Load Acceptance And Load Shedding - Load Management - Siemens 3VA1 100 A Manual

Description
2.8 Electronic trip unit
2.8.4

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.
①
②
③
④
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 t
100
Incoming alarm "load shedding"
Outgoing alarm "load shedding"
Parameter load shedding 400 A
Current in one phase
from 1 s to 15 s.
x
⑤
Parameter load acceptance 100 A
⑥
Incoming alarm "load acceptance"
⑦
Outgoing alarm "load acceptance"
Manual, 04/2015, A5E03603177010-02
3VA molded case circuit breakers