Why tertiary winding is used in autotransformer?

Advantages of Using Tertiary Winding in Transformer It reduces the unbalancing in the primary due to unbalancing in three phase load. As the tertiary winding is connected in delta formation in 3 winding transformer, it assists in limitation of fault current in the event of a short circuit from line to neutral.

What is a 3 phase autotransformer?

Introduction 3 Phase Auto Transformers. The three-phase auto-transformer has a single coil that acts both as the primary and secondary coil. They are used for starting induction motors, in audio systems, in power transmission and distribution, and even in railways.

In which of the transformer the tertiary winding is used?

In which transformer, the tertiary winding is used? When tertiary winding is used in a transformer, then that is called three winding transformer. It is exclusively used in high voltage transformer windings which are connected in star.

What is tertiary winding in a three phase transformer?

A “Tertiary” is a third winding added to a two winding transformer. Also called “Stabilizing” winding – stabilizes neutral point voltage. Stabilizing winding also helps in reduction of third-harmonic voltages in the line, thus reducing harmonic related issues, e.g. telephonic interference or heating.

Why is tertiary winding used in autotransformer connection?

If we use normal transformer the size of transformer will be very high which leads to heavy weight, more copper and high cost. The tertiary winding used in Autotransformer balances single phase unbalanced loads connected to secondary and it does not pass on these unbalanced currents to Primary side.

Why is autotransformer connection not available with 3 phase connection?

The autotransformer connection is not available with certain three-phase 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.

How are autotransformers used in bulk power transmission?

It is used quite extensively in bulk power transmission systems because of its ability to multiply the effective KVA capacity of a transformer. Autotransformers are also used on radial distribution feeder circuits as voltage regulators. The connection is shown in Figure 1 below.

Can a differential relay be used for auto transformer protection?

Normal transformer Differential protection relays and accessories can be used for Auto transformer protection also.