North Sea Wind Power Hub Feasibility Study: Methodology For Protection Design (part II)

An innovative concept of hub-and-spoke has been proposed by North Sea Wind Power Hub (NSWPH) consortium to combine electricity transmission from wind farms to shore with interconnectors. The hub-and-spoke are based on elementary block types in bipolar configuration at rated voltage of 525 kV with dedicated metallic return and are used in association to build the distributed hub scenarios. The scope of this paper is to present the methodology that has been used to design the DC protection for the proposed study case. Several busbar topologies and protection components have been evaluated in term of total cost (CAPEX plus OPEX) considering AC system constraints as well as different type of faults. Electro Magnetic Transient simulations for the DC grid under DC faults are also presented in this paper to validate the protection strategy and sizing of protection components.