Autocalibration - OPT100

OPT100 User Guide
Document code
M211858EN
Revision
AA
Language
English
Product
OPT100
Document type
User guide

The autocalibration feature of the DGA monitor improves measurement performance by adapting the measurement to the individual oil conditions of the transformer. Autocalibration is implemented as special type of measurement cycles that vary the parameters of the vacuum gas extraction. The process typically completes in two days, but may take longer if ambient temperature is high. After autocalibration is completed, the measurement algorithm is adjusted according to the analysis results, and normal measurement cycles are automatically resumed.

DGA monitor makes use of autocalibration in the following ways:

Table 1. Types of autocalibration
Autocalibration type Description Notes
Initial autocalibration Initial autocalibration runs automatically after a DGA monitor has been initialized and measurement started. Initial autocalibration cannot be skipped, and it must complete successfully for DGA monitor to operate normally. Measurement results generated during the initial autocalibration may not be accurate. Gas level alerts are not indicated during initial autocalibration via any means, including relays.
Secondary initial autocalibration Two days after the initial autocalibration, a secondary initial autocalibration runs in verification of the first one. Normal measurement performance is already achieved after finishing the first initial autocalibration.
Manually started autocalibration One-time autocalibration that is started manually by the Admin user.

Recommended after:

  • Transformer degassing or oil change
  • DGA monitor software update
  • DGA monitor repair if components of measurement electronics have been replaced
Automatically started autocalibration DGA monitor performs autocalibration when needed and when environmental conditions are suitable.
  • For devices using ester liquid, automatic autocalibration is not performed when the ambient temperature is too cold. The approximate limit is 0 °C (32 °F).

Ensures the long term accuracy of measurement results as measurement conditions change and transformer oil ages. Typical interval between autocalibrations is one month.

If automatically started autocalibration is not desired, the feature can be disabled by the administrator user.

Measurement results generated during autocalibration cycles are indicated with a light blue background in measurement graphs. They are also marked in the CSV data that is exported using the Download Data function.