MVDC link in a 33 kV distribution network

The performance of a 33 kV distribution network with a proposed medium-voltage DC (MVDC) link between the island of Anglesey and the mainland in North Wales was assessed. The MVDC link, which will be constructed as part of the Ofgem Electricity Network Innovation Competition project ANGLE-DC, was simulated under a wide range of demand and generation, with control strategies based on real-time data from the three 132/33 kV grid transformers (GTs) that supply the island network or the wider supervisory control and data acquisition (SCADA) system. The active power set points of the MVDC link for the GT data-based control were determined by a sensitivity analysis of the network losses. For a wider SCADA system-based control, optimal set points were obtained using an optimal power flow method. The network losses and hosting capacity of distribution generation (DG) were assessed considering both normal network and N−1 conditions. This study found that the use of the MVDC link increased the DG hosting capacity of the network, but network losses might be increased or reduced depending on the load and generation conditions, and control strategies.