环网中计及距离保护时限特性的电压暂降随机评估  

Stochastic Evaluation of Voltage Sag Considering the Time Characteristic of Distance Protection in Meshed Network

作　　者：陈礼频[1] 肖先勇[2] 汪颖[1] 刘旭娜[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065 [2]智能电网四川省重点实验室(四川大学),四川成都610065

出　　处：《四川大学学报（工程科学版）》2013年第3期112-119,共8页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(50877049);四川省科技支撑计划资助项目(2010GZ0256)

摘　　要：为准确刻画环网中距离保护对电压暂降特征的影响,提出了综合考虑系统环网特性和距离保护时限特性的电压暂降随机评估方法。从距离保护实际动作原理出发,经短路计算确定距离保护动作时间,根据环网线路两端距离保护动作时间判定是否发生多级电压暂降,通过修正节点阻抗矩阵确定多级电压暂降幅值,并基于电压损失量的概念将多级非矩形暂降等效为矩形暂降。对250节点系统的仿真结果表明,作者提出的方法能有效量化距离保护时限特性对电压暂降幅值和持续时间的影响,且能避免对多级电压暂降的过估计,相比传统方法更符合系统实际运行情况。In order to accurately describe the impact of distance protection on voltage sag characteristic in meshed network, a novel voltage sag stochastic evaluation method was proposed with the consideration of meshed network topology characteristic and distance protection op eration characteristic. Based on the operation principle of distance protection, the protection operation time was determined according to shortcircuit calculation result. Comparing the operation time of distance protection at each end of the line,whether or not a fault will lead to a multistage voltage sag could be confirmed. The magnitude of multistage voltage sag was determined by modifying nodal impedance ma trix, and multistage voltage sag was converted to rectangular voltage sag based on the concept of loss of voltage. The proposed method was applied to a 250bus test system, and the simulation results showed that the proposed method could quantify the impact of distance protec tion operation time on voltage sag magnitude and duration, and overestimation of multistage voltage sag could be avoid. Compared with the traditional method ,the proposed method was more accordant to practical power system operating condition.

关 键 词：电压暂降特征 环网 距离保护 时限特性 多级暂降 随机评估 

分 类 号：TM74[电气工程—电力系统及自动化]