At present, no dc circuit-breaker is commercially available and any dc fault will affect the entire dc network. A dc grid is, therefore, restricted to a single protection zone at present and the capacity of generation connected to it may not exceed the infrequent infeed loss risk limit prescribed by the Security and Quality of Supply Standard. The dc circuit-breaker is therefore an essential technology in enabling the concept of a dc grid to develop.
The objective of the proposed work is to understand the application issues associated with dc circuit-breakers in dc grids. The work will study the impact of dc circuit-breaker operation on the dc system, the HVDC converters and the connected ac systems. In particular, the challenges presented by protection and fault clearance in dc grids will be addressed. The work forms an essential component of the risk-managed introduction of the dc circuit-breaker onto the transmission system in accordance with PS(T)013. The results of the work will inform technical specifications and risk-registers for the dc circuit-breaker and for the protection and control of dc grids.
The project will deliver reports on the results of studies of the system behaviour and the results of experiments performed on a model (low voltage simulation) dc circuit-breaker in the analogue HVDC test facility at Cardiff University. The work complements a closely-related project at the University of Manchester which aims to study the electrical operating environment of the dc circuit-breaker and derive design and test requirements for the device itself.