Microgrid MV DCCB 5 kV prototype (designed and laboratory tested)

Deliverable D3.7 of the HYPERRIDE project is a demonstration and laboratory testing of a 5 kV DC circuit breaker prototype. This report records the work done in order to achieve this goal. The requirements on the prototype’s current interruption capabilities are outlined in another task of the HYPERRIDE project and are dependent on the grid to be protected, i.e., the Medium Voltage Direct Current (MVDC) grid of RWTH Aachen. A circuit breaker based on the Voltage source converter Assisted Resonant Current (VARC) principle has been designed to meet these requirements. The VARC breaking process uses an active current injection method where a Voltage Source Converter (VSC) excites the resonant branch of the circuit breaker to produce a resonant current through the main interrupter of the breaker. The resonant current counters the line current and the net current flowing through the main interrupter momentarily becomes zero. The current to be interrupted is commutated into an energy absorbing branch of the circuit breaker where the magnetic energy stored in the protected line is dissipated. This branch also clamps the voltage across the main interrupter. This report documents the circuit breaker prototype setup and the relevant current interruption tests. Relevant details (such as largest interrupted current, breaker operation time and fault current suppression time) are also discussed. It is concluded that a functioning circuit breaker prototype suitable for protecting the Aachen MVDC grid has been designed, built and tested by SCiBreak