ASTM D2759-00

Standard Practice for Sampling Gas from a Transformer Under Positive Pressure

SCOPE
1.1 This practice covers the sampling of gas above the insulating liquid of a transformer. A gas sampling bottle collects the gas sample from the gas space that is at a positive pressure.  
1.2 Representative samples of gas are taken for analysis to determine their compositions.  
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-2000
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: D27 - Electrical Insulating Liquids and Gases
• Drafting Committee: D27.07 - Physical Test

Relations

• Replaced By: ASTM D2759-00(2005) - Standard Practice for Sampling Gas from a Transformer Under Positive Pressure
• Effective Date: 01-Oct-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D 2759–00
Standard Practice for
Sampling Gas from a Transformer Under Positive
Pressure
This standard is issued under the fixed designation D 2759; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope then be dried by blowing out with dry air or nitrogen, oven
baking, or be dried under vacuum.
1.1 This practice covers the sampling of gas above the
3.2 Plastic Bag—The bag should have only one opening
insulating liquid of a transformer. A gas sampling bottle
arranged to fit over one of the hose connectors on the sampling
collects the gas sample from the gas space that is at a positive
bottle. The plastic bag should have a volume, when fully
pressure.
expanded, of approximately 15 times the volume of the
1.2 Representative samples of gas are taken for analysis to
sampling bottle.
determine their compositions.
1.3 This standard does not purport to address all of the
4. Procedure
safety problems, if any, associated with its use. It is the
4.1 Before connecting the sampling bottle to the trans-
responsibility of the user of this standard to establish appro-
former, purge the outlet valve on the transformer by exhausting
priate safety and health practices and determine the applica-
a small amount of gas to remove any moisture, oil or other
bility of regulatory limitations prior to use.
contaminants.
2. Significance and Use 4.2 Attach one end of the gas sampling bottle by plastic
hose to the transformer outlet valve, and the other end of the
2.1 A gas sample from above the insulating liquid in
sampling bottle to the plastic bag, making sure that a leakproof
transformers and other electrical power apparatus can be used
connection is obtained.
to give an early indication of developing fault conditions.
4.3 Purge the sampling bottle and hose of air by first
Combustible gases are formed from the breakdown of the
opening both valves of the sampling bottle and then slightly
insulating materials under thermal and electrical stress. Exces-
opening the outlet valve on the transformer. As the gas flows
sive concentrations of combustible gases indicate the need to
through the sampling bottle, the plastic bag will expand.
take appropriate action.
4.4 When the bag has expanded to its full volume, first close
2.2 Itisimportantthatgassamplesfromequipmentbetaken
the valve adjacent to the bag; then close the valve at the other
from the gas space directly above the liquid level, and not from
endofthesamplingbottle,andfinallyclosethetransformergas
remote expansion comp
...