基于Carson理论和EMTP的220 kV多回电缆线路电气参数及不平衡度分析

为分析珠澳电网220 kV电缆线路电磁不平衡问题,应用理论计算(Carson理论)与仿真(EMTP)相结合的方法。首先,对"导线—大地"回路与Carson线路理论得到的线路阻抗矩阵与EMTP仿真得到的线路阻抗矩阵进行对比。然后,利用EMTP搭建的完整实际线路模型,分析了不同因素对线路电气参数的影响程度。最后根据电磁不平衡度理论计算了相间距离、护套交联方式及相序排列3个因素对电缆线路的影响。结果表明:Carson线路模型在分析线路阻抗时误差很小与EMTP基本吻合;电缆金属护套交联和接地电阻对电缆序阻抗有一定影响;相间距离和金属护套交联影响线路负序不平衡度;在研究的这条珠澳电缆线路里,当采取ABC/CBA相序排布时线路的电磁不平衡度可以达到最低。

Analysis of electrical parameters and unbalance factors of 220 kV multi-circuit transmission cable based on Carson theory and EMTP simulation

To analyze the electromagnetic unbalance factor of 220 kV transmission cable line in Zhuhai-Macao Power Grid, this paper applies a method which incorporates Cason theory and electromagnetic transient simulation (EMTP) simulation technique. Firstly, the comparison of cable impedances derived from Carson theory and EMTP simulation is conducted. Then, according to the EMTP simulation model from one practical transmission cable line, impact factors of cable electrical parameters are analyzed. At last, calculations from three different factors (distance between phases, cross-bonding mode of metal sheath and arrangement of phases) are made to obtain the main cable electromagnetic unbalance factor. Results show that there only exists small cable line impedance errors between the Carson model and EMTP analysis. Analyses demonstrate that the metal sheath cross-bonding and ground resistance of the cable would partly impact the cable sequence impedance. The metal sheath cross-bonding and the distance between phases show great influence on the negative-sequence unbalance factor. For the analyzed transmission cable line between Zhuhai and Macao, when using ABC/CBA cable arrangement, the electromagnetic unbalance could be the minimum. This work is supported by National Natural Science Foundation of China (No. 51707047), Science and Technology Program of Guangdong Power Grid Co. (No. GDKJQQ20161098), and Science and Technology Project of Shenzhen (No. JCYJ20170811154143968).