TRANSFORMER APPLICATION

Transformers for Solar Power Plants

Start with the transformer's role in your solar plant: connecting an inverter block, replacing existing equipment or supplying auxiliary loads. Share the inverter documentation, electrical design and site requirements so the transformer offer can be reviewed against a defined duty, not just the plant's headline MW capacity.

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Start with your project task

Connect a new inverter block

Specify the transformer between the inverter AC output and the plant's collection system. Its duty is different from the final grid-interconnection transformer.

Send these inputs: Inverter manufacturer, model and quantity; current transformer-interface requirements; AC output data; single-line diagram; required collection voltage; proposed transformer rating; project country and specification.
Review and coordination: Establish the winding arrangement, electrical ratings and terminal interfaces required by the selected inverter system. The inverter supplier and project designer confirm compatibility and any limits that the transformer proposal needs to meet.
Expected output: A defined inverter-block transformer requirement, with the offered configuration, outstanding interface questions and the equipment included in the quotation.

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Repower a block or replace a transformer

A new inverter model or added generation can change the required transformer duty even when the installation footprint stays the same.

Send these inputs: Existing transformer nameplate and drawings, current and proposed inverter data, as-built single-line diagram, terminal and foundation measurements, operating records where available, and the intended replacement window.
Review and coordination: Compare the old and proposed electrical duty, winding arrangement and physical interfaces. Identify which existing connections can be retained and which need the project team's review; do not assume a same-capacity unit is interchangeable.
Expected output: An interface comparison and list of unresolved changes for a replacement or repowering quotation, with site installation responsibilities separated from equipment supply.

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Supply plant auxiliary services

Control buildings, cooling equipment, maintenance facilities and other station loads need their own supply assessment, separate from exported PV power.

Send these inputs: Auxiliary load schedule, supply source, required voltage and frequency, motor or drive details, indoor or outdoor location, enclosure requirements, and any essential-load or standby arrangements.
Review and coordination: Identify the auxiliary transformer duty and its connection point. Equipment powered from an inverter output may have different interface requirements from equipment supplied by the plant distribution system.
Expected output: A separate auxiliary-supply requirement and category route, with the load, installation and document assumptions available for technical comparison.

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Conditions that affect configuration

Inverter model and winding compatibility

The permitted winding connections and inverter grouping depend on the inverter family. Harmonic currents and switching-related insulation requirements also need the relevant manufacturer's data; a generic inverter-duty label does not prove compatibility.

Information to provide: The exact inverter model and manual revision, proposed grouping, required winding arrangement, earthing instructions, AC current data and any specified harmonic, shielding or insulation requirements.

Collection network and grid interface

The transformer voltage ratio, impedance and protection interfaces need to fit its position in the electrical design. A block step-up transformer does not by itself establish acceptance of the complete plant at the grid connection point.

Information to provide: Winding rated voltages, system nominal and highest voltage requirements, frequency, specified impedance, fault-duty information, tap requirements, earthing arrangement, and the applicable utility or project specification.

Operating profile, temperature and losses

Generation varies over time, and the thermal basis depends on the actual operating profile and site conditions. Include any required reactive-power service or storage-related operation. Compare load and no-load losses using agreed conditions instead of an unqualified low-loss claim.

Information to provide: Expected loading profile, ambient-temperature range, altitude, required operating modes, loss evaluation conditions, cooling assumptions and any limits specified by the owner or electrical designer.

Outdoor exposure and installation interfaces

Dust, moisture, corrosion exposure and the installation arrangement affect enclosure, cooling and maintenance requirements. A transformer-only quote is not the same scope as a complete inverter station or prefabricated skid.

Information to provide: Site environmental specification, location layout, access and foundation constraints, cable or busbar entry, terminal arrangement, fire and containment requirements where applicable, monitoring interfaces and the required accessory list.

Explore suitable product options

Oil-immersed transformers

Explore this range for outdoor transformer installations where the project permits liquid-filled equipment. Confirm the required solar duty, inverter interfaces, cooling, containment and accessory scope for the proposed configuration.

Review product range

Dry-type transformers

Explore this range for suitable auxiliary distribution or installations requiring an oil-free transformer. Any inverter-connected duty still needs model-specific electrical and thermal review; the installation location alone does not establish suitability.

Review product range

Documents by project stage

RFQ and supply-scope comparison

Include the inverter requirements and project specification with the RFQ. Compare the proposed ratings, winding arrangement, loss conditions, accessories and exclusions. Identify whether the quotation covers only the transformer or any separately agreed equipment and services.

Stage: quotation

Configuration and interface agreement

Confirm the configuration-specific outline, dimensions and weight, terminal positions, nameplate data and accessory interfaces required for project review. Resolve technical deviations before treating a drawing or data sheet as the agreed supply basis.

Stage: design approval

Inspection and delivery records

Agree the inspection plan, acceptance criteria and required test records before ordering. Identify any special or witnessed tests separately. Confirm the manuals and shipping documents needed for receipt, with installation, protection settings and energization assigned to the responsible project team.

Stage: delivery

Scope and coordination

The transformer proposal covers the equipment and documents expressly agreed in the quotation. The project designer, inverter supplier and grid operator retain their respective roles in plant design, compatibility confirmation and grid acceptance. Whole-plant yield, protection coordination, commissioning and complete inverter-station delivery are not implied by a transformer enquiry.

Questions before requesting a quotation

Can I select the transformer from the solar array's DC MW rating alone?

No. The array rating does not fully describe the AC equipment connected to the transformer or its operating duty. Start with the selected inverter data, electrical arrangement and project requirements; have the design team confirm the rating basis.

Can several inverters share one transformer winding?

It depends on the inverter system. Some manufacturer-defined arrangements permit shared connections, while others require separate isolated windings. Provide the exact model and current interface documentation instead of assuming a standard connection.

Can the same transformer duty be used after adding battery storage?

Do not assume that a solar-only duty remains suitable. Storage can change power-flow direction, operating hours and the thermal profile. Send the proposed combined operating requirements for a fresh equipment review.

What should I send if the project specification is incomplete?

Send the inverter information, single-line diagram and site details you already have, together with the known voltage, quantity and schedule. Identify unresolved requirements so the next discussion can focus on the missing decisions rather than guessed parameters.

Send your project requirements

Share the voltage, capacity, installation conditions and project specification. A document link is optional.

Request a Technical Discussion