ABB UNITROL 1020 - Page 64

Chapter 3 - Device Overview 
56 3BHS335648 E82 UNITROL 1020 User Manual
Used for heavy load applications in island operation to unload the engine in order to
recover faster to nominal speed.
Ie Minimum current limiter
Limiter-
characteristics
P [W]
Q+ [var]
Iemin
GENERATOR
MOTOR
U
M
2
Xq
Reactive power
Active power
overexcited
underexcited
Q-
- Minimum limit
- Limiter active
Minimum [%]
Active = True/False
Ie Maximum current limiter
Hold time
[%]
[s]
Hold time
1st limit
2nd limit
Contin. current
Excitation current
- 1
st
limit
- Hold time
- 2
nd
limit delay
- Hold time
- Continuous current
Limiter active
Maximum [%]
Maximum Hold Time [s]
Delayed [%]
Delayed Hold Time [s]
Continuous [%]
Active = True/False
Cool-down behavior
In case Ie Limiter is hit short after Ie Limiter was released, the 1
st
limit hold time will be
reduced in order not to overheat the winding, where the reduction of Limiter times is
depending on the time Ie actual was running below 100%.
PQ Limiter
The characteristic is determined by 5 points
P [W]
Q+ [var]
P=100%
P=75%
P=50%
P=25%
P=0%
P=25%
P=50%
P=75%
P=100%
Active power
Reactive power
Q-
Generator
Motor
overexcitedunderexcited
- Q limit at P = 0%
- Q limit at P = 25%
- Q limit at P = 50%
- Q limit at P = 75%
- Q limit at P = 100%
- Voltage dependency
active
- Limiter active
Minimum Q(P @ 0%) [%]
Minimum Q(P @ 25%) [%]
Minimum Q(P @ 50%) [%]
Minimum Q(P @ 75%) [%]
Minimum Q(P @ 100%) [%]
Volt.Dependency:True/False
Active = True/False
UM Limiter (only in PF / Var mode)
- Limiting value of the minimum machine voltage
- Limiting value of the maximum machine voltage
- Limiter active
- Limiter active
- With active limiter, AUTO SP is taken from the
operation point prior to fault condition
Minimum [%]
Maximum [%]
Minimum Active = True/False
Maximum Active = True/False
FRT AUTO SP Hold enable =
True/False