6.3.3.1
Verifying the settings
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).
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.
Set the injected polarizing voltage slightly 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 55° if forward directional function is selected.
If
1 out of 3
currents for operation is chosen: 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 235° (equal to 55° + 180°).
4.
Increase the injected current and note the operate value of the tested step of the
function.
5.
Decrease the current slowly and note the reset value.
6.
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).
7.
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.
8.
Block higher set stages when testing lower set stages by following the procedure
described below.
9.
Connect a trip output contact to a timer.
10. Set the injected current to 200% of the operate level of the tested stage, switch on the
current and check the time delay.
For inverse time curves, check the operate time at a current equal to 110% of the
operate current for
txMin
.
11. Check that all trip and pickup contacts operate according to the configuration (signal
matrixes)
12. Reverse the direction of the injected current and check that the protection does not
operate.
13. Repeat the above described tests for the higher set stages.
14. Finally check that pickup and trip information is stored in the event menu.
Section 6
1MRK 505 293-UUS A
Testing functionality
48
Commissioning manual
