Description   
2.8 Electronic trip unit ETU 
  3VA27 molded case circuit breakers & 3WL10 air circuit breakers 
56  Manual, 10/2018, L1V30499596002-01 
 
Protection functions of the electronic trip units 
 
Short-time-delayed short-circuit 
—  ●  ●  ●  ● 
Instantaneous short-circuit protec-
●  ●  ●  ●  ● 
Ground-fault protection (GF) 
Enhanced protection functions 
 
Making current release (MCR)
1)
Current unbalance protection (I-
—  —  —  ●  ● 
DAS protection - arc fault mitigation 
—  —  —  ●  ● 
Ground fault return (G
ret
)
1)
2nd parameter set (set A/B) 
 
 
Residual current protection (Rc) 
2)
Direct short-time protection (DST) 
Voltage unbalance protection (V-
NBA) 
—  —  —  ●  ● 
Undervoltage protection (V
u
Overvoltage protection (V
o
Underfrequency protection (f
u
Overfrequency protection (f
o
) 
Reverse active power protection 
—  —  —  ●  ● 
Phase sequence check L1-L3 
COS PHI protection (alarm/trip) 
  Breaker Connect module required for auxiliary power supply 
2)
  Summation current transformer (Rc CT) and rating plug (Rc) required to permit the protection function