ABB RET670 Commissioning Manual page 185

1MRK 504 165-UUS -
Transformer protection RET670 2.2 ANSI
Commissioning manual
If 3 out of 3 currents are chosen for operation: Connect the symmetrical three-phase
injection current into phases A, B and C.
2. Connect the test set for the appropriate three-phase voltage injection to the IED
phases A, B and C. The protection shall be fed with a symmetrical three-phase
voltage.
3. Block higher set stages when testing lower set stages by following the procedure
described below:
3.1. Set the injected polarizing voltage larger than the set minimum polarizing
voltage (default is 5% of VBase) and set the injection current to lag the
appropriate voltage by an angle of about 80° if forward directional function is
selected.
If 1 out of 3 currents are chosen for operation: The voltage angle of phase A is
the reference.
If 2 out of 3 currents are chosen for operation: The phase angle of the phase-
to-phase voltage AB is the reference for APhase.
If 3 out of 3 currents are chosen for operation: The voltage angle of phase A is
the reference.
If reverse directional function is selected, set the injection current to lag the
polarizing voltage by an angle equal to 260° (equal to 80° + 180°).
3.2. Increase the injected current, note the trip value of the tested step of the
function and compare it to the set value.
3.3. Decrease the current slowly, note the reset value and compare it to the reset
ratio 95%.
4. If the test has been performed by injection of current in phase A, repeat the test,
injecting current into phases B and C with polarizing voltage connected to phases B,
respectively C (1 out of 3 currents for operation).
5. If the test has been performed by injection of current in phases AB, repeat the test,
injecting current into phases BC and CA with the appropriate phase angle of injected
currents.
6. Connect a trip output contact to a timer.
7. Set the injected current to 200% of the trip level of the tested stage, switch on the
current and check the time delay.
For inverse time curves, check the trip time at a current equal to 110% of the trip
current for txMin.
8. Check that all trip and pickup contacts trip according to the configuration (signal
matrixes).
9. Reverse the direction of the injected current and check that the protection does not
trip.
10. If 2 out of 3 or 3 out of 3 currents are chosen for operation: Check that the function
will not trip with current in one phase only.
11. Repeat the above described tests for the higher set stages.
12. Check that pickup and trip information is stored in the event menu .
Testing functionality by secondary injection
Section 11
179