Overload capacity of dry-type transformers of different capacities

The overload capacity of a dry-type transformer is related to the ambient temperature, the load condition before overload (initial load), the insulation and heat dissipation of the transformer, and the heating time constant. If necessary, the overload curve of the dry-type transformer can be obtained from the manufacturer.

my country's resin-insulated dry-type transformer has reached 10,000MVA, becoming one of the countries with the largest dry-type transformer capacity in the world. With the promotion and application of SC(B)9 series with low noise (distribution transformer noise below 2500kVA has been controlled within 50dB) and energy saving (no-load loss reduced by 25%), the performance indicators and manufacturing of dry-type transformers in my country The technology has reached the world's advanced level. 

With the popularization and application of dry-type transformers, its manufacturing technology has also achieved considerable development. It can be predicted that the future dry-type transformers will be further developed in the following aspects.

1. Multifunctional combination: From a single transformer to a multifunctional combined transformer with air cooling, protective casing, temperature computer interface, zero sequence transformer, power metering, enclosed busbar and side outlet.

2. Multi-field development: From distribution transformers to special transformers and multi-purpose fields such as power station auxiliary transformers, excitation transformers, subway traction rectifier transformers, high-current electric furnace transformers, nuclear power plants, marine and oil production platforms. Among them, dry-type traction transformers used in urban subways and rail transit have three voltage levels of 10, 20 and 35kV, and capacities of 800, 2500 and 3300kVA. In order to reduce harmonic pollution, the rectification has been developed from 12 pulses to 24 pulses. Rectification: The world's largest excitation transformer for the world's largest 840,000kW generator in the Three Gorges of the Yangtze River has been successfully developed by Shunte Factory and passed the national inspection and acceptance.

3. Energy saving and low noise: With the introduction of new low-consumption silicon steel sheets, foil winding structures, stepped iron core joints, environmental protection requirements, in-depth noise research, and the introduction of new materials, new processes, and new technologies such as computer optimization design , Will make future dry-type transformers more energy-saving and quieter.

4. Environmental protection characteristics certification: Based on the European standard HD464, carry out research and research on the characteristics of weather resistance (C0, C1, C2), environment resistance (E0, E1, E2) and fire resistance (F0, F1, F2) of dry-type transformers based on the European standard HD464 Certification.

5. High reliability: Improving product quality and reliability will be people's unremitting pursuit.

6. Large capacity: from 50～2500kVA distribution transformer-based dry-type transformers to 10000～20000kVA/35kV power transformers, as the urban power load continues to increase, urban network regional substations are getting deeper and deeper into the city center Districts, residential communities, large factories and mines and other load centers, 35kV large-capacity power supply transformers for community centers will be widely used.