220kV四回高压电缆同相2根并联敷设方式优化研究

Optimal Layout of the 220 kV Quadri-circuit Cables with Double-split Conductors in Each Phase

为了研究220 kV四回高压电缆同相2根并联的最优敷设方式,笔者根据高压单芯电缆的等值电路模型,通过软件编程,计算分析了220 kV四回高压电缆同相2根并联在"品字形"、"水平交叉"敷设方式下的芯线电流、电流分布的不均匀系数以及护套环流。在此基础上,提出了一种优化的敷设方式,即采用"品字形—水平交叉"复合式的敷设方式,并与前两种方式进行分析、比较。结果表明:在"品字形"敷设方式中,具有电流分布不均匀系数大而护套环流小的特点;在"水平交叉"敷设方式中,具有电流分布不均匀系数小而护套环流很大的特点;在优化后的"水平交叉—品字形"复合式敷设方式中,兼具电流分布不均匀系数小和护套环流小的优点。尤其是当电缆按相序BCAABC排列效果最优,电流分布的不均匀系数的最大值为1.041 0,最小值仅为1.010 3。护套环流的最大值为61.89 A,最小值仅为9.14 A。

To optimize the layout of the 220 kV quadri-circuit cables with double-split conductors in each phase, an equivalent circuit model of the cables based on the structure of single core XLPE cable is established to calculate the circuit parameters, such as the circulating current in sheaths and the nonuniformity coefficient of current distribution for triangle and horizontal cross layouts. Subsequently, an optimal triangle-horizontal cross layout of cables are put forward and compared with the above two layouts.The results show that： 1for the triangle layout, the nonuniformity coefficient of current distribution in same phase is large, while the circulating current in sheaths is small; 2 for the horizontal cross layout, the nonuniformity coefficient of current distribution in same phase is small, while the circulating current in sheaths is high; and 3for the triangle-horizontal cross layout, both of the nonuniformity coefficient and the circulating current are small. Particularly, when the arrangement of the cables is in the sequence BCAABC,the nonuniformity coefficient can get to its maximum 1.041 0 and the minimum 1.010 3, and the circulating current get to the maximum 61.89 A and the minimum 9.14 A.