Power Transformer

66/69 kV Power Transformer

A project-engineered oil-immersed transformer for 66 kV and 69 kV systems, balancing compact transport dimensions with dependable grid performance.

Rated voltage: 66 kV or 69 kV
Capacity range: 10–120 MVA
Standards basis: IEC or ANSI/IEEE - select configuration
Typical application: regional transmis…

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Technical product selection

Product Range

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Select the voltage, capacity and construction that matches the project. Final ratings are confirmed during technical review.

Typical Use

Where this product is used

regional transmission, renewable interconnection and industrial substations

Technical Data

Typical technical parameters

Available as a clearly defined IEC or ANSI/IEEE design. Voltage class, frequency, insulation coordination, terminals and testing follow the selected configuration.

Design standardIEC 60076 series

Configuration66 kV · typically 50 Hz

Design basis

IEC 60076-1 and applicable parts

HV rated voltage

66 kV

System frequency

50 Hz, or project frequency where specified

Connection and vector group

IEC vector-group designation, project-specific

Insulation coordination

Selected to IEC requirements and the system insulation study

Rated capacity

10–120 MVA

Phase

Three-phase

LV rated voltage

Project-specific, coordinated with the system single-line diagram

Tap changing

OLTC or off-circuit taps according to voltage-regulation study

Short-circuit impedance

Project-specific; confirmed against fault level and parallel-operation requirements

Cooling

ONAN / ONAF, with forced-oil stages where the rating requires

Insulating liquid

Mineral oil or approved natural/synthetic ester

Losses and efficiency

Guaranteed values agreed during technical review

Ambient and altitude

Site-specific; correction applied where standard service conditions are exceeded

Monitoring and protection

Temperature, pressure, oil level and optional online condition monitoring

Testing

Routine tests plus agreed type and special tests

These values are for product selection. Final guaranteed values are confirmed in the approved technical agreement.

Configuration

Details to confirm before production

Confirm these items so the quotation and product design match your project.

Network study inputs

Rated voltages, highest system voltage, fault level, neutral earthing, load cycle and parallel-operation data establish the electrical baseline.

Voltage regulation

Select OLTC or off-circuit tapping from the permissible voltage variation, regulating range and operating philosophy.

Thermal and acoustic duty

Confirm continuous and emergency loading, cooling stages, ambient profile, temperature rise and site sound limits.

Transport envelope

Maximum shipping mass, route height, rail or road restrictions and site assembly scope must be reviewed before design release.

Normal supply

Typical standard equipment

Main tank and removable radiator banks
HV/LV bushings and neutral terminal as specified
Oil and winding temperature indicators
Pressure relief and oil-level indication
Control cabinet and marshalling wiring
Earthing pads, lifting lugs and jacking points

Project options

Common optional equipment

On-load tap changer and automatic voltage control
Dissolved-gas, bushing or partial-discharge monitoring
Natural ester insulating fluid
Online moisture and temperature monitoring
Neutral current transformer and surge arresters
Transport impact recorder and nitrogen preservation

Testing and Documents

Tests and documents supplied with the product

The required tests and documents are confirmed before the order is placed.

Routine verification

Tests required for each completed unit under the selected product standard.

Design and type evidence

Applicable type-test evidence or agreed design verification is reviewed during technical approval.

Special testing

Sound, temperature-rise, impulse, partial-discharge or other special tests are included only when specified.

Document package

Approved drawings, data sheets, test reports, manuals, packing list and agreed quality records.

Packing and Delivery

Heavy-transformer transport planned before design release

The shipping envelope, transport mass and site access are reviewed early because they can affect tank dimensions, removable parts and the final delivery method.

Main unit preservation

The active unit and main tank are protected against moisture ingress. Nitrogen preservation or another agreed method is used when required by the transport plan.

Removable parts and oil

Bushings, radiators, conservator parts, coolers and accessories may be packed separately. Insulating liquid shipment is coordinated with route and regulatory limits.

Heavy-lift transport

Centre of gravity, lifting and jacking points, transport dimensions and maximum shipping mass are issued for route and crane planning.

Arrival and assembly records

Packing lists identify loose parts and erection items. Impact records, oil records and agreed assembly instructions accompany the delivery package.

A project-engineered oil-immersed transformer for 66 kV and 69 kV systems, balancing compact transport dimensions with dependable grid performance.

Replacement or parallel unit? Compare the existing unit with our transformer nameplate guide. If it will share a bus with another transformer, review the parallel-operation requirements before finalizing ratio, vector group, taps and impedance.

Product overview

66/69 kV Power Transformer is configured for regional transmission, renewable interconnection and industrial substations. Apex coordinates technical review, qualified production, documentation and export delivery according to the approved project requirements.

Applications

regional transmission, renewable interconnection and industrial substations. Final design considers the system study, load profile, fault level, installation environment, efficiency targets and local grid requirements.

Quotation Information

What to include with your inquiry

Send the information you already have. Unknown items can be confirmed during technical review.

Rated power (MVA)
High- and low-voltage ratings
Frequency and applicable standard
Impedance and loss requirements
Vector group and tap range
Installation altitude and ambient temperature
Terminal arrangement
Quantity
Destination country and delivery location

FAQ

Questions buyers usually ask

How are impedance and losses selected?

They are coordinated with system fault level, voltage regulation, parallel operation and lifecycle cost. Final guaranteed values belong in the approved technical schedule.

When is an OLTC required?

An OLTC is normally considered where system voltage must be regulated while the transformer remains energized. The regulating range and number of steps follow the network study.

Are guaranteed values the same as the website values?

No. Website values are selection guidance. Guaranteed performance is stated in the approved technical data sheet and commercial offer.

What information helps Apex respond faster?

A single-line diagram, load data, voltage ratio, capacity, quantity, installation conditions, destination and required delivery date provide the best starting point.

Applications

Choose equipment for the site and operating conditions.

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Technical Articles

Product selection and application guides.

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TECHNICAL ARTICLE

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66/69 kV Power Transformer

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