3-6
BE1-46N Functional Description
NOTE
For the following step, any % value can be used. In this example, 50% has been chosen
only for convenience.
I
single
phase
3(I
nominal
)(I
2
pu)
I
single
phase
3(3.92)(0.5)
I
single
phase
5.88 A
I
single
phase
3(I
nominal
)(I
2
pu)
I
single
phase
3(0.784)(0.5)
I
single
phase
1.176 A
NOTE
For the following step, any % value can be used. In this example, 50% has been chosen
only for convenience.
I
2
I
A
I
B
I
C
then,
0.5 ×
I
2
0.5 ×
I
INPUT
j
0.5 × 3.92
1.96 A
I
2
I
A
I
B
I
C
then,
0.5 ×
I
2
0.5 ×
I
INPUT
j
0.5 × 0.784
0.392 A
To set the nominal current value (current being applied to the relay as derived in the calculation example),
perform the following steps.
Step 1.
Set the TAP ADJUST switch to the next higher current value (4.0 A, position E for 5 A CT or 0.80
A, position E for 1 A CT) of the desired current value (3.92 A for 5 A CT or 0.784 A for 1 A CT).
Step 2.
Set the % I
2
PICKUP thumbwheel switch to a value of 50 (0.5 pu).
Step 3.
Using equation B, solve for I
single-phase
.
5 Amp CT
1 Amp CT
Equation B is:
Step 4.
Apply the calculated I
single-phase
to one of the phase inputs of the relay (example, phase A input,
relay case terminals 8, 9) and adjust the TAP CAL control from a fully clockwise position, counter-
clockwise until the front-panel PICKUP LED is ON.
The nominal current value is now set at 3.92 amperes (for 5 A CT) or 0.784 amperes (for 1 A CT) for this
application.
Method 2, Three-Phase
If any two phases of a balanced three phase source are rotated, I
input
= I
2
because a reverse phase quantity
is being applied. The relay sees this as a 100% negative sequence condition.
To set the nominal current value (current being applied to the relay as derived in the calculation example):
Step 1.
Set the TAP ADJUST switch to the next higher current value (4.0 amperes, position E for 5 A CT
or 0.80 amperes, position E for 1 A CT) of the desired current value (3.92 amperes for 5 A CT or
0.784 amperes for 1 A CT).
Step 2.
Set the % I
2
PICKUP thumbwheel switch to a value of 50 (0.5 pu)
Step 3.
If applying A-C-B sequence,
5 Amp CT
1 Amp CT
Step 4.
Apply 1.96 amperes (for 5 A CT) or 0.392 amperes (for 1 A CT), and adjust the TAP CAL control
from a fully clockwise position, counter-clockwise until the front-panel PICKUP LED is ON.
The nominal current value is now set at 3.92 amperes (for 5 A CT) or 0.784 amperes (for 1 A CT) for this
application.
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