13-24
Testing and Troubleshooting
Date Code 20011205
SEL-311B Instruction Manual
(
)
(
)
ohms
45
.
5
RT
2
Z
45
.
5
•
25
.
0
45
.
5
•
75
.
0
RT
2
Z
m
2
Z
•
25
.
0
R
2
Z
•
75
.
0
RT
2
Z
=
+
=
+
=
The R32Q element asserts when Z2c applied is greater than Z2RT. As the
magnitude of I
A
is increased, the magnitudes of Z2c and Z2m decrease. For
magnitudes of I
A
less than 3.3 amps, R32Q asserts, given the other test quantities.
For I
A
magnitudes greater than 3.3 amps, Z2c is less than Z2RT, so R32Q deasserts.
For Z2F = 0.77
W
:
(
)
amps
4
.
23
I
ohms
77
.
0
volts
0
.
6
•
3
I
A
A
=
=
Calculate Z2m:
ohms
77
.
0
m
2
Z
A
8
.
7
V
0
.
6
m
2
Z
I
V
m
2
Z
2
2
=
=
=
Because Z2F is positive, use Equation 13.3 to calculate Z2FT.
(
)
(
)
ohms
77
.
0
FT
2
Z
77
.
0
•
25
.
0
77
.
0
•
25
.
1
FT
2
Z
m
2
Z
•
25
.
0
F
2
Z
•
25
.
1
FT
2
Z
=
-
=
-
=
The F32Q element asserts when Z2c is less than Z2FT. As the magnitude of I
A
is
increased, the magnitudes of Z2c and Z2m decrease. For magnitudes of I
A
less than
23.4 amps, F32Q should not assert, given the other test quantities. For I
A
magnitudes
greater than 23.4 amps, Z2c applied is less than Z2FT, so F32Q asserts.
Step 5.
Turn on the voltage source.
Apply V
A
= 18.0 V
Ð
180° I
A
= 0.0 A
Ð
96°.
Slowly increase the magnitude of I
A
, without varying the phase angle.
The relay R32Q element asserts, closing OUT107 when
│
I
A
│
= 0.5 amps. This
indicates that Z2c applied is greater than Z2RT, 3I
2
is greater than 50QR, and I
2
is
greater than a2
×
I
1
, where a2 is the relay setting.
Continue to increase the magnitude of I
A
. R32Q deasserts when
│
I
A
│
= 3.3 amps,
indicating that Z2c is now less than Z2RT. F32Q asserts, closing OUT106 when
│
I
A
│
= 23.4 amps, indicating that Z2c is less than Z2FT.
Verify the performance described above by calculating Z2c using Equation 13.1 and
the test quantities listed above.
Summary of Contents for SEL-311B
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