摘要
新能源占比较高的新型电力系统,将主要因大规模压缩火电机组使系统固有转动惯量显著降低、因大量投入新型快速功率调控措施使系统等值惯性分布显著改变。面对新系统环境,亟需提升惯性评估模型和方法的适用性。为此,提出一种仅基于频率轨迹信息计算电力系统等值惯性时间系数(equivalent inertia time coefficient,EITC)的方法。首先,定性分析了影响EITC时空分布特性的主要因素;其次,拓展了惯性系统动力学方程一阶模型,将多种调控措施综合作用后的功率变化量等效处理为一阶模型中的时变参数EITC,并由此建立了EITC指标与频率轨迹间的定量关系,定义了EITC瞬时增益和时窗平均指标;第三,依据低频减载和频率变化率(rate of change of frequency,Ro CoF)标准提供的关键信息,基于一类特殊单交流同步机系统,提取了它的基准惯性时间常数及对应的基准暂态频率跌落轨迹。以基准跌落轨迹为统一标尺,只需采集不同电气位置的频率轨迹信号,即可实现对系统EITC分布状况的动态评估与薄弱环节的辨识。算例表明,所提方法能够评估新型电力系统在多种电源和惯性/频率调控措施综合作用后的EITC时空分布情况,可为进一步优化各类电源和调控措施的电网布局与运行策略提供技术支撑。
The inherent rotary inertia of the new power system with renewable energy as its main body will be significantly reduced mostly due to the large-scale reduction of the thermal power, and the distribution of the equivalent inertia will also be changed due to the large-scale investment of new rapid power control measures. Facing this new system environment, it is urgently needed to improve the applicability of the inertia evaluation models and methods. Therefore, an evaluation method of the equivalent inertia time coefficient(EITC) for the power system based on the frequency trajectory is proposed. Firstly, the main factors affecting the space-time distribution characteristics of the EITC are qualitatively analyzed. Secondly, by extending the first-order model of the inertial system dynamic equation, the active power changes after the comprehensive actions of the multiple control measures are equivalently treated as a time-varying EITC in the first-order model. On this basis, the quantitative relationship between the EITC and the frequency trajectory is established,and the instantaneous gain and the time-window average indexes of EITC are also defined. Furthermore, referring to the key information provided by the standards of the Under-frequency Load Shedding and the Rate of Change of Frequency(Ro Co F), and based on a special single AC synchronous machine system, its reference inertia time constant and the corresponding reference transient frequency drop trajectory are extracted. Taking the reference transient frequency drop trajectory as a unified ruler, the dynamic assessment of the EITC’s distributions and the identification of the weak points can be achieved by only collecting the frequency trajectory information at different electrical positions. Simulations show that the space-time distribution characteristics of the EITC in the new power system with comprehensive actions of the multiple power sources and the inertia/frequency control measures can be evaluated by the proposed method. This method also provi
作者
方秋实
于继来
郭钰锋
FANG Qiushi;YU Jilai;GUO Yufeng(School of Electrical Engineering and Automation,Harbin Institute of Technology,Harbin 150001,Heilongjiang Province,China)
出处
《电网技术》
EI
CSCD
北大核心
2023年第2期435-445,共11页
Power System Technology
基金
国家自然科学基金项目(51877049)。
关键词
新型电力系统
转动惯量
等值惯性时间系数
频率轨迹
时空分布特性
new power system
rotary inertia
equivalent inertia time coefficient
frequency trajectory
space-time distribution characteristics
