Basler DGC-2020 Instruction Manual page 95

CT secondary side (DGC-2020). When a single-phase override contact input is received by the DGC-
2020, the overcurrent protection settings automatically switch from the three-phase settings to the single-
phase overcurrent protection settings.
When any of the phase currents increase above the pickup setting
time delay, an overcurrent condition is annunciated. An overcurrent annunciation can be user-selected to
B
trigger a pre-alarm (warning) or alarm
configured to close a programmable output.
The overcurrent time delay is controlled by a time dial setting
be set at F (fixed) or one of 16 inverse time characteristic curves can be selected. When the fixed curve
setting is selected, the time dial setting determines the overcurrent time delay with no regard to the
generator current level. When one of the inverse time characteristic curves is selected, the time dial
setting, along with the level of measured generator current, determines the overcurrent time delay. As
overcurrent protection settings are entered in BESTCOMSPlus, a plot
created to illustrate the overcurrent pickup curve. The available time characteristic curves are listed below
and illustrated in Appendix A, Time Overcurrent Characteristic Curves.
•
A, standard inverse
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A, standard inverse
•
B, very inverse
•
C, extremely inverse
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D, definite
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E1, extremely inverse
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E2, extremely inverse
•
G, long inverse
•
I1, inverse
A low-line scale factor setting
applications that may utilize more than one type of genset connections. The scale factor setting is
implemented when the DGC-2020 senses a contact closure at a contact input programmed to activate
scaling of the protection settings. The value of the scale factor setting serves as a multiplier for the pickup
settings. For example, if a scale factor contact input is received by the DGC-2020 and the scale factor
setting is 2.000, the pickup setting will be doubled (2.000 × PU).
G
The graph can be set to display the 1 Phase or 3 Phase curve as determined by the settings on the left
side of the chart.
BESTCOMSPlus overcurrent protection settings (DGC-2020, Generator Protection, Overcurrent) are
illustrated in Figure 4-37. The 51-1 element is shown.
9400200990 Rev I
B
(shutdown). An overcurrent annunciation can also be user-
•
•
•
•
•
•
•
•
•
F
is used to automatically adjust the overcurrent pickup settings in
DGC-2020 BESTCOMSPlus Software
A
for the duration of the overcurrent
C D
and a curve setting . The curve setting can
E
of the settings is automatically
I2, inverse
I2, inverse
L1, long inverse
L2, long inverse
M, moderately inverse
S1, short inverse
S2, short inverse
V1, very inverse
V2, very inverse
4-39