Basler BE1-951, Instruction Manual

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BE1-951 Protection and Control 4-19
T =
A D
M - C
+ B D + K
T
N
Equation 4-2. Time OC
Characteristics for Trip
T
M
R
=
-
R D
2
1
Equation 4-3. Time OC
Characteristics for Reset
Table 4-11. Definitions for Equations 4-2 and 4-3
Parameter Description Explanation
TT Time to trip Time that the 51 function will take to time out and trip.
D Time dial setting Time dial setting for the 51 function.
M Multiple of pickup
Measured current in multiples of pickup. Timing algorithm has a
dynamic range of 0 to 40 times pickup.
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 characteristic is. 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 function is set for integrating reset.
R
Coefficient specific to
selected curve
Affects the speed of reset when integrating reset is selected.
Setting Programmable Curves
Curve coefficients are entered using the SP-CURVE (Settings Protection-programmable curve) command.
Table 4-12 lists the programmable curve settings.
Table 4-12. Programmable Time Current Characteristic Curve Coefficients
Setting Range Increment
Unit of
Measure Default
A Coefficient 0 to 600 0.0001 N/A 0.2663
B Coefficient 0 to 25 0.0001 N/A 0.0339
C Coefficient 0.0000 to 1.0000 0.0001 N/A 1.0000
N Coefficient 0.5 to 2.5 0.0001 N/A 1.2969
R Coefficient 0 to 30 0.0001 N/A 0.5000
SP-CURVE Command
Purpose: Reads or changes the user-programmable 51 curve parameters.
Syntax: SP-CURVE[=<A coefficient>,<B coefficient>,<C coefficient>,<N coefficient>,<R coefficient>]
Comments: See Table 4-12 for SP-Curve settings information.
SP-CURVE Command Example
Read the programmable 51 curve settings.
1. SP-CURVE
1,0,0,2,0
Courtesy of NationalSwitchgear.com