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6.5 ZONE REACH TESTS
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 6–17. The value of I
pickup voltage, V
NOM
V
calculations are referenced to the leading phase-to-ground faulted voltage. When an AB fault is applied,
NOM
the current 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 6–25 and 6–26.
The nominal pickup voltage is given by
(
⁄
2 1.732
V
=
----------------------------------------------- -
NOM
cos
(
∅ Z
∅ T 180°
for
+
–
(
⁄
2 1.732
V
=
----------------------------------------------- -
NOM
cos
∅ Z
<
∅ I
<
(
∅ Z ∅ T
for
–
where: Z
= relay reach for Z1PHASE, Z2PHASE, Z3PHASE, or Z4PHASE.
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
c) SETTINGS AND CALCULATIONS
1. Record the following relay settings:
(1401), POSSEQANG = [________]
(102), Z1PRREACH = [________] (Zone 1)
(202), Z2PHREACH = [________] (Zone 2)
(302), Z3PHREACH = [________] (Zone 3)
(402), Z4PHREACH = [________] (Zone 4)
Z1PCHARANG = 90° (fixed for Zone 1)
(203), Z2PCHARANG = [________] (Zone 2)
(303), Z3PCHARANG = [________] (Zone 3)
(403), Z4PCHARANG = [________] (Zone 4)
2. Determine the test current, I
I
(Z1R) = [________] Amps rms
T
I
(Z2R) = [________] Amps rms
T
I
(Z3R) = [________] Amps rms
T
I
(Z4R) = [________] Amps rms
T
6-
16
6.5.7 ZONE 1 TO 4 PHASE-TO-PHASE REACH CALCULATIONS
is chosen according to the value of the reach of the zone. The nominal
T
, is calculated with respect to I
) Z
⋅
⋅
I
R
T
⋅
(
(
∅ I
cos
+
(
90° ∅ T
)
–
)
<
∅ I ∅ Z
<
, or
) Z
⋅
⋅
I
R
T
⋅
(
(
∅ I
cos
+
(
90° ∅ T
)
–
)
+
180°
.
, chosen for the zone.
op
, for Zone 1, Zone 2, Zone 3, and Zone 4 from Table 6–2.
T
LPS-D Line Protection System
6 FUNCTIONAL TESTS (USER SETTINGS)
and to several settings of the relay.
T
) ∅ Z
∅ T
)
30°
–
–
+
90°
(eq. 6–25)
) ∅ Z
∅ T 90°
)
30°
–
+
–
(eq. 6–26)
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