Subsea observation networks have been increasingly used to explore oceans. However, the stability of the entire system remains a crucial problem. In 2015, flashover discharge occurred in a transmission line during a sea trial in the South China Sea, thereby resulting in node destruction and serious losses. This study investigates flashover discharge in the transmission line and aims to determine its influences on the nodes. We use a damaged submarine cable to conduct a flashover discharge fault experiment and analyze the causes of this voltage change law. A cascade of lumped parameter model is adopted for the transmission line, and the optimal segment length is confirmed through simulation. Step response is applied to the study of flashover discharge, and the results agree well with the PSpice simulation results. Then, simulations and experiments on flashover discharge are conducted on the basis of the cascade of lumped parameter model. Results show that voltage surge is generated in the output side with the occurrence of flashover discharges, especially when they are continuous. An effective method of adding silicon stacks at the converter input and connecting transient voltage suppressor (TVS) in parallel at the output is proposed to suppress this oscillation.

海底观测网络已被越来越多地用于勘探海洋。但是，整个系统的稳定性仍然是一个关键问题。2015年，南海试航时输电线路发生闪络放电，造成节点破坏，损失惨重。这项研究调查了传输线中的闪络放电，旨在确定其对节点的影响。我们使用损坏的海底电缆进行闪络放电故障实验，并分析此电压变化规律的原因。传输线采用级联的集总参数模型，并通过仿真确定了最佳段长。将阶跃响应应用于闪络放电的研究，其结果与PSpice仿真结果吻合良好。然后，基于集总参数模型的级联，对闪络放电进行了仿真和实验。结果表明，随着闪络放电的发生，在输出侧会产生电压浪涌，特别是在连续放电时。为了抑制这种振荡，提出了一种有效的方法：在转换器输入端增加硅叠层，并在输出端并联连接瞬态电压抑制器（TVS）。