HUW1
Series Intelligent Universal Circuit Breaker
16
Electrical diagram of residual current protection
6.4.10
Overvoltage protection
The intelligent controller measures the effective value of the primary circuit voltage. When all three
phase-to-phase voltages (line voltages) are greater than the set value, that is, when the minimum value of the three
line voltages is greater than the set value of the overvoltage protection, the overvoltage protection acts; when the
minimum value of the three line voltages is less than the return value, the alarm action returns.
Action threshold (V)
Return threshold
– 1,200 (step length: 1)
Action delay time (s)
0.2
–60 (step length: 0.1)
Return threshold (V)
100
–action threshold (step length: 1)
This set value is only available when the execution mode is
"Alarm", and the starting value must be greater than or equal to
the return value.
Return delay time (s)
0.2
– 60 (step length: 0.1)
Action or alarm
characteristics
(delay tolerance±10%)
U
min
/action threshold
≥1.1 Fixed time action or alarm
U
min
/action threshold <0.9 No action or alarm
Overvoltage alarm return
characteristics
(delay tolerance±10%)
U
max
/action threshold
≤0.9 Return
U
max
/action threshold >1.1 No return
Alarm contact output
When the execution mode is
“Alarm”, the "Overvoltage Alarm" contact output can be added
6.4.11
Voltage imbalance protection
Voltage imbalance rate protection acts according to the imbalance rate between three line voltages. The
intelligent controller measures the voltage imbalance rate, and performs protection action when the voltage
imbalance rate is greater than the action threshold; when the voltage imbalance rate is less than the return threshold,
the alarm action returns.
Action threshold
2%
– 30% (differential: 1%)
Action delay time (s)
0.2
– 60 (differential: 0.1)
Return threshold
2%
– Starting value (differential:
1%)
This set value is only available when the execution mode is "Alarm",
and the return value must be less than or equal to the starting value.
Return delay time (s)
0.2
– 60 (differential: 0.1)
Action or alarm
characteristics
(delay tolerance±10%)
Actual voltage imbalance rate/set value
≥1.1 Fixed time action or alarm
Actual voltage imbalance rate/set value <0.9 No action or alarm
Voltage imbalance alarm
return characteristics
(delay tolerance±10%)
Actual voltage imbalance rate/set value
≤0.9 Return
Actual voltage imbalance rate/set value >1.1 No return
Alarm contact output
When the execution mode is
“Alarm”, the "Voltage Imbalance Alarm" contact output can be added
6.4.12
Phase sequence protection
Phase sequence detection is taken from the primary voltage. When it is detected that the phase sequence is the
same as the setting direction of the starting value, the protection action is instantaneous. When one or more phases
of voltage do not exist, this function will automatically exit.
Setting range of action phase
sequence
∆φ: A, B, C/∆φ: A, C, B
Alarm contact output
When the execution mode is
“Alarm”, the "Phase Sequence Fault Alarm" contact output can be
added
Protection execution mode
Alarm/trip/shutdown
Transformer
Intelligent
controller
Intelligent
controller
Transformer
RCD: Zero sequence
current transformer
R: Ground resistor