含大容量新能源接入的柔性直流背靠背分区互联系统频率支撑策略研究  

Frequency Support Strategy for VSC-BTB Based DC Segmented System With Large Capacity Renewable Energy Integration

作　　者：王一振 邱逢良 雷鸣[1] 季一润 王成山[1] WANG Yizhen;QIU Fengliang;LEI Ming;JI Yirun;WANG Chengshan(Key Laboratory of Smart Grid of Ministry of Education(Tianjin University),Nankai District,Tianjin 300072,China;Electric Power Research Institute of State Grid Jibei Electric Power Co.,Ltd.,Xicheng District,Beijing 100045,China)

机构地区：[1]智能电网教育部重点实验室(天津大学),天津市南开区300072 [2]国网冀北电力有限公司电力科学研究院,北京市西城区100045

出　　处：《电网技术》2023年第3期959-967,共9页Power System Technology

基　　金：国家自然科学基金项目(U22B20109)。

摘　　要：在“双碳”背景下,柔性直流分区互联系统是解决负荷中心高比例消纳新能源、短路电流超标、潮流控制困难等一系列问题的有效途径。然而,随着柔性直流等电力电子装置的增多,电网逐步呈现低惯量、弱阻尼的特点,对系统频率稳定影响较大。因此提出了一种适用于含大容量新能源接入的柔性直流背靠背分区互联系统频率支撑策略。该策略基于电压下垂控制,增强了互联交流系统的惯量和阻尼,实现了负荷扰动下的功率互济和频率支持。同时,以最大程度提高频率最低点为目标优选控制参数,降低了系统低频减载风险。进一步,通过互联系统功率和直流电压的解耦控制,促使新能源场站依据直流电压偏差自适应地参与交流频率支撑。最后,在PSCAD中搭建含大容量新能源接入的柔性直流背靠背分区互联系统验证了所提出策略的有效性。To achieve the carbon peak and neutralization, the voltage source converter(VSC) based DC segmented system is an effective way to solve such problems as high renewable energy consuming, short circuit current standard exceeding, and power flow controlling of the urban power load centers. However, with the increasing application of the VSC and the other power electronics devices, the power grid gradually presents the characteristics of low inertia and weak damping, which have had a negative impact on the frequency stability. Therefore, a novel frequency support strategy is proposed for the VSC based back-to-back(VSC-BTB) DC segmented system with large capacity renewable energy integration. Based on the droop control and setpoints adjustment, the equivalent inertia and damping of both the interconnected AC systems are enhanced. The coordinated power exchange and frequency support between the segmented areas are achieved. Moreover, the control parameters are designed by improving the frequency nadir so as to reducing the risks of low-frequency load shedding. The decoupled control of power and DC voltage through the VSCs impels the renewable energy station to participate in the adaptive frequency regulation to mitigate the system frequency deviation. Finally, simulation conducted in PSCAD/EMTDC validates the effectiveness of the proposed strategy.

关 键 词：柔性直流 分区互联 新能源 频率支撑 

分 类 号：TM721[电气工程—电力系统及自动化]