102
Distance protection Chapter 11
Verifying settings by secondary
injection
5.3.8 Completing the test
Continue to test another function or end the test by changing the test mode setting to off.
5.4 Automatic switch onto fault logic (PSOF)
Prepare the IED for verification of settings as outlined in section 1 "Overview" and section 2
"Preparing for test" in this chapter.
The PSOF is checked using secondary injection tests together with the distance or overcurrent
protection function and with the Dead Line Detection (DLD) function which is embedded in the
PSOF function. The switch-onto-fault function is activated either by the external input BC, or
by the internal DLD function which is integrated in the FUSE function. The latter is done with
a prefault condition where the phase voltages and currents are at zero. A reverse three-phase
fault with zero impedance and a three-phase fault with an impedance corresponding to the whole
line is applied. This fault shall cause an instantaneous trip and result in a TRIP indication.
5.4.1 External activation of the PSOF function
Procedure
1. Activate the switch-onto-fault BC input.
During normal operating conditions, the BC input is de-energized.
2. Apply a three phase fault condition corresponding to a fault at ap-
proximately 45% of the line or with an impedance at 50% of used
zone setting and current greater than 30% of I
r
.
3. Check that the correct trip outputs, external signals and indication
are obtained.
5.4.2 Automatic initiation of PSOF
Procedure
1. Deactivate the switch-onto-fault BC input.
2. Set current and voltage inputs to 0 for at least 1 second.
3. Apply a three phase fault condition corresponding to a fault at ap-
proximately 45% of the line or with an impedance at 50% of used
zone setting and current greater than 30% of I
r
.
4. Check that the correct trip outputs, external signals and indication
are obtained.
5.4.3 Completing the test
Continue to test another function or end the test by changing the test mode setting to off. Restore
connections and settings to their original values, if they were changed for test purposes.
To Next Page
Loading...
