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Synchronizing Two or More CMC Test Sets
5 Synchronizing Two or More CMC
Test Sets
Figure 5-1 shows a typical field application of the CMGPS synchronization unit:
Power transmission lines are usually protected by means of distance or
differential relays. Line differential relays require a signal link for comparing
currents' amplitudes or phases at both ends of the line. Distance relays are quite
often equipped with signal links in order to enable instantaneous tripping at
100 % of the protected line segment.
Here, two CMGPS synchronization units trigger two CMC test sets to start a test
at the exact same point of time. Since the GPS signal is available worldwide, the
physical distance between these test sets is thereby of no relevance ("end to
end" testing).
Figure 5-1:
Example: Testing a
power transmission
line's protection system
with two
GPS-synchronized
CMC test sets
The synchronization accuracy depends on the settings made at the Time
Trigger Configuration window of the Test Universe software. Test Universe
differentiates between standard and enhanced accuracy. See the following
chapters.
CMGPS CMGPS
Signal Signal
Relay Relay
CMC 356 CMC 3563V, 3I, Trip 3V, 3I, Trip
Antenna Antenna
Test Universe
software
Test Universe
software
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