适用于两电平电压源型换流器的直流故障清除辅助拓扑  

Assistant Topology with DC Fault Clearing Capability for Two-level Voltage Source Converter

作　　者：蓝童琨 李银红[1,2,3] 段献忠[1,2,3] 罗强[1,2,3] 陈朝晖 LAN Tongkun1＇2＇3, LI Yinhong1,2,3, DUAN Xianzhong1,2,3, LUO Qiangl＇2＇s, CHEN Zhaohui4(1. State Key Laboratory of Advanced Electromagnetic Engineering and Technology （Huazhong University of Science and Technology, Wuhan 430074, China; 2. Key Laboratory of Electric Power Security and High Efficiency of Hubei Province （Huazhong University of Science and Technology, Wuhan 430074, China; 3. School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 4. Power Dispatching and Control Center of China Southern Power Grid, Guangzhou 510623, China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),湖北省武汉市430074 [2]电力安全与高效湖北省重点实验室(华中科技大学),湖北省武汉市430074 [3]华中科技大学电气与电子工程学院,湖北省武汉市430074 [4]中国南方电网电力调度控制中心,广东省广州市510623

出　　处：《电力系统自动化》2018年第7期50-55,101,共7页Automation of Electric Power Systems

摘　　要：两电平电压源型换流器在35kV及以下电压等级输电场合具有较高的成本效率比,因此被广泛应用于风电并网等低压领域。但是,其不具备直流故障清除能力的特点,给电网设备安全造成了较大的影响。基于以上背景,文中提出了适用于两电平电压源型换流器的直流故障清除辅助拓扑。该辅助拓扑使用超导故障电流限制器,大幅降低了故障电流;基于电流谐振的思路,可实现在电流过零时将故障清除。采用该辅助拓扑的直流故障清除方案,相比于采用交流断路器的方案,具有清除时间短、故障电流小的优点;相比于采用直流断路器的方案,具有电压变化率小、成本低的优点。最后,在PSCAD/EMTDC中验证了所提辅助拓扑的正确性与有效性。The two-level voltage source converter （VSC） has a high cost-efficiency ratio in the electric transmission occasion of 35 kV and below voltage level, so it is widely used in the low voltage area such as wind power integration. However, its incapability of DC fault clearing brings the great challenge to the operation of grid facilities. Based on the above background, this paper proposes an assistant topology with DC fault clearing capability applied for two-level VSC. The DC fault current is drastically reduced by the assistant topology using the superconducting fault current limiter （SFCL）. Based on the current resonance method, the fault is cleared when the fault current oscillates to zero. When employing the proposed topology, the DC fault clearing time is shorter and the fault current is lower compared with the fault clear scheme employing AC circuit breaker. In addition, it has the advantages of smaller voltage change rate and more cost saving in engineering compared with the scheme employing DC circuit breaker. Finally, the correctness and effectiveness of the proposed topology are verified in PSCAD/ EMTDC.

关 键 词：直流故障清除 两电平电压源型换流器 超导故障电流限制器 故障特性 

分 类 号：TM46[电气工程—电器]