7-30 Maintenance and Testing Date Code 20011026
SEL-321/321-1 Instruction Manual
Because Z2F is positive, use Equation 7.4 to calculate Z2FT.
() ()
ohms77.0FT2Z
77.0•25.077.0•25.1FT2Z
m2Z•25.0F2Z•25.1FT2Z
=
−=
−=
The 32QF 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, 32QF should not assert, given the other test quantities. For I
A
magnitudes
greater than 23.4 amps, Z2c applied is less than Z2FT, so 32QF asserts.
Step 5. Turn on the voltage sources.
Apply:
°∠=
°∠=
°−∠=
°∠=
96A0.0I
120V0.67V
120V0.67V
0V0.49V
A
C
B
A
Slowly increase the magnitude of I
A
, without varying the phase angle.
The relay 32QR element asserts, closing OUT8 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
. 32QR deasserts when │I
A
│ = 3.3 amps,
indicating that Z2c is now less than Z2RT. 32QF asserts, closing OUT7 when │I
A
│
= 23.4 amps, indicating that Z2c is less than Z2FT.
Verify that the relay operated properly by calculating Z2c using Equation 7.2 and the
test quantities listed below.
For:
°∠=
°−∠=
°∠=
°∠=
120V0.67V
120V0.67V
0V0.49V
96A30.3I
C
B
A
A
°∠=°∠
=
°∠=
97.831ANG1Z1
10.1I
180V0.6V
2
2
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