大截面高压电缆导体交流电阻的优化

Optimization of AC Resistance of Large Cross-section High-voltage Cable Conductor

由于集肤效应的影响,大截面高压电缆导体的交流电阻远大于直流电阻,不仅会导致电缆线路的载流能力降低,还会产生更大的线路损耗。为解决该问题,通过分析电缆导体集肤效应的产生原理和影响因素,探索降低导体交流电阻的措施,试制了不同设计结构的导体样品,并采用电压电流相位差法对样品进行交流电阻测量研究。结果表明:截面积为800 mm2的电缆分割导体的交流电阻比紧压圆形结构降低了约7.5%;截面积≤1 600 mm2的瓦楞形分割导体与扇形分割导体的交流电阻相差不大;采用单线绝缘可以有效降低交流电阻,其中漆包单线比氧化单线对交流电阻的降低效果更明显,但前者的生产成本和安装成本更高;对于紧压圆形和分割导体,同向绞合均比异向绞合结构更能有效降低交流电阻,适当提高紧压系数和增加单线根数也均能降低交流电阻。

Due to the influence of skin effect, the AC resistance of large cross-section cable conductor is remarkably higher than the DC resistance, which reduces the current carrying capability of cable line, and produces more loss of transmission line. To this end, we analyzed the generation principle and the influence factors of skin effect of cable con- ductor, and explored the measures to reduce the AC resistance of cable conductor. Through the design and trial-production, we obtained many conductor samples with different structures, then tested and analyzed the AC resistance of conductor sample using the voltage-current phase-difference method. The test results show that the AC resistance of segmental conductor is reduced by about 7.5% than that of round compacted structure with 800 mm2 cross-section, and the AC resistance of corrugated segmental conductor is as much as that of the sector segmental conductor on 1 600 mm2 and lower cross-section. The AC resistance can be effectively reduced by using insulated wire, in which enameled wire is more obvious than oxidized wire, but the corresponding costs for production and installation will be improved. Moreover, compared with the incongruous stranding, the syntropy stranding in wire layers will reduce the AC resistance more efficiently; and appropriately improving the compression coefficient and wire number can also reduce the AC resistance.