IEEE C57.139-2015 pdf free

IEEE C57.139-2015 pdf free.IEEE Guide for Dissolved Gas Analysis in Transformer Load Tap Changers.
Only suitably trained personnel following the ASTM D923 procedure should perform oil DGA sampling.’ The measurement of gas concentrations should be performed by an analytical laboratory according to the methods detined in ASTM D36 12, or by properly trained personnel using a portable instrument, or by means of an on-line monitoring device (see Soundarrajan [B9]).2
A properly trained and experienced person should perform the interpretation of DGA data. Computer assistance including utilization of spreadsheets, databases, analytical software, graphical methods (e.g., Duval triangle), maintenance management systems, etc., is useful. Additional information about the LTC and the transformer on which it is mounted, including operation, maintenance, test, and environmental history, may be needed for a detailed interpretation.
For various reasons, some of which are explained in this guide, DGA results can sometimes be false or misleading, and sometimes DGA can fail to identify an actual fault that may be present. As with any diagnostic tool, care must be used when analyzing DGA results. Unexplained variations or changes in the gas concentrations can lead to inaccurate conclusions. Results should be confirmed by additional DGA testing. Diagnostic and repair decisions should not be made based on DGA results only, particularly not on a single DGA sample. In addition, other tests and consultation with experts should be employed where possible before inspection and/or repairs are performed on the equipment. [.ocal operating conditions, requirements, and safety issues should be considered.
1.4 Safety warning
The following safety warning applies only to transformer LTCs to be tested in the field, not to factory testing. Refer to factory test codes for safety warnings for these situations.
The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies.IEEE C57.139 pdf free download.