Understanding Third Harmonic Flux in Transformers — Lesson 11

This lesson covers the impact of third harmonic flux and currents in three-phase transformers. It explains the issues caused by a star connection without neutral, such as the impossibility of single-phase loading and an oscillating secondary neutral. The lesson further discusses how a delta connection in either primary or secondary can prevent the existence of any third harmonic current in the lines. It also delves into the induced voltage in the coils and the magnitude of the circulating third harmonic current.

Video Highlights

00:45 - Explanation of the effect of the delta connection in primary or secondary transformers
09:23 - Discussion on the use of the tertiary winding in the transformer
13:26 - Explanation of the use of the delta zigzag connection in the transformer
23:10 - Discussion on the use of the Delta zigzag connection in the transformer
34:52 - Conclusion of the lecture and a preview of the next lecture

Key Takeaways

• A star connection without neutral in three-phase transformers can lead to problems like oscillating secondary neutral and impossibility of single-phase loading.
• A delta connection in either primary or secondary can prevent the existence of any third harmonic current in the lines.
• The coils in the transformers can have induced voltage due to the third harmonic flux