No fire, no smoke, environmentally friendly – Resin cast dry type transformers lead the way!
01 General
1.1 Project Description
We are pleased to announce that our company will be exporting a high quality castable dry transformer to South Africa. The specific specifications of the transformer are as follows: the rated capacity is 500kVA, the primary voltage is 13.8 kV and secondary voltage is 0.46 kV with delta star connection. The transformer is equipped with NLTC no load tap changer, the tapping range is ±2*2.5% at primary side, the cooling is AN, the connect group is Dyn11. Cast resin technology provides excellent insulation and environmental protection, this together with the foil winding technology inside the resin offers the ultimate dry type transformer in terms of dielectric performance and short circuit withstand ability and ensures long term reliability for both distribution and special applications. Another noteworthy feature of the transformer is its aluminum winding. This makes it lighter and easier to install, while still providing exceptional performance.
With continual innovation, optimisation and customer-oriented solutions, various type of transformer produced by SCOTECH have operated worldwide.
1.2 Technical Specification
500 kVA resin cast dry type transformer specification and data sheet
| Delivered to | South Africa |
| Year | 2024 |
| Model | 333KVA-2.4(7.2)/0.6KV |
| Type | Resin cast dry type transformer |
| Core material | Grain oriented silicon steel sheet |
| Standard | IEC 60076 |
| Rated Power | 500KVA |
| Frequency | 50HZ |
| Phase | Three |
| Cooling Type | ONAN |
| Primary Voltage | 13.8 KV |
| Secondary Voltage | 0.46 KV |
| Winding Material | Aluminum |
| Impedance | 6% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5%@primary voltage |
| No Load Loss | 1.4KW |
| On Load Loss | 5.2KW |
| Accessories | Standard Configuration |
| Remarks | N/A |
| Insulation level | F |
1.3 Drawings
500 kVA resin cast dry type transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| The main function of the transformer core is to form the magnetic circuit coupling magnetic flux, to reduce the exciting current, at the same time as the skeleton of the transformer body. The transformer core is composed of silicon steel sheets, the design aims to improve the magnetic conductivity of the magnetic circuit, reduce the excitation current and eddy current hysteresis loss. silicon steel sheet not only has good magnetic conductivity, and is stacked into an iron core by insulating each other. can effectively reduce the loss of the core, improve the energy conversion efficiency, weaken the diffusion of the transformer magnetic field and the concentrated electromagnetic leakage, so that the current and voltage are more stable. In addition, the structure of core can also reduce the electromagnetic leakage loss, further improve the performance and efficiency of the transformer. The choice of silicon steel sheet is based on its high saturation magnetic induction and high permeability characteristics which allows the core to maintain a small size, to maintain good magnetic properties. |  |
2.2 Winding
The resin cast dry transformer produced by our company is divided into: high and low pressure are made of high quality anaerobic aluminum wire winding, glass fiber unfilled resin thin insulation structure (hereinafter referred to as wire winding); The high pressure is wound with high quality anaerobic aluminum wire, and the low pressure is wound with high quality aluminum foil and the two ends of the resin end seal structure (hereinafter referred to as foil winding).
High voltage winding:
The segmented layer winding structure is adopted, and the aluminum conductor and glass fiber material are wound on the core shaft. In winding process, the heat dissipating airway is laid and poured into the winding. All the materials used as insulation and caulk absorb resin, so that you get a very uniform insulation system, and the space outside the conductor is filled with glass fibers. A small amount of plasticizer is added to the resin to obtain a resin with high mechanical strength and elasticity. Turn and layer with small, ground insulation placed in the air.
High voltage winding (wire-wound) :
The spiral winding structure is adopted, and the other conditions are the same as the high voltage winding. It has the characteristics of high mechanical strength and good moisture resistance. Because the wire insulation is impregnated in resin, axial mechanical forces are not transmitted to the fastening structure. The high and low voltage windings are round, and the axial force is evenly distributed.
Low voltage winding (foil wound) :
Aluminum foil together with turn insulation is wound on a foil winding machine to make a winding. When winding, a brace is placed to form a cooling airway. The low voltage winding has low voltage between layers and small magnetic leakage at the end. The leading terminal of the winding is led out by aluminum bar. After the winding is wound, the end is poured with resin (end seal), and a relatively strong winding can be obtained after reshaping. Insulation and aluminum foil bonding as one, can play a role in moisture-proof.
2.3 Final Assembly
| Core Assembly: Assemble and fix the silicon steel sheet core according to the design requirements, ensuring verticality and flatness. Installation: Install the high-voltage and low-voltage resin cast coils, ensuring uniform gaps with the core, and secure the insulating supports. Electrical Connections: Connect high-voltage and low-voltage leads to terminals, ensuring tight and well-insulated connections. Accessory Installation: ● Temperature Control Devices: Install temperature monitoring devices (e.g., thermistors or probes). ● Cooling System: Install auxiliary cooling devices (e.g., fans) if necessary. |  |
03 Testing
1. Insulation test: including insulation resistance test, insulation voltage test and arc resistance test, used to check the insulation performance of the transformer.
2. Voltage ratio test: used to test whether the transformer’s transformer ratio meets the design requirements to ensure the accurate transfer between the output voltage and the input voltage.
3. Voltage resistance test: including voltage resistance test and partial discharge test, which is used to check the voltage resistance and insulation quality of the transformer at rated voltage.
4. Short-circuit impedance test: used to measure the short-circuit impedance of the transformer to determine its current bearing capacity and short-circuit voltage drop.
5. No-load loss and load loss test: used to measure the loss of the transformer under load and no-load conditions to verify its efficiency and performance indicators.
6. Environmental adaptability test: including temperature rise test, wet heat cycle test, etc., used to test the stability and adaptability of the transformer under various environmental conditions.
7. High voltage test: used to test the voltage performance of the transformer under rated voltage and overpressure conditions to ensure its safety and reliability.
8. Variable ratio test: also known as voltage ratio test, used to determine whether the transformer’s transformer ratio meets the design requirements to ensure the accurate transfer between the output voltage and the input voltage.
04 Packing and Shipping
05 Site And Summary
In conclusion, the resin cast dry type transformer, with its outstanding performance, excellent environmental friendliness, and reliable safety, has become an ideal choice for modern power systems. Whether in industrial facilities, commercial buildings, or renewable energy applications, it delivers stable and efficient performance to meet the needs of various scenarios. Choosing a resin cast dry type transformer means choosing an efficient, sustainable, and future-ready power solution!
