Oil-Immersed Step-up Transformer Solution for Solar Power Plant Grid Connection

Application Background

Solar power plants generate electrical energy through photovoltaic modules and inverters. Before connecting to the medium-voltage collection network or utility grid, the low-voltage AC output needs to be transformed to the required voltage level.

An oil-immersed step-up transformer provides an important connection between the power generation system and the electrical grid.

For solar project developers, EPC contractors and electrical equipment distributors, selecting a suitable transformer requires consideration of power capacity, voltage ratio, operating conditions and grid connection requirements.

Transformer Application and System Configuration

A typical solar power generation system includes:

• Photovoltaic modules

• Solar inverters

• AC distribution and protection equipment

• Oil-immersed step-up transformers

• Medium-voltage collection lines and grid connection equipment

The transformer increases the inverter-side AC voltage to the designated medium-voltage level for power collection and transmission.

Customized Oil-Immersed Transformer Design

Transformer specifications should be determined according to the actual solar project configuration rather than using a universal rating.

Key selection considerations include:

• Rated capacity based on inverter output and project loading requirements

• Primary and secondary voltage according to inverter and grid specifications

• Three-phase configuration and suitable vector group

• Copper or aluminum winding options

• ONAN cooling configuration where applicable

• Insulation level, temperature rise and environmental conditions

For outdoor solar installations, tank protection, corrosion resistance, cooling performance and suitable accessories should also be considered.

Manufacturing and Quality Inspection

A reliable transformer solution requires attention throughout the manufacturing process, from electrical design and material selection to winding, core assembly, tank fabrication and final inspection.

Applicable routine tests and additional project-specific tests can be arranged according to the agreed technical specifications and relevant standards.

Customized Transformer Support from TNNPI

New Electric Power (TNNPI) provides transformer manufacturing and customization services for different electrical applications.

For solar power plant projects, customers can share their inverter output voltage, grid voltage, required capacity, frequency and installation conditions.

Our engineering team can use these requirements as the basis for discussing a suitable oil-immersed step-up transformer configuration.

Looking for an oil-immersed step-up transformer for your solar project? Contact TNNPI to discuss your technical requirements and customized solution.