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Solid State DC Breakers

DC links are ideal for integrating multiple power sources and storage systems where the size and weight of AC generators and transformers are undesirable. However, high power DC links cannot be safely deployed without effective DC-breakers which must interrupt the current within microseconds.

Astrol Electronic DC breakers are designed for integrating DC-grids and protecting against short-circuit currents. Various voltage and current levels are realized using a modular structure and different configurations based on 3.3 kV, 4.5 kV and 6.5 kV Insulated Gate Bipolar Transistor (IGBT) and diode modules.

  • Up to 1500 V DC
  • Fast fault interruption – (uS response)
  • Liquid or air cooled
  • Bi-directional current flow
  • For high or low side power switching
  • Current ratings from 200 A to 5 kA
  • Switch-off current up to 20 kA

Water-cooled DC breakers

DC Link CurrentDC Link VoltageWeight
AA-21000-0020.5 kA1 kV49 kg
AA-21001-1101.5 kA1 kV95 kg
AA-21002-1002.25 kA1 kV154 kg
AA-21002-0013.0 kA1 kV154 kg
AA-21002-0033.0 kA1 kV154 kg
AA-10411-1010.5 kA1 kVSmall
AA-10411-1021.25 kA1 kVMedium
AA-10411-1032.5 kA1 kVLarge
AA-10411-1043.75 kA1 kVLarge
AA-10411-1055 kA1 kVLarge

Air-cooled DC breakers

VoltageNominal currentSize (D x W x H)Maximum Weight
AA-10718-xxx1.5kV200A383mm x 490mm x 307mm22kg

Rapid fault interruption

With a time constraint of microseconds, local fault protection must be performed autonomously by the switch control system without the need for external control or fault detection. In addition to rapid over-current protection, the breaker can be programmed to open according to a time-current profile. This allows the overall system to reconfigure the behavior of the DC-Breaker within certain pre-defined boundaries. The fast opening time limits the fault current and minimises the negative impact on the load – the current does not reach damaging levels and can be interrupted without forming an arc. Voltage reversal is therefore not required.

Block diagram

Self-diagnostics and control interface

The internal self-diagnostic capability of the DC breaker units includes the gate drive unit as well as coolant temperature and pressure at both inlet and outlet. The standard interface to the overall controller is optical Modbus-TCP. However, other protocols are available on request.


  • DC-Voltage Capability up to 1500 V
  • Current rating 0 – 5 kA
  • Switch-off current up to 20 kA
  • Very short off time in μs range
  • Totally isolated to the main grid
  • Can be used in high or low side power switching
  • Bidirectional current flow
  • Liquid cooling
  • Internal self-diagnostic capability
  • Gate Drive Unit
  • Water In- and Outlet Temperature
  • Water In- and Outlet Pressure
  • Interface to overall controller
  • Optical (Glass or Plastic)
  • Modbus-TCP
  • Other protocols on request
  • DNV-GL type approval (pending)

Operational modes:

Normal switch ON – Current flows in both directions without exceeding any boundaries
Normal switch OFF – No current flow
Emergency switch OFF – Abnormal conditions: Short in external circuit, Overload of the switch due to high external current, Temperature too high, Water cooling insufficient, Pressure loss, Water leakage
Balancing ON – Before switching ON a balancing of the voltages on both sides can be made to reach equilibrium.


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