VSC-HVDC for Frequency Support (a review)

Abstract

To reduce CO2 emissions produced by electricity generation, conventional fossil fuel power plants are being decommissioned. Renewable energy sources (RES) and interconnectors are replacing these old power plants but have different operating characteristics. A key concern as the conventional fossil fuel power plants are displaced is the reduction in system inertia. A reduction in system inertia will require faster control schemes to be implemented to prevent frequency and rate of change of frequency (ROCOF) limits from being exceeded. Frequency response schemes that can emulate inertia, often called synthetic inertia, are required and this will necessitate the need for fast controlled devices. VSC-HVDC is a desirable interface option for the power levels and controllability required to provide synthetic inertia. This paper reviews supplementary frequency control schemes applied to VSC-HVDC and co-ordinated control strategies applicable to HVDC connected systems and islanded systems.

Overview of Frequency-Control Technologies for a VSC-HVDC-Integrated Wind Farm

“…Among articles giving overviews of FR techniques for the VSC-HVDC, reference [25] introduced some coordinated FR strategies by means of discussion, but does not include the control diagrams of these methods. Reference [26] summarized the inertial control, droop control, proportional integral (PI)-based control, and their modified controllers for FR in a VSC-HVDC system. The authors in [27] proposed a classification of inertia control strategies for the VSC-HVDC based on the type of synchronization with the grid and the coordination between other generation sources: synchronized with and without phase-locked-loop (PLL), centralized control, and distributed control.…”

Grid Supporting VSCs in Power Systems with Varying Inertia and Short-Circuit Capacity

“…By taking advantage of the ability of power electronics to respond fast using a P-f droop characteristic for HVDC-VSC interconnections becomes a feasible solution to provide frequency support in AC systems with low inertia. It has been demonstrated that this is an efficient approach for reducing the maximum frequency deviation in such systems [7], [8]. In [7], a review of supplementary local control strategies for VSC-HVDC for low-inertia and islanded systems is presented.…”

“…It has been demonstrated that this is an efficient approach for reducing the maximum frequency deviation in such systems [7], [8]. In [7], a review of supplementary local control strategies for VSC-HVDC for low-inertia and islanded systems is presented. In [9], In [8], a frequency control scheme for VSCs, which are part of an HVDC grid connecting asynchronous AC systems, is proposed.…”

Dual‐loop SFC scheme for BTB‐VSC‐HVDC interconnecting asynchronous AC grids

“…At present, many references have investigated the use of conventional VSC‐HVDC to provide frequency support for the AC system [5]. Junyent et al .…”