计及过渡电阻影响的直流电网不同拓扑结构故障电流简化计算方法  

Simplified Calculation Method of Fault Current in Different Topological Structures of DC Grid Considering the Influence of Transition Resistance

作　　者：辛业春 罗鑫[1] 王拓 王延旭 王威儒 江守其 XIN Yechun;LUO Xin;WANG Tuo;WANG Yanxu;WANG Weiru;JIANG Shouqi(Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology(Northeast Electric Power University),Ministry of Education,Jilin 132012,Jilin Province,China)

机构地区：[1]现代电力系统仿真控制与绿色电能新技术教育部重点实验室(东北电力大学),吉林省吉林市132012

出　　处：《电网技术》2023年第2期804-814,共11页Power System Technology

基　　金：国家自然科学基金项目(U2066208)。

摘　　要：故障电流计算是直流电网设备选型、参数设计和保护整定的基础,目前以详细电磁暂态仿真为主的故障电流分析方法难以适用于大规模直流电网,为此,研究能够适用于不同拓扑结构的直流电网故障电流通用计算方法。首先分析双端直流系统故障后各回路故障电流的耦合机理,提出依据回路电感参数指标的故障回路解耦方法;基于能量守恒的原则,提出网络元件串并联等效和多端环状网络解环的方法,将多端网络解环为开环网络,然后统一等效为双端的故障网络,利用所提出的故障回路解耦方法获得故障电流时域解析式。在RT-lab仿真平台中搭建了多种拓扑结构的仿真系统对所提出的方法进行验证,结果表明,所提出的方法对不同拓扑的直流电网均具有很好的适用性,与详细电磁暂态仿真相比,计算的电流误差基本小于5%。Fault current calculation is the basis for equipment selection, parameter designing and protection setting of DC power grids. However, it is difficult for present methods of fault current analysis based on detailed electromagnetic transient simulation to apply to large-scale DC power grids. For this reason, a general calculation method is studied to be applied to fault currents of a DC grid with different topologies. First, the coupling mechanism of the fault currents in each loop after the double-terminal DC system failure is analyzed. A fault circuit decoupling method is proposed based on the loop inductance parameter index;based on the principle of energy conservation, the series-parallel equivalent of network components and the unlooping of the multi-terminal ring network are put forward. In the method, the multi-terminal network is de-looped into an open-loop network, which is uniformly equivalent to a double-terminal fault network;and finally, the fault current decoupling method is used to obtain the time-domain analytical formula of the fault currents. A simulation system with a variety of topologies is built on the RT-lab simulation platform to verify the proposed method. The results show that the proposed method has good applicability to DC grids with different topologies,and is compatible with detailed electromagnetic transients.Compared with the detailed electromagnetic transient simulation, the proposed method has got basically less than 5%of the calculated current error.

关 键 词：多端直流电网 故障电流计算 过渡电阻 等效并联 网络解环 

分 类 号：TM721[电气工程—电力系统及自动化]