An enhanced static converter with integrated energy storage for pumped storage plants

Abstract

This study investigates an enhanced static frequency converter (E-SFC) for pumped storage hydropower. The proposed solution is built on the static frequency converter (SFC) used in pumped storage plants (PSPs) to start the system in pump mode. It offers a new degree of freedom with an embedded energy storage. It aims at allowing hydropower plants to reach new, fast ancillary services, but also to mutualize equipment to achieve cost savings. The investigated converter is based on back-to-back neutral point clamped (NPC) converters and allows one of its two inverters to operate either as an ac-dc converter (i.e., classical starter mode) or as a dc-dc converter to connect an energy storage system as supercapacitors. Firstly, the proposed upgrade is described. Secondly, a control strategy is developed to enable the system to connect a dc energy source to an ac grid. Then, the simulations, with a detailed modelling of the E-SFC, validate the concept and the proposed control scheme.

Florian Errigo, Laurine Turpin, Florent Morel.

Presented at IET PEMD 2024