Basler Electric BE1-11t - Manual (Page 91)

9424200995 Rev H 79
Parameter Description Explanation
C
Coefficient specific to
selected curve
Affects the multiple of PU where the curve would approach
infinity if allowed to continue below pickup. Has greatest effect on
curve shape near pickup.
N
Exponent specific to
selected curve Affects how inverse the characteristics are. Has greatest effect
on curve shape at low to medium multiples of tap.
K Constant Characteristic minimum delay term.
T
R
Time to reset Relevant if 51-x function is set for integrating reset.
R
Coefficient specific to
selected curve
Affects the speed of reset when integrating reset is selected.
Curve coefficients are entered on the Inverse Overcurrent (51) settings screen in BESTCOMSPlus.
Programmable curve coefficients can be entered only when the P curve is chosen for the protection
element from the Curve drop-down menu.
Table Curves
BESTCOMSPlus is used to set the 51 element Table Curves (T1, T2, T3, and T4). Using the Settings
Explorer within BESTCOMSPlus, open the Protection, Current, Table Curve (1, 2, 3, or 4) tree branch and
select the table curve to be modified. Refer to Figure 54. A minimum of 2 and maximum of 40 points can
be entered for any one T curve. When you are satisfied with the values chosen, select Save Curve. Use
the Settings Explorer to browse to the 51-x element you wish to program and use the drop-down menu
under Curve to select T1, T2, T3, or T4.
Table curves can be entered regardless of the curve chosen for the protection element. However, the
table curve will not be enabled until T1, T2, T3, or T4 is selected as the curve for the protective element.
Figure 54. Inverse Overcurrent Table Curve
46 Curve
The 46 curve is a special curve designed to emulate the I
2
t withstand ratings of generators using what is
frequently referred to as the generator’s K factor. Do not confuse the 46 curve with the I2 mode. The 46
curve was designed for use with the I2 mode. However, in actuality, the 46 curve can be selected for use
with any mode of the inverse overcurrent element as well.
BE1-11t Inverse Overcurrent (51) Protection