On-load tap-changers (OLTCs) on the Great Belt HVDC connection

The task is to purchase and install vacuum diverter switch inserts for the on-load tap-changers (OLTCs) on the converter transformers on the Great Belt HVDC connection. The vacuum diverter switches are to replace the existing diverter switches that utilize conventional technology for the switching process in an oil filled chamber. The Great Belt HVDC connection is a vital link between the east and west part of Denmark. The link includes 2x3+1 converter transformers with OLTCs. We want to purchase eight vacuum diverter switch inserts for the OLTCs, seven of which are to be installed in the existing OLTCs and one of which will be kept as a spare. Currently the transformers are equipped with MR R II 1202 – 72.5/C-12221WS oil OLTCs, which are to be replaced with vacuum technology to improve the performance and reduce the maintenance costs. The diverter switch inserts must be compatible with the existing OLTCs.