Thermal Overload Protection, One Time Constant (Pttr, 26) - ABB REL670 Installation And Commissioning Manual

6.6
6.6.1
Current protection

Thermal overload protection, one time constant (PTTR, 26)

Prepare the IED for verification of settings as outlined in
"Preparing for test" in this chapter.
Check that the input logical signal BLOCK is logical zero and that on the local HMI, the logical
signal TRIP, START and ALARM are equal to logical 0.
Measuring the operate and time limit of set values
Testing the protection without external temperature compensation (NonComp)
Procedure
1. Quickly set the measured current (fault current) in one phase to
about 300% of IRef (to minimise the trip time), and switch the current
off.
2. Reset the thermal memory under menu tree:
Reset\Reset temperature\ThermalOverload1TimeConst(PTTR,26)\THLn
3. Switch the fault current on and take note of the temperature:
Test\Current protection\ThermOverLoad1TimeConst(PTTR,26)\THLn\TEMP
4. Check the Alarm time limit AlarmTemp during injection.
Measure the signal ALARM until it appears on the corresponding binary
output or on the local HMI.
5. Compare the measured temperature with the setting.
6. Measure the THL protection trip time.
Use the TRIP signal from the configured binary output to stop the timer.
7. Take the "TEMP" readings.
Compare with the setting of TripTemp.
8. Activate the BLOCK binary input.
The signals ALARM, START and TRIP should disappear.
9. Reset the BLOCK binary input.
10. Check the reset limit (TdReset).
Measure the signal START until it disappears on the corresponding bina-
ry output or on the local HMI, take the "TEMP" readings and compare
with the setting of ReclTemp.
11. Compare the measured trip time with the setting according to the
formula.
12. Reset the thermal memory.
Chapter 11
Verifying settings by secondary
section 1 "Overview" and
injection
section 2
107