Star connection:
1. Three windings are connected together at their endpoints to form a neutral point.
2. Both the high and low voltage sides are represented by the letter "Y".
3. Mainly used in low voltage and high current application scenarios.
Triangle connection:
1. Connect the two ends of the winding in sequence to form a closed circuit.
2. There is no neutral point, so the neutral wire cannot be drawn out.
3. Mainly used in high current and low voltage application scenarios.
Serrated (tortuous) connection:
1. Each phase is composed of two equal windings, which are connected together at the endpoints.
2. Represent with the letter "Z".
3. Suitable for situations where there may be load imbalance between phases and neutral points.
In addition, the connection of three-phase transformers can also be represented by vector groups, such as Dyn11, Yyn0, etc. These symbols represent the winding connection and its relative phase displacement. The numerical indicators of the vector group come from the clock hour chart of the phase voltage hand (2U) of the high-voltage winding (1U) at 12 o'clock.
When selecting the appropriate connection method, it is necessary to consider the specific application requirements of the transformer, including factors such as voltage, current level, and the presence of neutral point requirements. The nameplate of a transformer usually specifies the type of connection to ensure proper installation and use