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14
14.1
14.1.1
96
Thermal overload protection (THOL)
Thermal overload protection (THOL)
Prepare the terminal for verification of settings as outlined in section "Preparing for
test" in this chapter.
Check that the input logical signal THOL-BLOCK is logical zero and note on the local
HMI that the logical signal THOL-TRIP, THOL-START and THOL-ALARM are
equal to the logical 0. Logical signals for thermal overload protection are available un-
der menu tree:
ServiceReport/Functions/ThermOverLoad/FuncOutputs
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 I1b (to minimise the trip time), and switch off
the current with the switch.
2.
Reset the thermal memory under menu tree:
Test/ThermReset
3.
Switch on the fault current and read the presented tempera-
ture:
ServiceReport/Functions/ThermOverload/ThermOverload/T Line
4.
Check the Alarm limit (TAlarm) during injection.
Measure the signal THOL-ALARM until it appears on the corre-
sponding binary output or on the local HMI unit.
5.
Compare the measured temperature with the setting.
6.
Measure the trip time of the THOL protection.
Use the THOL-TRIP signal from the configured binary output to
stop the timer.
7.
Take the "T Line" readings.
Compare with the setting of TTrip.
Chapter 11
Verifying settings by secondary
injection
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