The 500kV Oil-filled Submarine Cable Temperature Monitoring System Based on BOTDA Distributed Optical Fiber Sensing Technology

The 500 kV oil-filled AC submarine cable in Hainan Networking System is the first large capacity, ultra-high voltage cross-sea submarine power cable in China, which is 31 kilometers long and bundled with a submarine optical cable. And temperature monitoring on the submarine cable is of great significance to control the current rating and ensure the operation reliability. Based on the structural characteristics and setting condition of this submarine cable, a temperature monitoring system is established in this paper based on the Brillouin optical time-domain analysis (BOTDA) technology. In this system, the optical cable is used to monitor the temperature of the submarine cable surface, and an optimized thermal circuit model is proposed to calculate the internal temperature distribution. Moreover, an onshore simulation experimental platform is established on the same cable as the Hainan Networking System for the first time, which proves the accuracy of the temperature monitoring system and the calculation method.