Product Introduction:

The S20-M-10 (10-35KV) series transformers are Class II energy-efficient oil-immersed distribution transformers as defined by Chinese National Standard (GB 20052-2020/2024). The main advantage is the drastic reduction in operating losses due to material upgrades and design optimisation over conventional models like the S13. Now they are the mainstream energy-saving product for power grid construction. The purchase cost is a bit higher at first, but the lower electricity costs due to the losses mean you will recoup the cost within a few years, so the life-cycle cost is lower. 

Application scenarios ：

This transformer is widely used in power transmission and distribution system of 50Hz frequency, rated voltage of 10kV and below, and is especially suitable for: 

1. Residential and commercial power distribution with emphasis on low noise and energy saving; 

2. Power distribution for factories, including short-circuit withstand capability and stability; 

3. Industrial parks, logistics parks, etc., centralised power supply, focusing on load fluctuation adaptability and operation and maintenance efficiency.

Product Characteristics：

1.High quality core:

mainly using high permeability, low loss, high-grade cold-rolled grain-oriented silicon steel sheets (such as 23ZH80), and optimising the lamination process (such as 45° full-angle joints) to reduce hysteresis and eddy current loss.

2.High quality windings: 

The windings of high voltage windings are generally oxygen-free copper wire, and the windings of low voltage windings are generally copper foil windings, which can reduce the resistance and additional loss, and improve the short circuit withstand capability.

3.Sealed heat dissipation:

The corrugated oil tank structure of the common models (such as S20-M) is fully sealed and isolated from the air and moisture, which delays the ageing of the insulating oil and generally there is no need for core lifting maintenance, thus suitable for unattended outdoor scenarios.

4.Low noise:

The lower no-load current and optimised core result in operating noise that is generally lower than older models of the same capacity, making it more suitable for sensitive areas such as residential areas.

Technical Parameter

Structure and working principle of oil-immersed transformer:

Oil immersed transformers are similar in construction to the regular transformers. They are a class of transformers classified by the nature of the core insulation. Therefore, they have the important features of oil-immersed coils, which decreases the thermal effect on the inner parts. 

The three basic components of an oil-immersed transformer are the core, windings and bushings. The core provides a path for the magnetic flux. The windings create the magnetic field. They are made of conductor coils wound on the core, insulated by cardboard diaphragms and shielding layers. As the voltage goes up, the winding insulation gets thicker. Bushings connect to the transformer winding for the substation. 

Transformers are filled with oil and used in substations or power distribution . The core and coils are submerged in oil, which acts as both a coolant and an insulator. Convection causes the oil to flow through the oil pipes in the coils, around the coil and core assemblies. The oil is cooled externally by the tank in small power transformers and by an air-cooled radiator in large power transformers. 

Function of Oil Immersed Transformers:

1. Oil-immersed transformers are installed on the ground, on a base or on a pole, so they are suitable for outdoor environment. They are efficient in a variety of applications such as power transmission and distribution networks, renewable energy generation and small scale industrial applications.

2. Oil-immersed transformers are of large capacity, so they save a large amount of electricity, reduce the power loss, save energy and reduce the user costs. Moreover, the transformer’s oil cools down the internal iron core. It enhances the durability and electrical behaviour of the transformer. 

Usual operating conditions:

1. Ambient temperature up to +40°C

2. Minimum ambient temperature ≥ -25 °C

3. Standard installation altitude up to 1000m

4. Special conditions require derating.