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6.5 ZONE REACH TESTS
1.
Setting:
Z4DISTANCE
(401) Z4PHASE = NO
(405) Z4GRND = YES
(406) Z4GRDREACH = [_________] ohms,
V
= [_________] V,
NOM 4
I
= [_________] A,
T
øI
= [_________]°,
4
2.
Connect the relay as shown in Figure 4–3: PHASE TO GROUND TEST CONNECTIONS on page 4–12 for the appro-
priate phase under test.
3.
Set the relay to the Zone 4 ground test mode for the appropriate phase under test. The LUI displays, for instance:
ZONE 4 AG ON
Set the voltage inputs as follows: VA: 67 V rms ∠0°, VB: 67 V rms ∠–120°, VC: 67 V rms ∠–240°.
4.
5.
Set the fault current, I
Set the fault current to I
6.
tact closes when the voltage is within 7% of V
7.
Reduce the fault current to zero.
8.
Return Zone 4 phase, Z4PHASE, to your specific setting.
This section describes how to determine the test currents and voltages for Z1PHASE, Z2PHASE, Z3PHASE, and
Z4PHASE. The same procedure is used for each zone to determine the test values.
The test current, IT, is determined from Table 6–2: TEST CURRENT RANGES FOR PHASE-TO-PHASE REACH on page
6–15. The value of I
is chosen according to the value of the reach of the zone. The nominal pickup voltage, V
T
6
culated with respect to I
V
calculations are referenced to the leading phase-to-ground faulted voltage. When an AB fault is applied, the current
NOM
angle is with respect to the phase angle of VA, not the phase-to-phase voltage. That is why the 1.732 (square root of three)
factor and the added angle of 30° are included in Equations 25 and 26.
The nominal pickup voltage is given by
V
=
NOM
(
∅ Z
∅ T 180°
for
+
–
V
=
NOM
∅ Z
<
∅ I
<
(
∅ Z ∅ T
for
–
where: Z
= relay reach for Z1P, Z2P, Z3P, or Z4P.
R
øZ = Angle of maximum reach.
I
= Test current for I
T
øT = Characteristic timer of the zone.
øI = Test current angle with respect to the faulted phase
POSSEQANG = Positive sequence angle of maximum reach.
6-14
, phase angle to øI = [________]°, lagging.
op
= [________] amps rms. Reduce the voltage of the faulted phase and check that the A1 con-
T
NOM
and to several settings of the relay.
T
(
⁄
) Z
⋅
⋅
2 1.732
I
R
T
⋅
(
(
∅ I
cos
30°
----------------------------------------------- -
+
(
90° ∅ T
)
cos
–
)
<
∅ I
<
∅ Z
, or
(
⁄
) Z
⋅
⋅
2 1.732
I
R
T
⋅
(
(
∅ I
cos
30°
----------------------------------------------- -
+
(
90° ∅ T
)
cos
–
)
.
+
180°
, chosen for the zone.
op
ALPS Advanced Line Protection System
6 FUNCTIONAL TESTS (USER SETTINGS)
6.5.6 T15 – ZONE 4 GROUND REACH, M4G GROUND FAULTS
.
6.5.7 ZONE 1 TO 4 PHASE-PHASE REACH CALCULATIONS
) ∅ Z
∅ T
)
90°
(eq. 6–25)
–
–
+
) ∅ Z
∅ T 90°
)
(eq. 6–26)
–
+
–
, is cal-
NOM
GE Power Management
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