SF system: Power conversion

This article describes the constant current, high voltage power facilities which power the SF Submarine Cable repeaters. The overall power system description includes discussions of the power connections to the cable, and a review of overall design requirements and objectives. The circuit description is covered in a general manner to demonstrate the basic concept. Particular emphasis is given to the description of several significant circuit innovations which include automatic load sharing by two constant current sources, 20 kHz inverter operation with output wave symmetry correction, solid-state alarm detectors, automatic turn-up and turn-down features, electrical noise suppression, redundant shutdown circuits and selective alarm cutoffs. The physical design includes the extensive use of plug-in modules for ease of maintenance, convection cooling of the entire power supply including the test load, and a key interlock system which prevents access to high voltage components when the power supply is energized. A special high-voltage switch can transfer the cable from one power plant to another without interruption of service.