Eco-friendly pioneer, exceptional quality, resin cast transformer empowering the future!
01 General
1.1 Project Description
250 kVA resin cast dry type transformer was delivered to Georgia in 2025. The rated power of the transformer is 250 kVA with ONAN cooling. The primary voltage is 10 kV with ±2*2.5% tapping range (NLTC) by tapping links, the secondary voltage is 0.4 kV, they formed a vector group of Dyn11.
This resin-encapsulated dry-type transformer features an advanced design aimed at achieving efficient and stable power transmission. Its temperature control system consists of a China-made E-type temperature controller and four independent PT100 temperature probes. Three PT100 probes are specifically designated for monitoring the winding temperature, while one probe is used for monitoring the core temperature. This flexible configuration ensures precise temperature management under various operating conditions, effectively preventing overheating risks and extending the lifespan of the equipment.
Additionally, the transformer is equipped with a current transformer (CT) for detecting ground fault currents on the low-voltage side, enabling rapid fault identification and significantly enhancing the safety and reliability of the system. With its exceptional performance, durable design, and outstanding safety features, this transformer has become a key component in modern power systems, providing stable and reliable power assurance for various applications.
1.2 Technical Specification
250 kVA resin cast dry type transformer specification and data sheet
| Delivered to | Jamaica |
| Year | 2025 |
| Type | Resin cast dry type transformer |
| Core material | Grain oriented silicon steel sheet |
| Standard | IEC60076 |
| Rated Power | 250kVA |
| Frequency | 50HZ |
| Vector group | Dyn11 |
| Phase | 3 |
| Cooling Type | ONAN |
| Primary Voltage | 10 kV |
| Secondary Voltage | 0.4 kV |
| Winding Material | Aluminum |
| Impedance | 6% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5%@primary side by tapping links |
| No Load Loss | 0.52KW |
| On Load Loss | 3.8KW |
| Insulation level | F |
1.3 Drawings
250 kVA resin cast dry type transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| The core of the resin-cast dry-type transformer is a crucial component, made of high magnetic permeability steel plates and designed in a laminated structure to reduce eddy current losses and enhance efficiency. An insulating coating is applied between the laminations to prevent short circuits, optimize the magnetic circuit, and ensure effective current transmission. This design maintains stable performance in high-temperature and humid environments, while also providing good heat dissipation capabilities to effectively release heat generated during operation, preventing overheating. The compact structure of the core allows the transformer to be installed and operated normally in space-constrained environments, thereby improving overall efficiency and safety, while increasing durability. |  |
2.2 Winding
 | The coil of the resin-cast dry-type transformer is a crucial component responsible for the conversion and transmission of electrical energy, significantly impacting performance and efficiency. Made from high-performance insulating materials, it offers excellent insulation and high-temperature resistance to prevent current leakage. The coil features precise winding techniques for tight wire arrangement and uniform distribution, enhancing electrical performance and reducing inductive losses. Designed for efficient heat dissipation during operation, it prevents damage from overheating. The coil undergoes resin casting for solidification, which strengthens its density and stability, ensuring consistent performance under varying conditions. Additionally, the resin material provides corrosion resistance, allowing it to function reliably in humid or polluted environments, enhancing durability. |
2.3 Final Assembly
| 1. Coil Fixing: Securely install the pre-cast coils onto the core according to design requirements, ensuring that the direction, connection methods, and spacing of the coils comply with design specifications to guarantee normal electrical performance. 2. Electrical Connections: Connect the high-voltage and low-voltage cables, ensuring all connections are secure and meet standards. 3. Accessory Installation: Install various accessories such as wheels, insulators, temperature controllers, PT100 temperature probes, and CTs (current transformers) to ensure the proper functioning of auxiliary equipment. |  |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion | |
| 1 | Measurement of winding resistance | / | Maximum resistance unbalance rate Line resistance:≤2% | HV (line) | LV (line) | Pass |
| 0.41% | 0.61% | |||||
| 2 | Measurement of voltage ratio and check of phase displacement | / | The tolerance of voltage ratio on the principal tapping: ±1/10 Connection symbol: Dyn11 | 0.03% ~ 0.13% Dyn11 | Pass | |
| 3 | Measurement of Short-circuit Impedance and Load Loss | / kW kW | t:120℃ Z%: measured value Pk: measured value Pt: measured value | 6.14% 2.458 3.455 | Pass | |
| 4 | Measurement of No-load Loss and Current at 90% and 110% of rated voltage | / kW | I0 :: provide measured value P0: provide measured value | 90% Ur | 0.50 0.437 | Pass |
| 100% Ur | 0.56 0.486 | |||||
| 110% Ur | 0.616 0.534 | |||||
| 5 | Applied Voltage Test | / | HV: 28kV 60s LV: 3kV 60s | No collapse of the test voltage occurs | Pass | |
| 6 | Induced Voltage Withstand Test | / | Applied voltage (KV): 2 Ur Induced voltage (KV): 0.8 Duration(s):40 Frequency (HZ): 150 | No collapse of the test voltage occurs | Pass | |
| 7 | Partial Discharge Test | pC | The maximum level of partial discharges shall be 10 pC | ＜10 | Pass | |
04 Packing and Shipping
05 Site And Summary
In conclusion, the resin cast dry type transformer stands as a testament to innovation in electrical engineering, offering enhanced safety, reliability, and environmental resilience compared to traditional transformers. Its robust design and superior insulation properties ensure optimal performance in various applications, making it an ideal choice for modern power distribution systems. As industries increasingly prioritize sustainability and energy efficiency, the resin cast dry type transformer is set to play a pivotal role in shaping the future of energy transmission. Its ability to operate in diverse environments, coupled with minimized maintenance requirements, positions it as a key asset in meeting the growing demand for reliable and eco-friendly power solutions. As we continue to advance in technology and energy needs, the resin cast dry type transformer will undoubtedly remain at the forefront of electrical infrastructure development.
