7UT51 v3
Bench Testing
16
PRIM-2330C 167
16.3.6 Testing Harmonic Restraint
Connect the relay as shown in Figure 16.8.
Figure 16.8
Differential Testing with Harmonic Restraint
For testing the harmonic restraint, it must be:
1. Parameterized as operative,
On
in Address 1610.
2. Set the Source 1, @ 60Hz to 1.2 x 87-I
trip
(as
calculated in Section 16.3.4 on page 165). To
minimize current requirements, choose a phase of
the winding that has the lowest 87-I
trip
setting.
This is typically a phase of Winding 1 (high voltage
side of the transformer). Avoid operation of 87HS
or exceeding the continuous current rating of the
7UT51.
3. Set the harmonic source to:
4. Remember to set the harmonic source to the
correct frequency (that is, 120 Hz for second
harmonic).
5. First apply only Source 1 current to verify 87
tripping.
6. Turn
Off
Source 1. Reset targets.
7. Enable both sources simultaneously. The relay
should restrain.
8. Turn
Off
both sources.
9. Slightly adjusting the Source 2 current magnitude
while the currents are off, until the minimum
Source 2 current magnitude for restraint is found.
10. Reset all targets and annunciations.
11. Complete steps 1 through 9 for the nth harmonic.
This test need only be done to one input.
Expected Results
The percent of second harmonic current required for
restraint is:
The result should be within +/- 5% of Address 1611.
When 87 tripping occurs, the operations of the
contacts, LEDs, and LCD should be consistent with
87T testing in Section 16.3.4 on page 165.
For the harmonic restraint, LEDs and contacts
programmed to operate for 87 tripping should not
operate. After current is turned off, an LCD message
may appear. For the default settings, the message
should be “
87DiffGenFlt
.”
16.4 Testing Restricted
Ground Fault Protection
(7UT513 Only)
The tests in this section will be based upon the
application shown in Figure 16.9. Adjust the following
test procedure to match the specifics of your
application as necessary.
Note:
This test can only be performed if the 7UT513
is ordered with the restricted ground-fault
protection option, 87N.
The protection is operational when configured other
than
Nonexistent
and set to
ON
.
.2
address 1611, 2nd Harmonic Res.
100
----------------------------------------------------------------------------------
× Source 1 current×
%2nd Harmonic Restraint
Source 2, 120Hz current
Source 1, 60Hz current
----------------------------------------------------------
100×=
To Next Page
Loading...
