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CHAPTER 7: TESTING
7.3.4
Voltage Phase Reversal Test
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
1
2
-- - I
(
a
I
+
+
I
a
b
3
2
--- -
------------------------------------------ -
=
I
1
1
-- - I
(
aI
+
+
a
b
3
Given the values in the figure above, we have:
I
780 0°
∠
(
1 120°
∠
+
2
--- -
--------------------------------------------------------------------------------------------------------------------------------------------------------------- -
=
I
780 0°
∠
(
1 120°
∠
1
+
780 0°
∠
1000 127°
+
-------------------------------------------------------------------------------------------- -
=
780 0°
∠
1000 7°
+
780 601.8
j798.6 601.8
–
+
-------------------------------------------------------------------------------------------- -
=
780
992.5
j121.9
+
+
If FLA = 1000, then:
I
=
avg
and since
I
926.7 A 1000
=
avg
469 Unbalance
The 469 specification for unbalance accuracy is ±2%. Perform the steps below to verify
accuracy.
Alter the following settings:
S2 SYSTEM SETUP
CURRENT SENSING
S2 SYSTEM SETUP
CURRENT SENSING
Inject the values shown in the table below.
Verify accuracy of the measured values.
View the measured values in:
A2 METERING DATA
INJECTED CURRENT
1 A UNIT
5 A UNIT
Ia = 0.78 A ∠0°
Ia = 3.9 A ∠0°
Ib = 1 A ∠113°
Ib = 5 A ∠113°
Ic = 1 A ∠247°
Ic = 5 A ∠247°
Ia = 1.56 A ∠0°
Ia = 7.8 A ∠0°
Ib = 2 A ∠247°
Ib = 10 A ∠247°
Ic = 2 A ∠113°
Ic = 10 A ∠113°
Ia = 0.39 A ∠0°
Ia = 1.95 A ∠0°
Ib = 0.5 A ∠247°
Ib = 2.5 A ∠247°
Ic = 0.5 A ∠113°
Ic = 2.5 A ∠113°
The 469 can detect voltage phase rotation and protect against phase reversal. To test the
phase reversal element, perform the following steps:
Alter the following settings:
aI
)
c
where a
1 120°
∠
=
2
a
I
)
c
2
)
(
1000
∠
113°
)
(
1 120°
–
+
) 1000
(
∠
113°
)
(
1 120°
–
+
∠
1000 233°
∠
+
∠
1000 353°
∠
+
j798.6
–
–
–
---------------- -
=
992.5 j121.9
+
–
780
1000
1000
+
+
---------------------------------------------- - A
=
3
<
FLA
, the 469 unbalance is:
=
926.7
×
-------------
×
0.1532
100%
=
–
1000
PHASE CT PRIMARY:
MOTOR FULL LOAD AMPS FLA:
CURRENT METERING
EXPECTED
UNBALANCE
LEVEL
14%
15%
7%
0.5
j0.886
=
–
+
∠
) 1000 113°
(
∠
)
2
∠
)
(
1000 113°
∠
)
423.6
0.1532
=
2765
926.7 A
14.2%
=
"1000 A"
"1000 A"
MEASURED
UNBALANCE
LEVEL
(EQ 7.2)
(EQ 7.3)
(EQ 7.4)
(EQ 7.5)
7–13
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