对于电缆来说，由于电缆本身结构及敷设方式和环境的限制，造成电缆的输送能力提高比较困难。为解决上述问题有必要采用电缆扩大容量的措施。电力电缆大容量化方案很多，但从目前状况看导体大截面、降低交流电阻、降低介质损耗等手段目前经过多年的研究，技术上基本已达到极限，很难期望近年会有重大突破；在现阶段，采用强迫水冷却为一种相对造价低廉、效益好的方法。本文通过对隧道内高压电缆水冷却系统的建模分析及计算，结果表明电缆采用外部水冷却方式对电缆载流量的提高是十分显著的，在实际工程中有应用价值。同时本文亦对水冷却系统的组成、占用空间及运行维护等工程实际问题进行了探讨，为今后工程中的实际应用做了技术储备。

Because of the limit of the structure and the environment of the power cable, it is very difficult to raise the capacity of the cable. In order to solve such problems, it is necessary to use the special measures to increase the capacity of cable. Although there are many measures to expand the capacity, using the water cooling system is the comparably cheap, effective technique. This paper analyses the water cooling system of cable in the tunnel, the result of analysis indicates that the cooling system will raise the capacity notably and it has the practical value in the project. On the other hand, the paper discusses not only the composition and space of the cooling system, but also the running and maintenance of the system. All results of this paper can be used as the technical reserves for the practical application.