occurs on the wye-connected side of the power transformer, negative sequence current
quantities appear on the delta-connected side of the power transformer.
The most common application for the negative sequence overcurrent protection is
probably rotating machines, where negative sequence current quantities indicate
unbalanced loading conditions (unsymmetrical voltages). Unbalanced loading
normally causes extensive heating of the machine and can result in severe damages
even over a relatively short time period.
Multiple time curves and time multiplier settings are also available for coordinating
with other devices in the system.
4.4.1.6
Signals
Table 233:
NSPTOC Input signals
Name
Type
Default
Description
I
2
SIGNAL
0
Negative phase sequence current
BLOCK
BOOLEAN
0=False
Block signal for activating the blocking mode
ENA_MULT
BOOLEAN
0=False
Enable signal for current multiplier
Table 234:
NSPTOC Output signals
Name
Type
Description
OPERATE
BOOLEAN
Operate
START
BOOLEAN
Start
1MRS757454 D
Section 4
Protection functions
611 series
231
Technical Manual
Summary of Contents for Relion 611 Series
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