HVDC circuit breakers are key components to enable the smooth continuous operation of HVDC grids in case of grid faults. This enables the development of multi-terminal HVDC grids to reliably and efficiently export large-scale offshore wind energy to the North Sea countries and furthers European integration by facilitating a common energy market. Thus far, the application of HVDC circuit breakers has been limited, with only partial verification by testing and little operational experience.
The 350 kV rated prototype passed a carefully developed DC fault current interruption test programme representing the full range of electrical DC fault current interruption stresses which are encountered in real operation, paving the way to standardization of these test requirements. DC fault currents up to 20 kA were interrupted with a 3 ms breaker operation time and suppression energies up to 10 MJ. The current and energy test stresses were directly supplied by a test circuit based on AC short-circuit generators operated at low power frequency.
The tests were partly witnessed by an audience of TSOs and developers and are as such an important milestone in creating confidence in the technology maturity of HVDC circuit breakers. The complete DC current interruption functionality of a full-scale, fully-rated and fully-integrated system was successfully demonstrated in an industrially relevant environment, signifying a technology readiness increase to level 7-8 (with 9 being a fully developed competitively manufactured product in operation). In addition to the tests, it was also shown that a complex system like this can be assembled in the time span of a few days which is important for the maintainability and hence availability.
The next step is the realisation of real concrete pilot projects in which the performance and benefits of HVDC circuit breakers can be demonstrated in an operational environment over a longer period of time.
You can download PDF-files of the presentations given that day here [ZIP container, 18,1 MB].