This course explains complex power transformer ratings in simple language. The course covers key transformer inputs, ambient temperature load cycle, top oil hot spot, % loss of life and other key parameters from IEEE C57.91 that allows utilities to perform normal/emergency and/or short and long term ratings. You will learn critical technical knowledge, such as the impact of pre-loading condition, load factor, cooling etc. on transformer ratings as well as consequences of operating a transformer above its capacity/design temperatures. Finally, you’ll see how various parameters affect the transformer rating, particularly the maximum hot spot temperature by reviewing screenshots from a commercially available transformer rating software program. Although the transformer rating process is complex, the information in this course is presented such that it can be understood by any engineer who completed an undergraduate electrical circuits course in college.\ In Power Transformer Ratings' Calculation and Analysis - IEEE C57.91-1995, you'll learn ...

• Types of transformers and their purpose
• The relationship between voltage increase (or decrease) and the transformer turn ratio
• How transformers are protected, insulated, cooled and rated
• How various parameters affect the transformer rating, particularly the maximum hot spot temperature.

Learning Objectives:

• The purpose for transformers
• Transformer types
• The relationship between voltage and turn ratio
• How transformers regulate voltage
• Transformer protection schemes
• Transformer rating categories
• How to calculate transformer service life per IEEE C57.91-1995
• Transformer insulation systems
• Oil-cooled vs. air-cooled transformers
• The importance of the 24-hour temperature cycle and 24-hour load cycle<