HVDC Circuit Breaker Performance Demonstration

A European offshore HVDC grid could provide significant benefits to the European energy market and facilitate decarbonisation. HVDC circuit breakers are key equipment for the protection of such grids against the consequences of faults. However, the TRL (Technology Readiness Level) of HVDC circuit breakers needs to be increased towards the full prototype performance demonstration level. PROMOTioN is currently carrying out full-power testing demonstrations, where test facility (KEMA Laboratories of DNV GL) and three manufacturers (Mitsubishi Electric, ABB and SciBreak), all project partners, cooperate in this undertaking. In work package 5, test-circuits and methods were designed and demonstrated. In work package 10, these methods and circuits are actually used to demonstrate the TRL of three technologies of HVDC circuit breakers.

The first technology fully demonstrated is a circuit breaker based on the active current injection principle (such breakers are also known as ‘mechanical HVDC circuit breaker’), manufactured by Mitsubishi Electric, represented by Mitsubishi Electric Europe B.V. (MEU) in the PROMOTioN project. In an earlier stage of the project, a smaller MEU HVDC circuit breaker was used to demonstrate the suitability of the method and test circuits used. Test guidelines were agreed upon among the work package partners, based on research work (described in D10.3, D10.4) on critical stresses on HVDC circuit breakers.

During a test campaign in June 2019, carried out at KEMA Laboratories of DNV GL in the Netherlands, experts used the power of multiple AC generators and step-up transformers to emulate a fault in a HVDC grid. For the complete testing of HVDC breakers – as opposed to HVAC breakers –, a very large amount of direct power (megawatts) is needed to verify the energy absorption capability of the test object.

A double break 160-200 kV HVDC circuit breaker unit, with a potential for upgrading to 525 kV, successfully limited a rapidly rising fault current to 16 kA within 7 ms after which the system started to recover. The testing was witnessed by numerous stakeholders from the project consortium and beyond on June 20, 2019.

Following the guidelines on test requirements agreed upon within PROMOTioN, current interruption tests at load current and 10 % of the load current were also carried out successfully.
These tests were the first in the world to actually apply all relevant stresses during the current interruption process in a single test. As such, demonstration of test facilities and proof of this HVDC circuit breaker technology are major achievements on the way towards the safe and secure operation of offshore HVDC grids.

Two other HVDC circuit breaker technologies will be demonstrated in the first half of 2020. After the completion of all demonstrations, the results will be published in project deliverable D10.7.