MVDC circuit breaker: introducing our breakthrough HyBreak technology

The protection of medium-voltage direct current grids is one of the key issues standing in the way of the electrification of sectors such as mobility and industry. While solutions exist for low-voltage DC and substantial research is underway for the development of high-voltage solutions, little work has been dedicated to the medium-voltage context. At SuperGrid Institute, we have developed a medium-voltage DC circuit breaker which draws on breakthrough HyBreak technology. Be sure to come and see our scale model at PCIM Europe 2024, on our stand no. 410 in the ECPE pavilion, in Hall 6!

It is now widely accepted that electrification is one of the most important strategies for eliminating our dependence on fossil fuels and reducing our CO2 emissions.

Practically speaking, this involves:

  • Increasing low-carbon electricity generation
  • Increasing the transmission and distribution capacity of this electricity
  • Working on technologies for these new electrified uses e.g. mobility, industrial processes, and energy storage.
Medium-voltage DC circuit breaker introducing our breakthrough HyBreak technology-supergrid

The MVDC issue

Be it in contexts where DC is already used at low voltages but will need to increase to meet the demands of electrification, such as in the rail industry, or in applications where medium voltage in alternating current is currently the norm but where a switch to DC is being considered for various reasons, such as in linear photovoltaic collector networks, there is growing interest in the use of medium voltage direct current (MVDC) networks.

The control and protection of these new networks is therefore becoming a crucial issue in the pathway towards a decarbonised society. There is a need to develop fast, compact medium-voltage DC circuit-breakers, since they are crucial elements for the protection of these new applications against electrical faults.

However, no commercial solution is currently available. The use of AC technologies is impossible, as they rely on the current passing through zero, which does not happen in DC. The technology used in low-voltage direct current (LVDC), notably in the rail industry, struggles to break at higher voltages and the high-voltage direct current (HVDC) solutions are too complex and out of proportion with the breaking needs of MVDC.

At SuperGrid Institute, we have been working to develop a technology to fill this gap.

SuperGrid Institute’s HyBreak technology

Our HyBreak technology is a hybrid breaking solution using both solid-state and mechanical breaking technologies. Our MVDC circuit breaker is composed of IGBT semiconductors, and a vacuum interrupter associated with an ultra-fast actuator. Drawing on our research experience and expertise in the high-voltage domain, we have developed a hybrid solution with an electromagnetic actuator which allows us to open the vacuum interrupter very quickly, in a few hundreds of microseconds. From this action, the current switches to series connected IGBTs which then break the fault current.

“Our expertise in high voltage direct current circuit breakers (DCCB) enabled us to produce a prototype which offers an excellent compromise between on-state losses, mechanical endurance, and breaking speed. Our HyBreak breaker is reliable, produces minimal losses and offers fast breaking for maximum protection of your systems.”  Pierre-Baptiste Steckler, Research Engineer specialising in Power Electronics at SuperGrid Institute.

Medium-voltage HyBreak DC circuit breaker characteristics:

  • Voltage: ± 2.5 kV DC and higher
  • Rated current: 2 kA
  • Switching current: 6 kA
  • Internal switching: 1 msec (typical)

These characteristics correspond with our current HyBreak MVDC breaker prototype, but we are already at work making improvements! Get in touch to speak to us about future developments in MVDC breaking.