Combined Primary Frequency and Virtual Inertia Response Control Scheme of a Variable-Speed Dish-Stirling System

Abstract

The potential of variable-speed dish-Stirling (VSDS) solar-thermal generating plant in providing grid frequency support is investigated. In the proposed VSDS frequency support control scheme, the reference speed of the Stirling engine is regulated to track a deloaded power curve which is governed by the solar insolation level. The gain of a supplementary speed-frequency droop controller is then set to meet the primary frequency control requirement. Further uniqueness of the VSDS control scheme pertains to the provision of virtual inertia response by regulating the kinetic energy in the rotating mass of the enginegenerator and the thermal energy in the heat absorber/receivers. Small-signal analysis shows that the frequency support scheme is inherently stable, and it will provide higher degree of damping as the penetration level of the VSDS system and/or the solar insolation level increase. The efficacy of the proposed scheme is validated by computer simulation.

Comparison and Influence of Flywheels Energy Storage System Control Schemes in the Frequency Regulation of Isolated Power Systems

“…Technical solutions to improve the integration of RE in isolated systems and to avoid frequency deviations have been extensively researched. The most popular methods found in the related literature include (i) implementation of synthetic inertia and frequency control support, a very extended method in very different RE scenarios such as solar-thermal hybrid systems [18], tidal generation [19], variable-speed wind turbines and power converters [20]- [25], and even with electric vehicles connected to the grid to provide grid support services [26], [27], (ii) development of better prediction models to reduce variable RE uncertainty [28], [29], (iii) addition of real inertia by synchronous condensers [30], (iv) pump storage hydropower plants participating in frequency regulation when pumping [31]- [33] and -probably the most common option -(v) utilization of auxiliary energy storage systems [34], [35] such as batteries, capacitors, superconductors or flywheels to provide fast frequency response and inertial response.…”