Contents I. Introduction
The high voltage submarine cables, as the main power transmission channel between islands and harbors, have been widely developed, and many countries around the world have carried out various studies on them [1]. The oil-filled 500 kV submarine cable of China’s Hainan Networking System extends from Guangdong Province to Hainan Province and spans the Qiongzhou Strait, which has significant economic and social value [2]. The temperature of the submarine cable while it is in operation is an important parameter to determine its loading and evaluate its operational status [3]. As electricity demand continues to increase, the load also increases, which also leads to accretion in the operation temperature of the cable. However, excessive load and temperature will accelerate the aging of the insulating material and even cause thermal breakdown, affecting the safe and stable operation of the power system. At the same time, the insulation faults of high voltage cables are usually manifested by local temperature changes or abnormalities [4]. Therefore, establishing a temperature online monitoring system of the submarine cable is significant to clarify its loading and ensure its safe operation.
