单回路高压电缆金属护套最优分段比

Optimal Segmentation Ratio of Single-circuit High-voltage Cable Metal Sheath

高压单芯电缆护套接地电流过高带来的损耗严重影响电缆使用寿命以及载流量.文中通过建立高压电缆金属护套交叉互联方式下的等效电路模型,分别计算感应电流和容性电流,采用向量叠加得到接地电流,求出三相护套总损耗.分析计算了不同布置方式和段长下护套接地电流引起的损耗值.计算结果表明:单回路高压电缆金属护套采用交叉互联方式时,三分段等长且布置方式相同时损耗远小于混合布置方式;混合布置方式时损耗受布置方式的影响,选择合适的分段比可使护套损耗相比于段长相等时降低35%左右.

The sheath loss caused by the high ground current of the high-voltage single-core cable sheath seriously affects the service life and current carrying capacity of the cable.This paper establishes an equivalent circuit model under the cross-bonding mode of high-voltage cable metal sheaths,respectively calculates the induced current and capacitive current,and then vector superimposes the ground current to obtain the total loss of the sheath.The loss caused by the grounding current of the sheath under different arrangement and length is analyzed and calculated.The calculation results show that when the single-circuit high-voltage cable metal sheath adopts the cross interconnection method,the loss is much smaller than the mixed layout when the three sections are of equal length and the same layout;the loss is affected by the layout when the mixed layout is used.Choosing a suitable segment ratio can reduce the sheath loss by about 35%compared to when the segment length is equal.