HVDC connection to large nuclear power plants: A case study on Moorside in Great Britain

Use of HVDC links for direct connection of a large nuclear power station to the existing power grid is unprecedented. Control of such HVDC connection for stable and secure operation of the nuclear power station is challenging and untested. For the Moorside nuclear power station planned close to the Lake District in Great Britain, there is tremendous pressure to use HVDC cables for the southern connection route (which would pass through the picturesque landscape) to avoid the visual impact of overhead lines. This paper shows that it is feasible to connect a large nuclear power station, such as Moorside, through a VSC-HVDC cable route alongside a northern AC route where there are no objections to overhead transmission. Use of a proposed control of the VSC-HVDC is shown to achieve automatic and rapid redirection of power on to the VSC-HVDC link following sudden outage of the AC route. Moreover, if the generators at Moorside were to shut down accidentally, the same control strategy for VSC-HVDC can back feed the power station auxiliaries which is essential for nuclear safety. Thus, a mix of AC and HVDC connection routes achieves similar (if not better) transient responses as compared to using both AC routes which in this case faces serious opposition.