Systems & Electronics

 MAIG-BF  Breaker Failure

If a switchgear does not work properly when an open command is applied the Breaker Failure MAIG-BF device identifies the fault condition and send the command to open the other switchgears in order to isolate the busbar.

The Breaker Failure identifies the fault condition of the switchgear by the position of the limit switches related to the switchgear poles (signal FC52) or by the measurement of a persisting current flowing through one or more poles.

The MAIG-BF time delay to trip can be programmed to match the expected opening time of the controlled switchgear.

The MAIG-BF can detect a contact tram a relay signaling a fault condition that will prevent the switchgear to operate (e.g. SF6 low pressure); when the condition occurs the MAIG-BF will trip instantaneously to command the other


The MAIG-BF can also manage the manual opening command to the switchgear. In this case the MAIG-BF signals the fault condition without sending trip commands to other switchgears, allowing the operator to decide which switchgears to operate


The MAIG-BF module is housed in a 19″ – 4U standard rack , 340 mm. deep. The main functions of the MAIG-8F such as the detection of fault conditions and the lime delay to trip are performed by the digital overcurrent protection relay IBF4N. The protection relay IBF4N belongs to the SIGMA-N digital protection line.

The final output relay SAB (to trip other switchgears) and all the other auxiliary relays are integrated in the rack. The terminal blocks are positioned on the rear of the rack module. In figure 1 is represented the connection diagram of the MAIG-BF module.