Purpose of transformer
Transformers are designed to do one of the following:
- Step-up voltage; consequently step-down current – enables long-distance transmission by reducing I^2\times R copper losses. Step-ups are found near generating stations.
- Step-down voltage; consequently step-up current – enables distribution of power to customers at a safe voltage magnitude. Step-downs are found near load centers and in sub-transmission systems.
- On distribution transformers, when equipped, the load tap changer keeps the secondary voltage constant as the load increases or decreases.
- Transformer are also designed for special applications such as phase shifting transformer (pushes more power on a t-line by varying power-angle \sin\delta – learn more), HVDC converter transformer, SVC transformer, grounding zig-zag transformer etc.
Cost of transformer
The cost of a power transformer varies significantly based on BIL rating, MVA rating, core design, guaranteed losses requirement, tank design, etc. The prices listed below are for a standard design transformer.
- Small power transformer with LTC ~10MVA or lower: ~ $600,000
- Medium power transformer with LTC ~50MVA or lower: ~$1,400,000
- Large power transformer ~300MVA or lower: ~ $3,500,000
- Large phase shifting speciality transformer: ~$5,000,000
Lead time to procure transformer
~ 1 year, regardless of MVA rating.
Information on cost and lead-time are rough estimates — contact vendor with your equipment specifications for actual figures.