Why Distribution Transformer Connected In Delta Star

Distribution transformers are essential components in power transmission and distribution systems. They are responsible for stepping down the high voltage at the transmission side to low voltage levels that are suitable for supplying power to households and businesses. In most cases, distribution transformers are connected in delta-star configuration due to a number of reasons.
One of the primary reasons why distribution transformers are connected in delta-star configuration is to improve the efficiency of the system. Delta winding offers higher efficiency when compared to a star winding, which makes it an ideal choice for the high voltage side of the transformer. The delta winding is designed in such a way that it can handle a higher current while minimizing the voltage drop across the winding.
Another reason why distribution transformers are connected in delta-star configuration is to provide better protection against over-voltage. The delta winding on the high voltage side of the transformer provides a better buffer against over-voltage conditions, which can be caused by lightning, switching surges, or other disturbances in the system. This helps to protect the transformer from damage and ensures that the system remains functional even during adverse conditions.
Moreover, connecting distribution transformers in delta-star configuration also provides better fault protection. The delta winding provides a path for ground faults that occur on the high voltage side of the transformer. This helps to reduce the risk of damage to the transformer and other components in the system. Additionally, the star winding on the low voltage side of the transformer provides a neutral point which allows for better ground-fault protection.
In summary, connecting distribution transformers in delta-star configuration helps to improve system efficiency, provide better protection against over-voltage and reduce the risk of damage due to ground faults. This is why this configuration is commonly used in power transmission and distribution systems.