What is the difference between transformer delta connection and Y?

About the Transformer wiring method, but from the skills where to get dry goods, I hope that our company's sharing can give parents a further understanding of transformer knowledge.

According to the practical wiring, the primary and secondary side voltage and meet the requirements, the primary high-voltage side of the transformer is usually connected as a star, while the secondary low-voltage side is usually triangular. The main reason is that as the star connection method of the high-voltage side, according to the relevant algorithm, it can limit the fault current of the system and the transformer body to the maximum extent, and facilitate the protection action of the secondary relay protection If the high pressure side is triangular, the above requirements cannot be met.

The primary side and secondary side of the transformer are respectively Y-type (star type), D-type (triangle type) and Z-type (zigzag type) connection methods. When the primary side is triangular and the secondary side is star shaped, i.e. D / yn connection method, when the secondary side (commercial power) three-phase load is unbalanced or only bears single-phase load, the primary side current of corresponding phase is directly connected to another phase line through the end of winding, and then the vector sum of its residual phase is added, The copper loss and voltage regulation rate will be lower. If it is star connection, the same star crossing point will form a series circuit with the other two phases to generate vector sum. In this way, the copper loss and voltage regulation rate should be slightly larger. When the three-phase balance is balanced, the difference is not significant. If the three-phase balance is met, it can be connected in any way. If it is unbalanced or the compliance is mostly single, star connection is recommended.