Empowering intelligent energy, driving future efficiency - Power Transformer, illuminating the world!
01 General
1.1 Project Description
18.75 MVA OLTC cooper power transformers was delivered to Australia in 2023. The rated power of the transformer is 18.75 MVA with ONAN/ONAF cooling. The primary voltage is 66 kV with ±8*1.25% tapping range (OLTC), the secondary voltage is 11.55 kV, they formed a vector group of Dyn1.
This 18.75 MVA, 66 kV cooper power transformers combines advanced technology with exceptional structural design, aimed at meeting various critical power delivery needs. Equipped with an On-Load Tap Changer (OLTC), it allows for dynamic voltage regulation, ensuring the stability and efficiency of the power grid. The integrated Buchholz relay facilitates early fault detection, providing reliable protection for transformer operation, while the winding temperature indicator continuously monitors the operational temperature, preventing overload and overheating issues. The integrated marshalling box supports convenient wiring and control system management, greatly enhancing installation and maintenance efficiency.
Manufactured with high-quality materials and expert craftsmanship, transformer produced by SCOTECH is capable of withstanding harsh operating environments and is suitable for use in power plants, industrial power supply, and grid transmission.
1.2 Technical Specification
18.75 MVA OLTC cooper power transformers specifications type and data sheet
| Delivered to | Australia |
| Year | 2023 |
| Type | OLTC step down power transformer |
| Standard | IEC60076 |
| Rated Power | 18.75 MVA |
| Frequency | 50HZ |
| Phase | 3 |
| Cooling Type | ONAN/ONAF |
| Primary Voltage | 66 kV |
| Secondary Voltage | 11.55 kV |
| Winding Material | Copper |
| Angular displacement | Dyn1 |
| Impedance | 10.05% |
| Tap Changer | OLTC |
| Tapping Range | ±8*1.25% |
| No Load Loss | 15.548kW |
| On Load Loss | 78.988kW |
| Accessories | Standard Configuration |
1.3 Drawings
18.75 MVA OLTC cooper power transformers diagram drawing and size.
02 Manufacturing
2.1 Core
| The iron core of our cooper power transformers is essential for optimizing efficiency and performance. We select high-permeability silicon steel sheets, rigorously tested to minimize energy loss while maximizing magnetic flux density. Enveloped in quality insulating materials, the core ensures long-term reliability. Our advanced manufacturing processes, including precision stamping and laser cutting, enhance material efficiency and reduce assembly errors. The laminated structure significantly lowers eddy current losses, improving energy conversion. |  |
2.2 Winding
 | Our transformer windings are expertly designed to handle demanding electrical and mechanical conditions. The high-voltage (HV) windings feature entangled or inner-screened configurations, ensuring robust phase insulation and dielectric strength for reliable operation. For medium-voltage (MV) and low-voltage (LV) applications, we use high-strength or transposed conductors that enhance electrical performance and enable forced cooling, reducing temperature rise. This design improves the windings’ ability to withstand short-circuit conditions, ensuring safety and durability. We apply various construction techniques, such as interleaved, shielded disk, helical, and layered designs, tailored to each transformer’s voltage and impulse ratings. Our commitment to precision in coil winding guarantees optimal efficiency, reliability, and long service life, making our transformers ideal for demanding applications. |
2.3 Tank
| Transformer tank is equipped with a high-quality oil tank made of corrosion-resistant steel, treated with rigorous anti-corrosion processes to ensure durability and reliability in various environments. The oil tank utilizes advanced welding techniques to guarantee joint strength and sealing, preventing oil leakage. A meticulous surface treatment enhances both corrosion resistance and aesthetic quality. The internal design is optimized to promote smooth oil flow, improving heat exchange and cooling performance, which in turn enhances the operational efficiency of the transformer. |  |
2.4 Final Assembly
 | Core components such as the core, windings, and oil tank undergo thorough inspection before assembly, utilizing high-precision positioning technology to optimize electromagnetic characteristics and ensure efficiency and stability. All electrical connections and mechanical fixings adhere to industry standards, enhancing safety and durability. The cooling system is carefully designed to ensure efficient heat dissipation under various load conditions. |
03 Testing
1) Measurement of insulation
2) Measurement of voltage ratio and check of phase displacement
3) Current transformer measurement
4) Measurement of winding resistance
5) Measurement of No-load losses and No-load current
6) Measurement of short circuit impedance and load losses
7) On-load tap changer-operation test
8) Lightning impulse test
9) Applied voltage test
10) Induced voltage withstand test with pd measurement
11) Temperature rise test
12) Seal test
13) Insulation oil test
04 Packing and Shipping
05 Site And Summary
Thank you for your interest in our power transformers! With exceptional performance, reliable quality, and efficient energy conversion capabilities, our transformers provide the optimal solution for your business and engineering projects. Whether you seek stable operation or energy efficiency, we are here to meet your needs. We look forward to collaborating with you to achieve a brighter future together! Please feel free to contact us for more information or assistance.
