NEPTUNE: dc power beyond MARS

The modular power converter designed for the Monterey Accelerated Research System (MARS), and recently successfully tested by the Jet Propulsion Laboratory (JPL) and the University of Washington, is a significant milestone in the development of regional cabled observatories. The ability to transmit up to 10kW reliably over long distances using 10kV direct current (dc) and convert it to a more usable 400V dc locally will open up new possibilities for the science community. For future projects covering several hundreds of kilometers and using multiple power converters, high reliability will be crucial. Some evolution of the design is therefore essential. The intention for the NEPTUNE project is to build on the MARS achievements to the point where the converter is a fully industrialized unit built to submarine telecom standards. The JPL/MARS system includes a redundant converter available via a medium voltage switch. With relatively minor circuit changes the converter reliability can be increased so that a single converter could be more reliable than two and a switch.