Three-phase transformers

System

A major advantage of alternating and three-phase current compared to direct current is that it is possible to generate electrical energy economically in large power plants, transmit it at high voltage over long distances with low losses and then make it available to the consumer at a level that suits him or her. This is achieved by using transformers.

With this equipment set, a three-winding transformer consisting of three individual poles with different switching options of the primary side and variable secondary voltage is examined. The third winding (tertiary winding) is provided as a so-called triangular balancing winding for the case of an unbalanced load.

Learning objectives

• Behaviour of a three-phase transformer under short circuit, no-load and load (RLC)
• Calculation of the equivalent circuit of a transformer from measurements
• Behaviour under unbalanced load and influence of the balancing winding
• Demonstration of an autotransformer

Through measurements and calculations, the learner should understand and determine the behaviour and characteristics of a transformer.

Target groups

Pupils in vocational training in power engineering. Training in the field of power plant technology in industry. Students in general electrical engineering and power engineering. Levels up to a bachelor's degree.

Knowledge of three-phase or alternating current technology is a prerequisite.

Topics

• Behaviour during no-load operation
• Behaviour during short circuit
• Behaviour during load operation
• Behaviour under unbalanced load
• Determination of the zero impedance
• Demonstration of an autotransformer