IEEE DRAFT C57.104 : D11D 2004

Introduction
1. Overview
   1.1 Scope
   1.2 Limitations
2. References
3. Definitions
4. General decomposition theory
   4.1 Cellulose decomposition
   4.2 Mineral oil decomposition
5. Combustible gas generation in equipment
   5.1 Thermal fault
   5.2 Thermal faults involving cellulose
   5.3 Electrical faults
   5.4 Sampling and laboratory procedures
   5.5 Variability and precision of analysis
6. Detection and operating guidelines
   6.1 Detection procedure for transformers in Type 1 category
   6.2 Detection procedure for Type 2 transformers
7. Diagnosis of transformer faults
   7.1 Analysis in the caution surveillance range
   7.2 Diagnosis in the warning surveillance range
   7.3 Diagnosis of cellulose decomposition
8. Trend and graphical analysis
   8.1 Construction of a 3 D graph
9. Detection and analysis of gases in gas space, relay or other
   fixed or portable devices
Annex A (Normative) TCG detection and operating procedure
Annex B (Normative) TCG diagnosis of fault type

Applies to operating mineral oil immersed transformers that are newly energized and have no previous combustible gas history; and to operating mineral oil immersed transformers that have been operating long enough to develop a combustible gas database.