Start-up system for pumping operation of the reversible units at the Dinerwig pumped-storage station

This article describes the design and performance of the start-up system, comprised of motor-generators and their accessory control and switching circuitry, used for initiating pumping operation in the reversible turbines at the Dinerweg pumped storage plant in Great Britain. Different variants examined for starting the turbines included starting by means of an electric motor; starting from a special starting turbine; direct asynchronous starting at the full or reduced voltage of the network; and frequency starting by means of a special variable-frequency starting device. These variants are comparatively assessed. The system selected was frequency starting for its greater reliability, suitability, cost, and adaptability to synchronous starting under emergency conditions.