Testing Delta Blocking Scheme; Checking Of Unblocking Logic - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.11.1.4
11.11.1.5
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
1. Deactivate the receive (CR) signal of the IED.
2. Apply healthy normal load conditions to the IED for at least two seconds.
3. Apply a fault condition within the forward directed zone used for scheme
communication tripping.
4. Check that correct trip outputs and external signals are obtained for the type
of fault generated and that the operate time complies with the tCoord timer
(plus relay measuring time).
5. Check that the other zones operate according to their zone times and that a
send (CS) signal is only obtained for the reverse zone.
6. Activate the IED receive (CR) signal.
7. Apply a fault condition in the forward directed zone used for scheme
communication tripping.
8. Check that the no trip from scheme communication occurs.
9. Check that the trip time from the forward directed zone used for scheme
communication tripping complies with the zone timer and that correct trip
outputs, external signals, and indications are obtained for the actual type of
fault generated.

Testing delta blocking scheme

1. Deactivate the receive (CR) signal of the IED.
2. Apply healthy normal load conditions to the IED for at least two seconds.
3. Apply a fault condition within the forward directed zone used for scheme
communication tripping.
4. Check that correct trip outputs and external signals are obtained for the type
of fault generated and that the operate time complies with the tCoord timer
(plus relay measuring time).
5. Check that the other zones operate according to their zone times and that a
send (CS) signal is only obtained for the reverse zone.
6. Check that for a forward fault, carrier send (CS) signal is first obtained from
the delta based fault inception detection (as it is not directional) , and
immediately inhibited by the forward zone.
7. Activate the IED receive (CR) signal.
8. Apply a fault condition in the forward directed zone used for scheme
communication tripping.
9. Check that the no trip from scheme communication occurs.
10. Check that the trip time from the forward directed zone used for scheme
communication tripping complies with the zone timer and that correct trip
outputs, external signals, and indications are obtained for the actual type of
fault generated.

Checking of unblocking logic

Check the unblocking function (if the function is required) when checking the
communication scheme.
Section 11
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