COMTRADE and power-quality guides

Written for protection and power-quality engineers who have a fault record in front of them and a question about it. Each guide says what the standard says, what a record can and cannot show, and how SagSwell reports it.

• How to open COMTRADE files (.cfg, .dat, .cff)

  Open a COMTRADE fault record from a relay, fault recorder or power-quality meter in a browser: which files you need, what each one holds, and what to do when a record will not open.

• The COMTRADE file format explained (IEEE C37.111)

  What is inside the .cfg, .dat, .hdr, .inf and .cff files of IEEE C37.111: channel definitions, scaling, sample rates, time stamps, and the differences between the 1991, 1999 and 2013 revisions.

• The COMTRADE .cfg file, line by line (with an annotated example)

  A real COMTRADE configuration file taken apart one line at a time: station and revision, channel counts, every field of an analog and a status channel, scaling with a and b, primary and secondary ratios, sampling rates, time stamps, file type and time multiplier.

• Voltage sags, swells and interruptions: the IEEE 1159 categories

  How IEEE 1159 names short-duration voltage variations by magnitude and duration, how a sag is measured from a waveform record, and how SagSwell reports one.

• The ITIC (CBEMA) curve and SEMI F47, point by point

  The voltage-tolerance envelopes of the ITIC (CBEMA) curve and SEMI F47 with every corner point, how an event is placed on them, and what a point outside the envelope does and does not mean.

• Harmonics and THD from a fault record: what IEEE 519 does and does not tell you

  How THD is calculated from a COMTRADE record, the IEEE 519 voltage-distortion limits by bus voltage, and why a record a few seconds long is a snapshot rather than an IEEE 519 assessment.

Looking for the tool itself? SagSwell, the online COMTRADE viewer.