水下长距离电力载波通信是水下生产系统深水油气开发中应用最广泛和最经济的通信方式，深入理解和合理应用该传输技术对保证水下控制系统的长距离监控质量有重要意义。基于水下控制系统的基本构成，对长距离电力载波的机理和通信衰减的影响因素进行了研究分析，同时结合南海某水下气田实际工程项目进行了通信环路最大衰减值计算、通信有效性分析和脐带缆关键电参数要求计算。该研究为水下控制系统通信设计提供了一种有效的分析方法，为海洋工程项目通信系统的设计优化和设备选型打下基础。

Subsea long distance power line communication is the most widely used and the most economical way of communication in deepwater oil and gas development. Deep understanding and reasonable application of the transmission technology is important to ensure the quality of long distance operating and monitoring system of subsea control system. Based on the basic configuration of subsea control system, we analyze the mechanism of long distance power line communication and the influencing factors of communication attenuation. Combined with a subsea gas field project in the South China Sea, the calculation of communication loop maximum attenuation value, the communication effectiveness analysis and the calculation of umbilical key electrical parameters requirement are carried out. This study provides an effective method for the communication design of subsea control system, which lays a solid foundation for the design optimization and equipment selection of communication system of ocean engineering projects.