Variable-speed operation of hydropower plants: Past, present, and future

Abstract

In ThIs arTIcle, The sTaTe of The arT In the variable-speed operation of hydropower plants is reviewed, with a focus on pumped-storage hydropower. relevant literature is reviewed to address the benefits of variable-speed operation for both power systems and hydropower facilities. Two main configurations to enable variable-speed operation-the doubly fed induction machine (DfIM) and the converter-fed synchronous machine (cfsM)are discussed and compared. The article addresses the technology and energy policies of the past, present, and future and points out how the motivation, services, value, and technology of variable-speed hydropower plants have been subject to considerable change.

Investigation of magnetic field and radial force harmonics in a hydrogenerator connected to a three-level NPC converter

“…pole number). According to (1), the order of the main force density component is expected to be twice the order of the main flux density component (i.e. pole pair number).…”

“…To realize variablespeed operation, the following two configurations can be utilized: doubly fed induction machine (DFIM), and converterfed synchronous machine (CFSM). While CFSM has many advantages over DFIM [1,4], its drawback is the need for a fullrated converter. In DFIM configuration, the rating of the converter is reduced (around 30% of rated power).…”

“…Variable-speed operation of hydropower plants (more specifically pumped-storage plants) can be beneficial for power system and for the hydropower plant itself [1][2][3]. As an energy storage technology, variable-speed pumped-storage plants can improve the integration of renewables into the power system.…”

Effects of lifting reactance requirements on the optimal design of converter-fed synchronous hydrogenerators

“…In applications like pumped storage, where variable speed operation of the generator is desirable, the converter-fed synchronous generator topology (CFSM) seems to be the most promising [1]. With the CFSM, the generator is decoupled from the grid by the converter.…”

Analysis of magnetic forces and vibration in a converter-fed synchronous hydrogenerator

“…However, there are applications where variable-speed operation of hydropower plant can be advantageous [1]. For example, in a pumpedstorage plant, in order to adjust the pumping power, rotational speed of the motor-generator and pump-turbine needs to be varied.…”