29
EATON
www.eaton.com
Voltage Imbalance Protection
Voltage imbalance protection enables protective actions based on
the imbalance value between the three line voltages. The intelli-
gent controller measures the voltage imbalance. When the voltage
imbalance is greater than the action threshold, the protection will
act; when the voltage imbalance is less than the return threshold,
the alarm action will return.
Action characteristics: When voltage imbalance is greater than
the action threshold (1), an alarm or trip delay will be activated; At
the end of the action delay time (2), an alarm or trip signal will be
issued, and voltage imbalance fault protection will act; When the
execution mode is set as alarm, after the alarm action, the return
delay will be activated when the voltage imbalance is less than
the return threshold (3); At the end of the return delay time (4),
the alarm will be removed and the voltage imbalance fault protec-
tion will return.
Emax: The maximum difference between line voltage and average
value.
Uavg: The average value of the RMS sum of the three-phase line
voltages.
Action threshold
2% ~ 30% (Step is 1%)
Action delay time (s)
0.2 ~ 60 (Step is 0.1)
Return threshold
2 ~ start value (Step is 1)
This set point is only available when the execution mode is "Alarm",
and the return value must be greater than or equal to the start value.
Return delay time (s)
0.2 ~ 60 (Step is 0.1)
Action or alarm characteristics
(Delay tolerance ±10%)
Actual voltage imbalance value / set point
1.1
Fixed time action or alarm
Actual voltage imbalance value / set point <0.9
No action or alarm
Voltage imbalance alarm return characteristic
(Delay tolerance ±10%)
Actual voltage imbalance value / set point
0.9
Return
Actual voltage imbalance value / set point >1.1
No return
Alarm contact output
When the execution mode is alarm, the "voltage imbalance alarm" contact output can be added
Demand protection
It is mainly used for process controlling need. When the demand
current of a certain phase is greater than the action threshold set
point, the circuit breaker will trip or send out an alarm signal after
the action delay time (fixed time action). Then, if the demand cur-
rent of this phase is less than the return threshold set point, the
circuit breaker will remove the alarm signal after the return delay
time (fixed time action). The current demand protection function
can be set to Enabled or Disabled. When enabled, it includes
sending an alarm signal or tripping.
Action threshold
(0.2~1.0) x I
n
(Step is 2)
Action delay time (s)
15 ~ 1500 (Step is 1)
Return threshold (A)
0.2I
n
~ start value (Step is 2)
This set point is only available when the execution mode is "Alarm",
and the return value must be greater than or equal to the start value.
Return delay time (s)
15 ~ 3000 (Step is 1)
Action or alarm characteristics
(Delay tolerance ±10%)
I / set point
1.1
Fixed time action or alarm
I / set point <0.9
No action or alarm
Demand protection alarm return characteristics
(Delay tolerance ±10%)
I / set point
0.9
Return
I / set point >1.1
No return
Alarm contact output
When the execution mode is alarm, the "demand current protection alarm" contact output can be added
U
unbal
=
|E
max
|
×100%
U
avg
U
avg
=
(U
12
+U
23
+U
31
)
3
Voltage imbalance is calculated as below:
Instruction Leafl et
Effective September 2022
IZM6 Series Air Circuit Breaker
Operating Instruction Leafl et