AC MACHINES-1 (66761) Theory
Completion requirements
7. Realize the construction and Principle of operation of three phase transformer.
7.2. List various methods of connection of 3-phase transformer and their applications.
Three-Phase Transformer Connections
The three phase transformer consists three transformers either separate or combined with one core. The primary and secondary of the transformer can be independently connected either in star or delta. There are four possible connections for a 3-phase transformer bank.
- Δ – Δ (Delta – Delta) Connection
- Υ – Υ (Star – Star) Connection
- Δ – Υ (Delta – Star) Connection
- Υ – Δ (Star – Delta ) Connection
The choice of connection of three phase transformer depends on the various factors likes the availability of a neutral connection for grounding protection or load connections, insulation to ground and voltage stress, availability of a path for the flow of third harmonics, etc. The various types of connections are explained below in details.