ADVANTAGES AND DISADVANTAGES OF THE AUTOTRANSFORMER CONNECTION TUTORIALS

ADVANTAGES AND DISADVANTAGES OF THE AUTOTRANSFORMER CONNECTION
What Are The Advantages & Disadvantages Of Auto-transformer Connection? 


Summarizing the advantages of the autotransformer connection:

• There are considerable savings in size and weight.
• There are decreased losses for a given KVA capacity.
• Using an autotransformer connection provides an opportunity for achieving lower series impedances and better regulation.

Summarizing the disadvantages of the autotransformer connection:

• The autotransformer connection is not available with certain threephase connections.
• Higher (and possibly more damaging) short-circuit currents can result from a lower series impedance.
• Short circuits can impress voltages significantly higher than operating voltages across the windings of an autotransformer.
• For the same voltage surge at the line terminals, the impressed and induced voltages are greater for an autotransformer than for a twowinding transformer.

In many instances, the advantages of the autotransformer connection outweigh its disadvantages.

For example, when very large MVA capability is required and where a Grd.Y-Grd.Y connection is suitable, an autotransformer is usually the design of choice.

Because an autotransformer cannot provide a Δ-Y connection, autotransformers are not suitable for use as generator step-up transformers.