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GEK-90636
The defective circuit may be identified by fo1lowin the procedures outlined in the
following paragraphs. The tests are based on using line frequency as the input and on
a set of known settings.
Begin by setting the relay.
TABLE VIII
SFF
Line Fre uency plus
Mode
Rate of Under
Time
Model
Fl
F2
F3
F4
Change Voltage Delay
201
0.1
Under
50%
0.1
202
0.2
0.1
Under
Out
50%
0.1
204
0.4
0.3
0.2
0.1
Under
Out
50%
0.1
Refer to figures 17 through 22 for views of the relay with and without a nameplate.
The board locations are identified by letters
Ofl
the right side of the cradle. These
letters and the part number of the printed circuit assembly for each location are given
on the internal connections diagrams in figures 10, 11 and 12.
The block diagrams in figures 14, 15 and 16 give voltages and waveforms to be found
at selected points in the relay. rllhe points are the connector pin numbers on the
extender board. The failure of the signal to meet the levels shown on the diagram
indicates a failure in that module.
The signals should measured with high input impedance instruments to avoid
loading the circuits. Remember the regulated DC is not isolated.
A logic low is a signal with an amplitude of between zero and 20% of the regulated DC
voltage, nominally this is 0 to 2.4 volts. A logic high is defined as a signal whose
amplitude is between 80 and 100 percent of the regulated DC voltage, nominally this
is 9.6 to 12 volts.
SKRVICING
CAUTION: REMOVE ALL power from relay before removing or inserting
any of the printed circuit boards or output relays. Failure to observe this
caution may result in damage to and/or misoperation of the relay.
When replacing a module check the part number and location as shown on the
internal connections diagrams in figures 10, 11 and 12 before inserting the module.
Perform the acceptance tests before returning the relay to service.
PER1O1)IC CJ-1ECI{S ANI) ROUTINE MAINTENANCE
Considering the vital role of protective relays in the operation of a power system it
is important that a periodic test program be followed. It is recognized that the
interval between periodic checks will vary depending upon environment, type of
relay, and the users experience with periodic testing. Until the user has accumulated
enough experience to select the test interval best suited to their individual
19
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