Sediment in insulating oil may deposit on transformer parts and interfere with heat transfer and may choke oil ducts; thus hindering oil circulation and heat dissipation. Inorganic sediment usually indicates contamination of some type and organic sediment indicates either deterioration of the oil or contamination.

Soluble sludge indicates deterioration of the oil, presence of contaminants, or both. It serves as a warning that formation of sediment may be imminent.

The determination of sediment and soluble sludge in a used insulating oil assists in deciding whether the oil may continue to be used in its existing condition or should be replaced, reclaimed, or reconditioned.

1. Scope

1.1 This test method covers the determination of sediment and soluble sludge in service-aged insulating oils of petroleum origin. Also, provision is made for determining organic and inorganic content of the sediment. The method is intended primarily for oils of comparatively low viscosity; for example 5.7 to 13.0 cSt (mm²/s) at 40°C (104°F). Suitability for high viscosity oils have not been determined.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D923 Practices for Sampling Electrical Insulating Liquids

D2440 Test Method for Oxidation Stability of Mineral Insulating Oil

Keywords

insulating oils; oils; sediments; sludge; soluble-sludge; Contamination--insulation materials/applications; Electrical insulating oils; Electrical insulating petroleum products; Inorganic contaminants; Organic matter content; Sediment sampling; Sludge sampling; Transformer oils;

ICS Code

ICS Number Code 29.040.10 (Insulating oils)

Citing ASTM Standards

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