Multi-terminal DC networks and meshed DC grids have been advocated by transmission utilities, industry and academe, as a potentially more cost effective means of integrating offshore renewable energy than point-to-point links. National Grid’s Electricity Ten Year Statements and the European Network of Transmission System Operators for Electricity’s Ten Year Network Development Plan as well as studies by The North Seas Countries’ Offshore Grid Initiative all support this view.
To realize such HVDC networks, DC circuit breakers are necessary to isolate faulted DC sections. The unacceptable alternative would be to temporarily de-energise the whole DC network to then allow isolation of the faulted section. This is unacceptable because the resulting simultaneous loss of supply to the AC system would radically exceed onshore network design limits and would lead at least to severe disruption among consumers. For larger DC grids and power loss it would even cause widespread black-outs.
While manufacturers of VSC HVDC have suggested solutions, opportunities still exist to develop faster, smaller, cheaper solutions to enable offshore location of circuit breakers and allow multi-terminal HVDC offshore wind park integration.
This EPSRC-funded project (EP/L021552/1) is investigating novel designs integrating the circuit breaker with fault current limiter technology, which may thus be capable of achieving these size, speed and cost transformative targets.
Relevant publications are available online.
Prof Mike Barnes
University of Manchester