148
Scheme communication Chapter 11
Verifying settings by secondary
injection
12 Scheme communication
12.1 Scheme communication logic for
distance protection (PSCH, 85)
Prepare the IED for verification of settings as outlined in section 1 "Overview" and section 2
"Preparing for test" in this chapter.
Check the scheme logic during the secondary injection test of the impedance or overcurrent pro-
tection functions. For details see the ordering sheets for each particular REx670 IED.
Activating the different zones verifies that the ZCS signal is issued from the intended zones. The
CS signal from the independent tripping zone must have a tSendMin minimum time.
Check the tripping function by activating the CR and CRG inputs with the overreaching zone
used to achieve the CACC signal.
It is sufficient to activate the zones with only one type of fault with the secondary injection.
12.1.1 Testing permissive underreach
Procedure
1. Activate the carrier receive (CR) signal in the IED.
2. Apply healthy normal load conditions to the IED for at least two sec-
onds.
3. Apply a fault condition within the permissive zone.
4. Check that correct trip outputs, external signals, and indications are
obtained for the actual type of fault generated.
5. Check that other zones operate according to their zone timers and
that the carrier send (CS) signal is obtained only for the zone config-
ured to generate the actual signal.
6. Deactivate the carrier receive (CR) signal in the IED.
7. Check that the trip time complies with the zone timers and that cor-
rect trip outputs, external signals, and indications are obtained for
the actual type of fault generated.
12.1.2 Testing permissive overreach
Procedure
1. Activate the carrier receive (CR) signal in the IED.
2. Apply healthy normal load conditions to the IED for at least two sec-
onds.
3. Apply a fault condition within the permissive zone.
4. Check that correct trip outputs, external signals, and indication are
obtained for the actual type of fault generated.
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