背靠背柔性直流输电技术在中心城区电网中的应用研究

Study on Application of Back-to-back Flexible Direct Current Transmission Technology in Central Urban Grid

背靠背柔性直流输电技术,可以联结两个或多个不同的交流系统,也可以将不同的配网馈供区域以直流为母线进行联结。该技术充分应用既有交流输电线路,挖掘既有交流电网能力,通过直流母线互联进行负荷转移,从而实现负荷在既有交流电网的均衡分布;同时在故障方式下,能够智能灵活实现负荷转移,减少现有交流电网的切负荷量。在同一站址内建设整流站和逆变站,形成两端或多端柔直结构,实现多个分区互联,背靠背柔直技术可节省各端之间直流互联线路的成本,节约总占地面积以及投资。本文通过分析南京中心城区电网在“十四五”期间面临的挑战,提出了应用背靠背柔性直流输电技术解决南京中心城区电网发展问题的方案,论证了该技术在中心城区电网应用的技术优势和推广前景。

Back-to-back flexible direct-current(DC)transmission technology can not only connect two or more different alternating-current(AC)systems,but also connect the power supply area of different distribution network with DC busbar.The technology makes fully use of the existed AC transmission line and explore the existed AC network ability for load transfer by the inter-connection of DC busbar so to achieve equalization distribution of the existed AC network and,at the same time and in case of fault mode,can achieve flexibly load transfer and reduce the load shed of the existed AC network.With the construction of rectifier and inverter stations in the same site,the flexible DC transmission structure with two or more ends can be formed and inter-connection of different partitions can be achieved,the back-to-back technology flexible DC transmission technology cans save the cost of DC inter-connection line between ends,save the total land area and investment.In this paper,the solution by using back-to-back flexible direct-current(DC)transmission technology to deal with the problems in Nanjing central urban area power system is proposed by way of analyzing the challenges in Nanjing central urban area power system during the 14th-Five-Year planning period.The technical advantages and promotion prospects of this back-to-back flexible direct-current(DC)transmission technology utilized in the central-urban-area power systems is verified.