SATEC EM920 Operation Manual - Manual (Page 26)

Chapter 2 Operating the EM920
Operating the Fast Transient Recorder
26 EM920 Power Quality and Revenue Meter
reports, and long-term harmonics survey statistics for
trouble-shooting harmonic problems throughout an electrical
network. It also records time-tagged voltage disturbances
and voltage fault events into the Power Quality event log.
All power quality triggers have programmable thresholds and
can be adjusted for a specific application.
The PQ recorder is configurable for triggering the Waveform
recorder to record fault voltage and current waveforms
before, within and after an event, and can also trigger the
Data recorder for long-duration profiling of RMS voltages and
currents while the event continues, using a variable recording
rate and variable averaging intervals.
See Configuring the EN50160 Recorders in Chapter 5 and
EN50160 Evaluation and Recording in Appendix F for more
information on configuring and operating the PQ recorder.
Operating the Fast Transient Recorder
The fast transient recorder is provided with the optional
transient add-on module. It can detect impulsive and low
frequency oscillatory transient overvoltages with peaks up to
2kV and durations from 20 microseconds.
The recorder does not require any special setup above a
conventional PQ recorder setup for transient overvoltages.
Waveform log #3 is especially dedicated for fast transient
waveforms. It automatically stores 1-cycle voltage
waveforms sampled at a rate of 1024 samples/cycle
whenever a transient overvoltage is detected.
Unlike a basic transient recorder provided with the EM920
that detects and records transient voltages between phase
conductors and a neutral terminal (in 4LN3 and 3LN3
configurations), or between two phase conductors (in line-to-
line configurations), the fast transient recorder detects
transient voltages between phase conductors and a ground
terminal and between the neutral and a ground terminal
regardless of a wiring configuration.
See the EM920 Installation Manual for the terminal location
and wiring diagrams. To help you check your voltage
connections, the EM920 provides 1-cycle phase RMS voltages
V1x through V3x, and 1-cycle neutral voltage V4x relative to
the ground terminal, that you can monitor via PAS.
Operating the Fault Recorder
The programmable Fault recorder stores time-tagged fault
events into the fault event report. It can be triggered
externally through a digital input or internally from the
embedded fault detector.
The fault detector can automatically detect different fault
categories using the meter sub-cycle measurements. Fault
triggers have programmable thresholds and hysteresis and
can be adjusted for specific substation conditions.
The Fault recorder is programmable for triggering the
Waveform recorder to record fault voltage and current
waveforms before, within and after a fault event, and can