现役交流XLPE电缆配电线路改为直流运行的技术方案及实例分析

Technical Scheme and Case Study of the Uprating Renovation of Existing XLPE Cables From AC Distribution System to DC Operation

近年来,随着新型发电及用电技术的发展,以及对电力供应可靠性和容量要求的提高,直流配用电与直流微电网技术日益获得广泛关注。该文针对一条现役35 kV交联聚乙烯(XLPE)交流电缆线路在发生二次故障后的改造工程,创造性地提出将其改为直流运行的方案,并针对方案中所确定的±10 kV直流电压、150 A额定电流运行参数,自行设计对电缆性能进行全面校核的试验方法。在送检电缆样段顺利通过所有试验项目并完成必要的系统改造后,将电缆线路投入直流±10 kV电压下作双极运行。线路在改造后至今已安全运行4年。与传统的修复运行、新增线路等备选方案相比较,从经济性、工程性、可靠性等多方面,改直流方案均具有明显的优势,而且研究还显示其存在大幅增容的潜力。该文的研究可为国内XLPE电缆直流配网系统建设以及现役交流电缆线路改为直流运行提供理论借鉴及工程参考。

Along with the development of new technologies in power generation and application, as well as increasingly higher demand on the reliability and capability of power supply, DC distribution and micro-grid technology has received wide attention. In this paper, the renovation project for a single-circuit XLPE cable line after the second failure under 35 kV AC operation was presented. In this creative scheme, the existing XLPE cable line was put into bipolar VSC DC operation, with the voltage of 10 kV and the rated current of 150 A. The test methods for the cable performance check under designed DC scheme were put forward and carried out on sample sections. After the success of the cable test and the installation of necessary equipment, the line was put into DC operation. Till now it has been running for 4 years without any interruption. Compared with other alternatives for AC operation, such as fault reparation or new installation, this choice shows remarkable advantages in aspects of economics, reliability and engineering, and the system capacity could be further increased. The research provides an important theoretical and engineering reference for system construction of XLPE cable distribution network and uprating renovation of existing cable lines from AC to DC operation.