NEPTUNE Power System: Science Node Converter Startup Operations Design and Implementation Circuit

The North-East Pacific Time-series Undersea Networked Experiments (NEPTUNE) is an underwater power and communications network for scientific experiments. It is proposed for the ocean floor of the Juan de Fuca tectonic plate in the Northeast Pacific Ocean. The NEPTUNE power system is a 10 kV dc network. In the science nodes connected to the NEPTUNE network, 10 kV to 400 V dc-dc converters are used to power various scientific instruments and underwater vehicles. The focus of this paper is the startup circuit design and its implementation. The configuration of the NEPTUNE power system is introduced and the challenges of the system resulting from its location on the seafloor are addressed. A set of operations designed to start the 10 kV converters, which includes the control of the 10 kV switches connecting input power cables to converters, checking converter internal faults, and the starting of these converters, is described using a logic sequence diagram. The concept is tested and results are provided.