POWER TRANSFORMERS - PART 7: LOADING GUIDE FOR MINERAL-OIL-IMMERSED POWER TRANSFORMERS
International Electrotechnical Committee
FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and abbreviations
5 Effect of loading beyond nameplate rating
6 Relative ageing rate and transformer insulation life
7 Limitations
8 Determination of temperatures
9 Influence of tap-changers
Annex A (informative) - Insulation life expectancy and relative
ageing rate considering oxygen and water effect
Annex B (informative) - Core temperature
Annex C (informative) - Specification of loading beyond rated
power
Annex D (informative) - Description of Q, S and H factors
Annex E (informative) - Calculation of winding and oil time
constant
Annex F (informative) - Thermal model parameters
Annex G (informative) - Oil and winding exponents
Annex H (informative) - Practical example of the exponential
equations method
Annex I (informative) - Application of the difference equation
solution method
Annex J (informative) - Flowchart, based on the example in
Annex H
Annex K (informative) - Example of calculating and presenting
overload data
Annex L (informative) - Geomagnetic induced currents
Annex M (informative) - Alternative oils
Bibliography
Defines the effect of operation under various ambient temperatures and load conditions on transformer life.
| Document Type | Standard |
| Status | Current |
| Publisher | International Electrotechnical Committee |
| Committee | TC 14 |
