66kV交流交联聚乙烯电缆线路改为直流运行的直流载流量

DC Ampacity of 66 kV AC XLPE Cable Line Transformed into DC Operation

将交流电缆线路改为直流运行是提高电缆线路输送功率的有效途径之一,确定交流电缆的直流载流量对电缆的交流改直流运行意义重大。为此,采用解析法和数值法分析了空气中敷设66 kV电压等级交流交联聚乙烯(XLPE)电缆的直流载流量,开展了直流载流试验;同时采用数值法计算了直埋敷设2根平行排列交流电缆的直流载流量,并计算了电缆改为直流运行后的输送功率。计算结果表明:对于空气中敷设的交流电缆,采用解析法和数值法得到的直流载流量与试验测试结果基本一致(780 A);直埋敷设交流电缆的直流载流量约为710 A;当交流电缆改为直流运行的工作电压取57 kV时,其输送功率和原交流系统相等。上述结果验证了解析法在计算高压(66 kV)电缆直流载流量时的适用性,同时为后续66 kV交流电缆线路改为直流运行奠定了基础。

Transforming the AC cable line into DC operation is one of the effective ways to improve the transmission power of the cable line, and determining the DC ampacity of AC cable has a major significance. Therefore, DC ampacity of the 66 kV AC XLPE cable directly laid in the air is calculated by adopting analytic method and numerical method, and a DC load test is carrried out. Meanwhile the DC ampaeity of AC cable is determined by using numerical method, which are directly buried installation and laid in parallel arrangement, and calculating the transmission power of DC operation. The calculating results show that, for the AC cable laid in the air, the data obtained by analytic method and numerical method agree with the experimental result, that is 780 A. The DC ampacity of AC cable directly buried installation is about 710 A. When the operating voltage of DC operation is 57 kV, the transmission power is equal to the original AC system. The research results can verify the applicability of analytic method in calculating the DC ampacity of 66 kV volt- age level cable, and also lay the groundwork for the transformation of the 66 kV AC cable line into DC operation.