Adjustable-speed operation of doubly fed machines in pumped storage power plants

Pumped energy storage system technology and its AC–DC interface topology, modelling and control analysis: a review

“…In a variable‐speed DIFM system, the power converter is applied for regulating and controlling voltage, frequency and power flow in the network based on the standard and desired values. Basically, there are two types of AC‐to‐AC conversions in use: direct and indirect conversions [20]. A cycloconverter is used for application of direct use and an intermediate DC‐link or a back‐to‐back converter for indirect use [21].…”

“…However, a naturally commutated cycloconverter has limitations, such as performing only the down conversion of frequency [20] for sub‐harmonic‐free and efficient operation and poor input displacement power factor, particularly at low output voltages. Apart from supplying the exciting current of the generator motor rotor winding [8], faster availability, lower volume and better energy conversion ratio with faster response for load transients [24] and possibility of all kinds of grid failures ride through come to in effect in cycloconverter topology.…”

“…It has also good features such as non‐circulating current type 12‐pulse converter, capability of application in 4000 V/3000 A direct light‐triggered thyristor, protecting against overvoltage on the secondary of generator‐motor terminals, capability of generating 50 Hz three‐phase AC frequency for pumping start [8]. However, a naturally commutated cycloconverter has limitations including performing only the down conversion of frequency [20] for subharmonic‐free and efficient operation, and poor input displacement‐power factor, particularly at low output voltages.…”

“…In either of the vector control schemes, varieties of modified strategies based on the generic scheme have been developed and implemented in the application of DFIM‐based pumped storage system to ensure incremental improvement of system performances [1–11, 14, 17, 20–28, 33, 36, 38–41].…”

Variable Speed Pumped Storage Hydropower Plants for Integration of Wind Power in Isolated Power Systems

“…For most applications of pumped storage systems, only a limited controllable speed range is needed during normal operation (Bendl et al, 1999;Boquel & Janning 2003;Mori et al, 1995;Schreirer et al, 2000). This allows for obtaining variable speed operation by utilizing the concept of a doubly fed asynchronous machine (DFAM) and a power electronic converter with reduced converter rating compared to the total machine rating.…”