A power transformer is a type of electrical transformer used in power systems to transfer electrical energy between different voltage levels. It is a crucial component in electrical transmission and distribution networks, converting high-voltage power from generators to lower voltages suitable for distribution to consumers.
Key topics related to power transformers:
- Construction – Core materials and design, windings, insulation materials and systems, cooling methods, tap changers, tanks and accessories. Understanding construction is critical for proper operation and maintenance.
- Ratings – Voltages, power handling capability, impedance, losses, insulation levels, temperature rise limits. These parameters determine intended usage and capabilities.
- Connections – Common winding connections like delta-star, delta-delta, star-star, etc. Affects phase shifts, grounding, and ability to step voltage up/down.
- Vector Groups – Phase shift characteristics of different winding connections. Important for understanding paralleling and system phase relations.
- Cooling – Methods like ONAN, ONAF, OFAF, ODWF, etc. Affects power handling ability and overall size/cost.
- Tap Changers – Off-load tap changers and on-load tap changers for changing turn ratio in energized transformers. Allows voltage control.
- Parallel Operation – Considerations for operating transformers in parallel on a bus or grid. Must match parameters like voltage, impedance, and phase shift.
- 3-phase transformer problems and solutions – Phase angle displacement, phase imbalance, zero-sequence impedance. Affects transformer capability in three-phase circuits.
- Short Circuit Analysis – Transformer behavior during faults. Critical for setting protective relays and ensuring winding integrity.
- Testing and Maintenance – Acceptance testing, preventive maintenance, monitoring key parameters, interpretation of dissolved gas analysis. Essential for reliability.
- Standards – Design, testing, and performance standards from IEEE, IEC, ANSI and others. Ensures proper application and operation.