Electrical Engineering XYZ MCQs
In which transformer, the tertiary winding is used:
- Delta-Delta
- Star-Delta
- Delta-Star
- Star-Star
Correct answer: 4. Star-Star
Explanation: In Star-Star transformers, a tertiary winding, which is often delta-connected, is sometimes added. The purpose of adding a delta-connected tertiary winding to a Star-Star transformer is multifaceted. Firstly, it helps to provide a path for zero sequence currents, which cannot flow through the star-star primary and secondary windings due to their lack of a direct path for such currents. Secondly, it aids in the suppression of harmonic generation in the power system. This tertiary winding thus stabilizes the system by balancing out unbalanced loads and improving the overall fault tolerance of the system. Additionally, this setup can help in enhancing the voltage regulation of the transformer under varying load conditions. This application is particularly important in large power distribution networks where stability and harmonic control are critical.