Transformer for a 1 MW Solar Plant: Step-Up or Distribution?

A 1 MW solar plant can use a step-up transformer, a distribution transformer or a prefabricated station. The right choice depends on the grid interface and layout.

Define the grid interface first

Start with the point of connection, the grid voltage and the utility’s protection and metering requirements. A 1 MW plant may connect at 10 kV, 20 kV or 35 kV, and the transformer ratio follows that interface. The inverter output voltage, AC collection philosophy and the allowed fault level also shape the design.

Step-up vs distribution

A step-up transformer raises the inverter output to the collection or grid voltage. A distribution transformer may be used inside the plant for auxiliary loads or a lower-voltage section. Do not assume one transformer type covers both duties; the impedance, tap range and protection may differ.

Prefabricated station option

For a compact site, a YB or ZGS prefabricated station can integrate the transformer, MV switchgear and LV distribution in one enclosure. This reduces civil works and cable interfaces, but the station layout and access must be agreed early.

FAQ

What size transformer for 1 MW?

The transformer rating depends on the inverter AC output, power factor, overload and future expansion. A 1,000–1,250 kVA range is common, but the datasheet must be based on the actual inverter and grid study.

Do I need a step-up transformer?

If the inverter output is lower than the grid connection voltage, yes. The ratio and impedance are part of the grid-connection design.

Can I use a distribution transformer?

Only if its insulation, impedance and protection suit the grid interface. A distribution transformer is not automatically a solar step-up transformer.

Related pages

• Photovoltaic solutions
• Transformer stations
• ZGS pre-assembled substation