摘要
随着新能源渗透率不断地提高,电力系统惯量水平逐步下降,导致频率稳定问题愈加突出。提出一种提升新能源电力系统频率稳定性的控制策略,通过检测系统惯量中心频率变化率与系统等值惯量水平估算频率事件发生时系统的不平衡功率,并调整换流器功率参考值,为系统提供惯量支撑。所提的不平衡功率估算方法包括系统惯量中心频率变化率检测和系统等值惯量计算2部分:考虑到系统惯量中心频率曲线经过本地测量频率曲线二阶导数零点,系统惯量中心频率曲线可由二阶导数零点连接得到的分段线性曲线近似;系统等值惯量计及了系统中非同步元件的有效惯量,可通过统计系统同步惯量、发电机功率变化与不平衡功率总额获得。提出了按照新能源装机容量占比补偿不平衡功率的附加控制方法,在频率事件发生时快速调整新能源接入换流站的功率参考值,以抑制系统频率波动。PSCAD/EMTDC仿真验证了所提附加控制策略的有效性。
With the increasingly high penetration of renewable energy into the power system,the inertia level of the power system is gradually decreasing,and the frequency stability issue has become more prominent than ever before.This paper proposes a supplementary control strategy to improve the frequency stability of the renewable energy integrated power system,which estimates the unbalanced power of the system by detecting the rate of change of frequency in the center of system inertia(COI)as well as the equivalent inertia level of the system,and adjusts the referenced power of the converter to provide inertia support for ac grids.The proposed unbalanced power estimating method includes two parts:rate of change of COI frequency detection and system equivalent inertia calculation.Since the COI frequency curve passes through the zero points of the second derivative of the local measurement frequency curve,the COI frequency curve can be approximated by the piecewise linear curve connected by the second derivative zero points.The system equivalent inertia considering the effective inertia of the non-synchronized components in the system can be obtained by counting the synchronous inertia of the system,change of active power of generators,and the total unbalanced power.Subsequently,an additional control method is proposed to compensate for unbalanced power based on the proportion of the capacities of renewable energies.The referenced power value of the renewable energy station will be quickly adjusted to suppress system frequency fluctuations when a frequency event occurs.PSCAD/EMTDC simulation verifies the effectiveness of the proposed additional control strategy.
作者
张军六
李佳朋
唐震
陈秋逸
郝丽花
李宇骏
许昭
ZHANG Junliu;LI Jiapeng;TANG Zhen;CHEN Qiuyi;HAO Lihua;LI Yujun;XU Zhao(Electric Power Science Research Institute, State Grid Shanxi Electric Power Company, Taiyuan 030001, China;School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China;Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China)
出处
《电力科学与技术学报》
CAS
北大核心
2022年第3期50-60,共11页
Journal of Electric Power Science And Technology
基金
国网山西省电力公司电力科学研究院科技项目(SGTYHT/19-JS215)国家自然科学基金青年科学基金(51807150)。
关键词
新能源接入
惯量响应
附加功率控制
频率稳定
renewable energy integration
inertia response
supplementary power modulation
frequency stability
