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6.3 ZONE REACH TESTS
6.3 ZONE REACH TESTS
CAUTION : The A1 contact will chatter when the unit under test is near its threshold. Do not
allow this to continue! Remove the test current. A single contact closure is enough to deter-
mine that the unit has picked up.
At the start of each test is an area to record your specific setting for the function under test.
Testing the reach of the relay requires a few organized steps:
1. Choosing a test current I
2. Calculating the voltage range in which the unit will pick up.
3. Applying the test voltage and currents in accordance with the test procedure.
Equations are given for calculating the pickup voltage for a chosen circuit magnitude and phase. If you wish to
test the complete characteristic, the ALPS-Test software can be used to generate test currents and voltage
pickups for the complete characteristic for zone elements without transformer compensation (Protection Set-
ting 1204: TRSFMRTYPE = NONE).
This section describes how to determine the test currents and voltages for Z1PHREACH, Z2PHREACH,
Z3PHREACH, and Z4PHREACH for Protection Setting 1204: TRSFMRTYPE = NONE. The same procedure is
used for each zone to determine the test values.
6
The test current, I
, is determined from Table 6-1. The value of I
T
of the zone. The nominal pickup voltage, V
relay.
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 6–6 and 6–7.
The nominal pickup voltage is given by
2
V
=
-------------- -
NOM
1.732
(
∠
∠
Z
T
for
–
–
180°
or
2
V
=
-------------- -
NOM
1.732
∠
<
I ∠
<
(
∠
for
Z
Definitions:
Z
= relay reach for Z1PHREACH, Z2PHREACH, Z3PHREACH, or Z4PHREACH
R
∠ Z = Angle of maximum reach.
I
= Test current for I
T
6-
8
for the impedance of the reach.
T
6.3.3 ZONE 1 TO 4 PHASE-TO-PHASE REACH CALCULATIONS
NOM
⋅
Z
I
⋅
R
T
⋅
(
(
∠
cos
I 30°
--------------------------------------
(
∠
)
cos
90°
T
–
)
<
I ∠
<
∠
Z
⋅
Z
I
⋅
R
T
⋅
(
(
∠
cos
I 30°
--------------------------------------
(
∠
)
cos
90°
T
–
I ∠
)
Z
180°
–
+
, chosen for the zone.
op
LPS-O Line Protection System
6 FUNCTIONAL TESTS (USER SETTINGS)
6.3.2 GENERAL CONSIDERATIONS
is chosen according to the value of the reach
T
, is calculated with respect to I
)
∠
∠
)
Z
T
90°
+
–
–
+
)
∠
∠
)
Z
T
90°
+
–
+
–
6.3.1 WARNING
and to several settings of the
T
(eq. 6–6)
(eq. 6–7)
GE Power Management
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