适应多端直流输电系统直流故障仿真的工程实用模型研究  

A practical model suitable for DC fault simulation of a multi terminal DC transmission system

作　　者：郑伟 国建宝 杨光源 曹润斌 聂少雄 李桂源 ZHENG Wei;GUO Jianbao;YANG Guangyuan;CAO Runbin;NIE Shaoxiong;LI Guiyuan(Maintenance and Test Center of Extra-high Voltage Transmission Company,China Southern Power Grid Co.,Ltd.,Guangzhou 510080,China;China Southern Power Grid Electric Power Research Institute Co.,Ltd.,Guangzhou 510080,China)

机构地区：[1]中国南方电网有限责任公司超高压输电公司检修试验中心,广东广州510080 [2]南方电网科学研究院有限责任公司,广东广州510080

出　　处：《电力系统保护与控制》2022年第12期180-187,共8页Power System Protection and Control

基　　金：南方电网科技项目资助“柔性直流控保系统与阀控系统之间的保护配合及控制协调优化研究”(ZBKJXM20180635)。

摘　　要：多端直流输电(Multi-terminalDC,MTDC)已经成为颇具竞争力的跨区域大功率输电技术,但因结构复杂,目前缺乏完整的数学模型。真双极混合桥模块化多电平变流器(Modularmulti-levelconverter,MMC)是特高压MTDC的重要部分。若仍沿用半桥MMC的模型建模,真双极结构中双阀组交流侧的电气联接无法体现。另外,半桥MMC模型中0-1二值开关函数推广到混合桥的合理性也有待证明。为解决MTDC建模中存在的上述问题,以昆柳龙直流工程为例,首先推导真双极混合桥MMC的完整数学模型,并对常规高压直流换流站和直流传输线进行准稳态和集中参数近似。进一步建立了直流故障下MTDC的工程实用数学模型,兼顾了精确性和复杂性。最后针对直流单极接地故障运用该模型进行分析计算,并与PSACD仿真结果进行对比,验证了所提出模型的有效性。Multi terminal DC (MTDC) has become a competitive cross-regional high-power transmission technology,but there has been little research on its complete mathematical model because of its structural complexity.A true bipolar hybrid bridge modular multi-level converter (MMC) is an important part of ultra-high voltage MTDC.If its mathematical model still adopts the simple half-bridge MMC,electrical connection on the AC side of the true bipolar MMC cannot be reflected.Also,the rationality of extending the 0-1 binary switching function of the half-bridge MMC model to the hybrid bridge has yet to be proven.To solve the above-mentioned problems in MTDC modeling,Kun-Liu-Long DC project is taken as an example.First,the complete mathematical model of the true bipolar hybrid bridge MMC is deduced,and the quasi-steady state and lumped parameter approximation of conventional HVDC converter stations and DC transmission lines are carried out.Then,both accuracy and complexity are considered to establish a practical engineering model of MTDC under a DC fault.Finally,the DC unipolar ground fault is calculated and analyzed using the proposed model.Compared with the calculation results of PSACD,the validity of the proposed model is verified.

关 键 词：多端直流输电 模块化多电平变流器 真双极混合桥 电磁暂态仿真 昆柳龙直流工程 

分 类 号：TM721.1[电气工程—电力系统及自动化]