Design consideration for frequency containment reserve provisions by a multi‐terminal HVDC system

Abstract

AbstractFrequency control is considered to be an important function of multi‐terminal HVDC (MTDC) systems. Sharing frequency containment reserves (FCRs) among interconnected AC systems using HVDC technology is particularly attractive in the European context. However, coordination of the contribution between systems with different sizes, quality requirements, and dynamic characteristics requires harmonized rules and well‐defined control strategies. If the controllers are not properly designed, they can lead to disproportional supports, noncompliance with the existing regulation framework, or even degradation of the frequency quality. This paper presents a general analytical methodology for assessing the compliance of MTDC grid control solutions to the essential requirements of the FCR framework, and then examines three different implementation solutions as illustrative examples to validate the method. Through this process, the interaction mechanisms behind each solution are analytically clarified. The performance analyses are then confirmed using load‐frequency models of CE, Nordic, and GB systems coupled with a three‐terminal DC system. It is revealed that, while certain control solutions result in insufficient performance with respect to the desired FCR provision, the newly proposed distributed solution for each pair of converters is the most compliant with the existing framework thanks to the highest degrees of freedom.