Determination Analysis of Energy Conservation Standards for Distribution Transformers

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv EXECUTIVES UMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . xvii . l.INTRODUCTION .. .:. .................................. l-l 1.1 BACKGROUND .................................... l-l 1.2 MARKETTRENDS ..................................... l-2 1.3 STUDYAPPROACH ................................. l-3 1.4 SCOPEANDCONTENT ............................... l-4 REFERENCES ........................................ l-5 . 2. CHARACTERIZATION OF DISTRIBUTION TRANSFORMERS AND THEIRLOSSES ..................................... i ... 2-l 2.1 OVERVIEW ...................................... 2-l 2.1.1 Principles of Transformer Operation ...................... 2-2 2.1.2 Major Transformer Loss Mechanisms: No-Load and Load Losses ...... 2-3 2.1.3 Characteristics of Liquidand Dry-Type Transformers ............ 2-6 2.2 TRANSFORMEREVALUATIONANDLOSS REDUCTIONMETHODS ..... 2-8 2.3 TRANSFORMER LOADING PRACTICES ..................... 2-10 REFERENCES ....................................... 2-12 NOTES ............................................ 2-12 3. DISTRIBUTION TRANSFORMER MARKET ...................... 3-l 3.1 MARKETTRENDSANDFORECASTS ........................ 3-l 3.2 CATEGORIZATIONBY SIZE ............................ 3-3 3.2.1 Distribution Transformers in the lO-kVA to 2.5~MVA Range ......... 3-4 3.2.2 Distribution Transformers <lO kVA ...................... 3-5 3.3 MARKETSTRUCTURE ............................... 3-5 3.4 PURCHASING PRACTICES ............................. 3-7 3.4.1 First Cost .................................... 3-7 3.4.2 Total Life-Cycle Owning Cost .......................... 3-8 3.4.3 Band of Equivalence .............................. 3-9 3.4.4 Oversizing. ................................... 3-9 3.4.5 Choice of Winding Material (Aluminum vs Copper) ............. 3-9