Four Step Residual Overcurrent Function - ABB REL670 Installation And Commissioning Manual

6.5
106
Current protection
Procedure
1. Connect the test set for single current injection to the appropriate
IED terminals.
Connect the injection current to terminals L1 and neutral, or to terminals
N and neutral.
2. Set the injected polarizing voltage slightly larger than the set mini-
mum polarizing voltage (default 5 % of Ur) and set the injection cur-
rent to lag the voltage by an angle equal to the set reference
characteristic angle ( AngleRCA ) if the forward directional function is
selected.
If reverse directional function is selected, set the injection current to lag
the polarizing voltage by an angle equal to RCA+ 180 ° .
3. Increase the injected current and note the value at which the studied
step of the function operates.
4. Decrease the current slowly and note the reset value.
5. If the test has been performed by injection of current in phase L1, re-
peat the test when injecting current into terminals L2 and L3 with a
polarizing voltage connected to terminals L2 respectively L3.
6. Block higher set stages when testing lower set stages according to
the instructions that follow.
7. Connect a trip output contact to a timer.
8. 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 tmin.
9. Check that all trip and start contacts operate according to the con-
figuration (signal matrixes)
10. Reverse the direction of the injected current and check that the pro-
tection does not operate.
11. Check that the protection does not operate when the polarizing volt-
age is zero.
12. Repeat the above-described tests for the higher set stages.
13. Finally, check that start and trip information is stored in the event
menu.

Four step residual overcurrent function.

1. In principle this is done as described above but without applying any
polarizing voltage.
Chapter 11
Verifying settings by secondary
injection