1. Connect the test set for current injection to the appropriate IED phases.
If there is any configuration logic that is used to enable or block any of the four
available overcurrent steps, make sure that the step under test is enabled (for
example, end fault protection).
If 1 out of 3 currents are chosen for operation: Connect the injection current to
phases A and neutral.
If 2 out of 3 currents are chosen for operation: Connect the injection current into
phase A and out from phase B.
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.
1MRK 502 073-UUS A Section 13
Testing functionality by secondary injection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 189
Commissioning manual
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