Basler BE1-11g, Instruction Manual

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9424200994 Rev U 107
BE1-11 g Inverse Overcurrent (51) Protection
Parameter Description Explanation
A
Coefficient specific to
selected curve
Affects the effective range of the time dial.
B
Coefficient specific to
selected curve Affects a constant term in the timing equation. Has greatest
effect on curve shape at high multiples of tap.
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 BESTCOMS Plus .
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
BESTCOMS Plus is used to set the 51 element Table Curves (T1, T2, T3, and T4). Using the Settings
Explorer within BESTCOMS Plus , open the Protection, Current, Table Curve (1, 2, 3, or 4) tree branch and
select the table curve to be modified. Refer to Figure 66. 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 66. Inverse Overcurrent Table Curve