What type of polarity is standard for all single-phase distribution transformers?

The standard type of polarity for all single-phase distribution transformers is additive polarity. In transformers, polarity refers to the direction of the voltage induced in the secondary winding relative to the primary winding. In additive polarity, when you connect the primary and secondary windings in the designated polarity, the voltages add together, which is essential for creating the correct voltage levels in the distribution system.

This is important for maintaining system stability and ensuring that multiple transformers can be paralleled without issues. When transformers are paralleled, it's critical that their polarities match; otherwise, it can lead to short circuits, overloading, and other operational problems.

Transformers that exhibit additive polarity are typically marked to avoid confusion during installation, making it clear to technicians the proper way to connect them. Therefore, understanding the concept of additive polarity is crucial for anyone working with single-phase distribution transformers, ensuring safe and efficient operation within the electrical distribution network.