Parameters
Configure the parameters under Configure > Parameters > Local > 4th current input > Neutral inverse time over-current.
Table 3.65 Default parameters
Parameter Range
Neutral inverse time
over-current
Curve See the reference IEC Inverse
Limit (the set point, also known as LIM) 2 to 200 % of nominal current (4th current input) 30 %
Time multiplier setting (TMS) 0.01 to 100.0 1.0
Threshold 1.0 to 1.3 1.1
k (only used if custom curve is selected) 0.001 s to 2 min 0.14 s
c (only used if custom curve is selected) 0 s to 1 min 0 s
alpha (α, or a) (only used if custom curve is
selected)
0.001 to 1 0.02
Enable Not enabled, Enabled Enabled
Latch Not enabled, Enabled Enabled
Alarm action Trip [Breaker]
More information
See Source AC protections, Inverse time over-current (ANSI 51) in this chapter for the calculation method, the
standard curves, and information about the definite time characteristic.
3.7 ACM voltage measurement errors
3.7.1 [Source]/[Busbar] L1-L2-L3 wire break
Controller types: GENSET, SHAFT generator, SHORE connection and BUS TIE breaker controllers
These alarms alert the operator to a voltage measurement failure:
• [Source] L1-L2-L3 wire break
• [Busbar] L1-L2-L3 wire break
The controller only activates the alarm when all of these conditions are met:
• The generator breaker is closed
• Voltage is detected by one set of ACM voltage measurements
• No voltage is detected on all three phases for the other set of ACM voltage
measurements
0
1
Time
Busbar
L1-L2-L3
Wire break
L1 L2 L3
Generator
voltage
L1 L2 L3
Busbar
voltage
Parameters
Configure > Parameters > [Source] > AC setup > Multiple phase wire break
DESIGNER'S HANDBOOK 4189340911K UK Page 87 of 521
To Next Page
Loading...
