avoid or alleviate the system frequency oscillation under isolated power system operation.