Substation Transformer: As Steady as a Rock, Ensuring Worry-Free Power Supply!
01 General
1.1 Project Description
3000 kVA substation transformer was delivered to Canada in 2025. The rated power of the transformer is 3000 kVA with ONAN cooling. The primary voltage is 44 kV with ±2*2.5% tapping range (NLTC), the secondary voltage is 0.6GrdY/0.347 kV, they formed a vector group of Dyn1.
This electrical substation is an efficient and stable power device that integrates advanced functions and various accessories, suitable for a wide range of power demands. Its main body is responsible for converting high and low voltage electrical energy, meeting user needs with high efficiency and stability. The marshalling box ensures the safety of electrical connections and operations, while the radiators enhance operational efficiency and equipment lifespan through effective thermal management. The high voltage cable box and low voltage cable box provide reliable connections for high and low voltage cables, designed to meet safety standards.
All accessories are housed inside a tamper-proof box, equipped with pentagon bolts on the external doors to prevent unauthorized access and tampering, thereby ensuring the safety of the equipment. This tamper-proof box contains important components such as the tap changer, pressure relief valve, liquid level indicator, fill valve, vacuum pressure gauge, liquid temperature indicator, and terminal box. These designs ensure the safety and stability of the equipment during operation. Overall, the design perfectly aligns with modern power demands, providing exceptional power transmission solutions in complex environments.
1.2 Technical Specification
3000 kVA electrical substation specifications type and data sheet
| Delivered to | Canada |
| Year | 2025 |
| Type | Substation transformer |
| Standard | CSA C88:16 |
| Rated Power | 3000 kVA |
| Frequency | 60HZ |
| Phase | 3 |
| Cooling Type | ONAN |
| Primary Voltage | 44 kV |
| Secondary Voltage | 0.6GrdY/0.347 kV |
| Winding Material | Aluminum |
| Angular displacement | Dyn1 |
| Impedance | 6% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 3.4kW |
| On Load Loss | 27.1kW |
| Accessories | Standard Configuration |
1.3 Drawings
3000 kVA electrical substation diagram drawing and size.
02 Manufacturing
2.1 Core
The iron core of a 3000kVA electrical substation utilizes a three-column design, with each column wound with a phase winding, allowing the three-phase alternating current to evenly distribute within the core. The core is made of high-quality cold-rolled grain-oriented silicon steel sheets which possess high magnetic permeability and low loss characteristics, thus enhancing efficiency and reducing energy losses. Its laminated structure, with insulating coatings, minimizes eddy current losses, making the core operate more efficiently.
2.2 Winding
 | Bushing mounted on the tank side wall inside full height cable box. The winding design of a low-voltage aluminum foil and high-voltage aluminum wire transformer is a common structure used in transformers. The low-voltage winding utilizes wide aluminum foil, providing good mechanical strength and thermal stability while effectively reducing leakage inductance and skin effect, enhancing current distribution uniformity and heat dissipation performance, making it suitable for low-voltage sides that carry larger currents. The high-voltage winding, on the other hand, employs round or rectangular aluminum wire to form a layered winding structure, which enhances insulation performance and voltage resistance, flexibly meeting the demands of the high-voltage side for electric field intensity. This design increases conductive capacity and improves heat dissipation on the low-voltage side, while providing good insulation and voltage resistance on the high-voltage side, thus satisfying the various electrical requirements and operational needs of the transformer. |
2.3 Tank
| First, high-strength, corrosion-resistant, and high-temperature-resistant steel is selected and cut using laser or plasma cutting technology to form the desired shape. Then, the cut pieces are shaped through cold bending or hot bending processes. Next, components are connected using gas metal arc welding or submerged arc welding techniques, ensuring high-strength welds and the tank’s seal integrity. After welding, surface treatment is performed, including shot blasting to remove impurities, followed by the application of epoxy resin or polyurethane coatings to enhance corrosion resistance and weatherproofing. |  |
2.4 Final Assembly
 | 1. Winding Installation: Install the primary and secondary windings on the core, adding insulation materials to ensure electrical insulation. 2. Tank Assembly: Place the assembled core and windings into the tank, filling it with insulating oil and ensuring sealing integrity. 3. Cooling System Integration: Connect the oil cooling system, such as radiators to control temperature. 4. Electrical Connections: Handle the electrical connections for high and low voltage sides, ensuring proper insulation. 5. Accessory Installation: Install various accessories such as bushings, tamper-proof boxes, marshalling boxes, vacuum pressure gauges, and liquid temperature indicators to ensure correct and secure operation. |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximum resistance unbalance rate | 3.24 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% | 0.08 | Pass |
| 3 | Phase-Relation Tests | / | Dyn1 | Dyn1 | Pass |
| 4 | No-Load Losses and Excitation Current | % kW | I0 :: provide measured value P0: provide measured value | 0.25 3.004 | Pass |
| 5 | Load Losses Impedance Voltage and Efficiency | % kW kW | t:85℃ Z%: measured value Pk: measured value Pt: measured value the tolerance for impedance is ±7.5% Efficiency not less than 99.37% | 6.16 24.858 27.862 99.43 | Pass |
| 6 | Applied Voltage Test | kV | HV: 95kV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | kV | Applied voltage (KV): 2 Ur Duration(s):40 Frequency (HZ): 180 | No collapse of the test voltage occurs | Pass |
| 8 | Leakage Test | kPa | Applied pressure：50kPA Duration：12h | No leakage and no Damage | Pass |
| 9 | Insulation Resistance Measurement | GΩ | HV-LV to Ground : LV-HV to Ground: HV&LV to Ground: | 25.5 10.4 16.1 | Pass |
| 10 | Oil Test | kV, mg/kg, %, mg/kg, | Dielectric Strength; Moisture Content; Dissipation Factor; Furan Analysis ; Gas Chromatography Analysis | 58.3 10.6 0.096 ≤0.1 / | Pass |
04 Packing and Shipping
4.1 Packing
| The electrical substation is packed in a wooden crate, wrapped with a moisture-proof aluminum foil bag to ensure protection against dust and humidity during transportation and storage. The sturdy wooden crate includes internal cushioning to prevent shock and vibration damage. |  |
4.2 Shipping
 | The transportation of a substation transformer under CIF (Cost, Insurance, and Freight) conditions to the port of Toronto includes several key steps. First, the transformer is inspected to ensure all components are secure and undamaged, and necessary shipping documents are prepared. It is then packaged properly to prevent damage during transit, using wooden frames and cushioning materials, with clear labeling. The transformer is loaded into a shipping container using appropriate lifting equipment to prevent movement. Sea freight is typically used, and insurance is purchased to cover potential damage or loss. Upon reaching Toronto, the transformer undergoes import clearance, and the carrier handles communication with the port and customs. After clearing customs, it is safely unloaded and transported to its final destination, following safety protocols for a smooth delivery process. |
05 Site And Summary
In conclusion, substation transformers play a crucial role in the power system. They not only facilitate the safe conversion and distribution of high-voltage electrical energy but also ensure that power is reliably supplied to various users. The performance of substation transformers directly affects the reliability and efficiency of the power network, making it essential to give high importance to the selection, installation, and maintenance processes. In the context of growing electricity demand and the increasing integration of renewable energy sources into the grid, the significance of advanced transformer technologies and their infrastructure has become even more pronounced. Through continuous innovation and enhancement of sustainability, we can ensure the stability and environmental friendliness of future power systems to meet the needs of socio-economic development.
