OCB Breaker Oil Test Report by STEC.pdf

This document contains laboratory test reports and oil analysis data from Weidmann-ACTI Inc. for transformer oil samples collected from the South Texas Electric Cooperative. The reports document ASTM D-3612 analysis of mineral oil used in OCB (oil-cooled) transformers with PPM (parts per million) reporting units.

The three test reports (pages 1-3) cover samples from OCB Tank 1, OCB Tank 2, and OCB Tank 3, all dated June 25, 2007, with sample analysis dates of December 2, 2005, and order number 187061. Key measurements across all samples include moisture content in oil (ranging from 35-36 ppm), interfacial tension (ranging from 28.7-29.8 dynes/cm), acid number (0.025-0.032 mg KOHg), color number (L1.5), dielectric breakdown (36-50 kV), and oxidation inhibitor levels. All samples showed clear visual examination results with no water visible. The diagnostics section notes that color number accuracy is acceptable for an interval of 2.0 mm, and visual acceptance applies for intervals of 2.0 mm or less. A fourth document (page 4) is a Standard Oil Analysis name plate data sheet from APTUS (a Westinghouse Company) dated April 6, 1992, documenting analysis of mineral oil from an OCB substation transformer (Serial Number 25960, Unit Number OCB Tank #2) owned by Inter'l Boundary & Water Commission in Del Rio, Texas. Test results for that sample showed dielectric strength of 45 kV, acid number of 0.009, IFT of 26.6 dynes/cm, color of 1.0, specific gravity of 0.880, no free water visible, and clear marginal visual classification.