Protection against Transient Overvoltages Caused by Intermittent Earth Faults in Unearthed Marine Power Distribution Networks

Intermittent earth faults may create overvoltage issues in unearthed and high-resistance earthed marine power distribution networks. Protection measures should be arranged to avoid equipment failures by limiting the overvoltages. This paper presents transient overvoltage analyses caused by intermittent earth faults in the unearthed marine networks. With an electrical model of a LNG carrier that is chosen to study, overvoltages are calculated under different fault durations, network configurations, and fault locations. Moreover, this paper discusses the effect of surge arresters in overvoltage mitigation and discharging energy. The study result shows that the proper installation of the protective device allows for managing the overvoltage level and energy within devices' ratings.