Reduction in the Humber
Gateway transmission system
from 6 February 2018 to 22 March 2018 was caused by an exceptional event
according to the UK regulator, Ofgem. Operated by Humber Gateway OFTO Limited,
the system delivers electricity ashore for the Humber
Humber Gateway OFTO Limited confirmed that the export cable failed due
to damage onshore, inside a duct made of polypropylene pipe. Deposits indicated
that the fault had started in the cable and was not caused by damage outside
of the duct. The investigation by the cable manufacturer found that ‘the
fault is due to a relatively small diameter indentation made to the exterior
of the cable’ and that the ‘damage must have occurred pre installation
as it would not have been possible for something to perforate the HDD duct
and remain undetected’.
Ofgem stated 'Given this, we accept that the Licensee could not reasonably
have been expected to identify the fault during the due diligence process
prior to asset transfer, and that the root cause of the event was beyond
the reasonable control of the Licensee. We therefore consider that the
claim constitutes an Exceptional Event.'
Ofgem went on to point out that two significant delays occurred during
the repair. 12 days were lost in total. It took the OFTO four working days
to conclude that not all of the switchgear earths had been disconnected,
after which they contacted the manufacturer for advice. It then took a
further ten days before the manufacturer agreed to visit the site to investigate
the earthing issue.
located in the UK North Sea, approximately 8km off the coast of the East
Yorkshire. The project consists of 73 MHI Vestas V112-3.0MW
turbines and has a maximum output of 219MW.
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