AQ-B398 Busbar protection device
AQ300_full rack_web_2
AQ300_full rack_web_2


The AQ-B398 busbar protection device comes in two variants: the C variant (AQ-B398C) is a centralized busbar protection device, while the D variant (AQ-B398D) is a main device for distributed busbar protection applications. In distributed busbar protection applications the device communicates with bay devices using the IEC 61850-9 intercommunication standard. The bay device can be any of the AQ 300 series devices that have the incorporated busbar protection bay device functionality. AQ-B398 provides a total trip time of less than 20 ms for busbar faults.


  • Centralized busbar protection:
    • A maximum of 6 bays and 2 busbar sections in a three-phase configuration.
    • A maximum of  24 bays and 8 busbar sections in a single-phase configuration.
  • Distributed busbar protection:
    • A maximum of 24 bays.
    • A synchronizing signal with 1-ms time intervals in a distributed configuration.
AQ300_full rack_web_2

Technical data

  • Circuit breaker failure protection (CBFP; 50BF/52BF)
  • SIQuench arc quenching device (MV)
  • Distributed busbar protection (sub-unit) (optional)

  • Number of supervised trip contacts: 8
  • Current (IL1, IL2, IL3, I0)
  • Voltage (U1, U2, U3, U12, U23, U31, U0) and frequency (f)
  • Power (P, Q, S, pf) and Energy (E+, E-, Eq+, Eq-)
  • Event recorder

  • Standard
  • CPU module (MM/ST + RJ-45)
  • Power supply module (PS + fault relay)
  • Current measurement module
  • Voltage measurement module
  • Trip module (4 outputs)
  • 12 digital inputs (3x4)
  • 8 digital outputs (1x8)
  • Trip module (4 outputs)
  • Number of empty slots: 6
  • Options
  • 4-channel RTD module

  • Standard
  • CPU module (MM/ST + RJ-45)
  • Power supply module (PS + fault relay)
  • No options

  • Communication inputs
  • RJ-45 100 Mbps Ethernet + MM/ST fiber optic Ethernet
  • 2 x ST/MM redundant fiber optic Ethernet (optional)
  • ST/MM fiber optic Ethernet and RS-485 (optional)
  • LC/MM and RJ-45 (optional)
  • 2 x LC/MM (optional)
  • PRP/HSR (optional)
  • Communication protocols
  • IEC 60870-5-101/104/103
  • Modbus/RTU and Modbus/TCP
  • DNP3.0
  • IEC 61850 (optional)

  • Advanced "CyberProtect" cyber security feature (optional)

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