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Load acceptance and load shedding - load management

3VA molded case circuit breakers equipped with an ETU 3-series or higher series provide two current thresholds for the purpose of implementing a local load management function. Load shedding is the upper threshold, and load acceptance the lower threshold.

NOTE

No trip

Tripping is never initiated as a result of the current value crossing the upper or lower thresholds.

If the current in one phase exceeds the parameter setting for "load shedding", an incoming alarm "load shedding" is generated. Only when the current in all three phases drops below this threshold is an outgoing alarm "load shedding" generated.

The incoming and outgoing alarms can be output via an optional EFB module and transferred via the communication link.

The opposite applies for the load acceptance threshold. If the current in all three phases drops below the parameter setting, an incoming alarm "load acceptance" is generated. If only one of the three currents exceeds the parameter setting, an outgoing alarm "load acceptance" is generated.

To prevent these alarms being generated by brief current peaks and troughs, they can be delayed by the time tx from 1 s to 15 s.

Incoming alarm "load shedding"

Parameter load acceptance 100 A

Outgoing alarm "load shedding"

Incoming alarm "load acceptance"

Parameter load shedding 400 A

Outgoing alarm "load acceptance"

Current in one phase

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