Reliability Evaluation of an HVDC Transmission System Tapped by a VSC Station

Reliability evaluation of multiterminal HVDC systems has received very little attention in the past. This paper presents reliability modeling and analysis of an HVDC transmission system incorporating a voltage-sourced converter (VSC) tapping station. The use of VSC tapping stations enables the supply of power along the route to areas with comparatively little consumption. In this paper, a comprehensive detailed reliability model is developed and then converted to a manageable and computationally efficient model. Using this equivalent reliability model, various reliability indices are calculated at the load point of the system and the impacts of the VSC tapping station on these indices are illustrated. Sensitivity analyses are conducted to investigate the impacts of the load level and the location of the tapping station on the reliability indices. The conducted studies are numerically applied on a typical HVDC system and thorough discussions are presented.