Number of MV/LV transformers
From Electrical Installation Guide
Main characteristics to consider to determine the number of transformers:
- Surface of building or site
- Total power of the installed loads
- Sensitivity of circuits to power interruptions
- Sensitivity of circuits to disturbances
- Installation scalability
The basic preferred configuration comprises a single transformer supplying the total power of the installed loads. Certain factors contribute to increasing the number of transformers (> 1), preferably of equal power:
- A high total installed power (> 1250kVA): practical limit of unit power (standardization, ease of replacement, space requirement, etc),
- A large surface area (> 5000m²): the setting up of several transformers as close as possible to the distributed loads allows the length of LV trunking to be reduced
- A need for partial redundancy (down-graded operation possible in the case of a transformer failure) or total redundancy (normal operation ensured in the case a transformer failure)
- Separating of sensitive and disturbing loads (e.g.: IT, motors)
