UPFC潮流控制模型及控制特性研究

Study on Load Flow Control Model and Control Performance of UPFC

为定量评估统一潮流控制器(UPFC)的潮流控制能力及其对电力系统潮流分布的优化作用,提出了UPFC的潮流控制模型与潮流控制特性。研究了UPFC的主电路拓扑结构、潮流控制原理及外部功能特性,做出了UPFC的简化等效电路;采用设置功率注入附加节点的方法,提升了潮流计算的收敛性,并便于将电路模型植入潮流计算软件;分析了电路拓扑中输入、输出量的关系,完成了对UPFC潮流控制功能的稳态建模。分别研究和定义了线路潮流均衡度和系统潮流均衡度两个指标,为评估UPFC的潮流控制能力和控制效果、研究UPFC对系统潮流的优化作用提出了量化的指标依据。基于算例,计算了系统在不同运行方式下、投入UPFC前后,线路的过载情况、潮流分布均衡度指标,UPFC的响应特性、控制效果和对电力系统潮流的优化作用。算例分析结果验证了UPFC潮流控制模型的准确性和潮流优化控制功能的有效性。

Power flow controlling model and performance of Unified Power Flow Controller（ UPFC） has been studied,then the ability of power flow controlling and optimization can be evaluated quantitatively thereby. First,based on the single-line topology,power flow controlling principle and external performance of UPFC,the simplified equivalent circuit diagram is figured out accordingly. By proposing additional power injection node,the convergence of the power flow calculation with UPFC is improved and then,the equivalent circuit is also more suitable to be incorporated in the program for the power flow analysis. Also,the input and output variables of the equivalent circuit and their functional relations are studied,so the UPFC analytical model for power flow controlling can be developed. Two indices,degree of load flow balancing of lines and system（ symbolized as Kpiand Ksrespectively） are defined to evaluate the power flow controlling and optimization performance quantitatively. In the test system study,different operation modes of the power system with different load levels are considered. From comparison of Kpi,Ks,controlling performance and optimization performance of UPFC,the feasibility of UPFC power flow model and the utility of UPFC are proved.