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3
3.1
3.2
170
Trip value recorder (TVR)
Trip value recorder (TVR)
Application
Use the trip value recorder to record fault and prefault phasor values of voltages and currents to
be used in detailed analysis of the severity of the fault and the phases that are involved. The re-
corded values can also be used to simulate the fault with a test set.
Design
Pre-fault and fault phasors of currents and voltages are filtered from disturbance data stored in
digital sample buffers.
When the disturbance report function is triggered, the function looks for non-periodic change in
the analog channels. Once the fault interception is found, the function calculates the pre-fault
RMS values during one period starting 1,5 period before the fault interception. The fault values
are calculated starting a few samples after the fault interception and uses samples during 1/2 - 2
periods depending on the waveform.
If no error sample is found the trigger sample is used as the start sample for the calculations. The
estimation is based on samples one period before the trigger sample. In this case the calculated
values are used both as pre-fault and fault values.
The recording can be viewed on the local HMI or via SMS.
Chapter 11
Monitoring
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