高比例水电多直流送端电网频率稳定协调控制技术及实践

针对异步联网运行后,高水电占比多直流外送西南电网面临的超低频振荡和频率失稳风险,构建了高比例水电多直流送端电网频率稳定控制框架。在传统控制措施基础上引入直流频率控制和紧急调整功能,提高送端电网频率稳定防御能力。基于直流频率控制器对送端电网频率响应特性的影响分析,提出了直流频率控制器与一次调频的配合关系以及考虑直流功率偏差的二次调频方法。提出了兼顾频率稳定和故障后潮流控制的多直流协调紧急功率调制方案。并通过实际故障后交直流协调控制系统实际动作情况,论述了频率稳定协调控制技术的有效性。

Frequency stability coordination control technology and practice of a multi-DC outgoing power grid with a high proportion of hydropower

There is an ultra-low frequency oscillation and frequency instability risk faced by the Southwest Power Grid with its large proportion of hydropower and multi-DC outgoing. Thus a frequency stability control framework for this situation is constructed. Using traditional control measures, the functions of DC frequency control and emergency adjustment are introduced to improve the frequency stability defense capability of the outgoing power grid. Based on the analysis of the influence of a DC frequency controller on the frequency response characteristics of the outgoing power grid, the coordination relationship is considered between the DC frequency controller and primary frequency modulation and secondary frequency modulation considering DC power deviation. A multi-DC coordinated emergency power modulation scheme considering both frequency stability and power flow control after a fault is proposed. Given the actual operation of a AC/DC coordinated control system after actual fault, the effectiveness of the frequency stability coordinated control technology is discussed. This work is supported by the Science and Technology Project of the Headquarters of State Grid Corporation of China (No. 5108-201926029A).