As the core equipment for energy conversion and transmission in the power system, large transformers are directly related to the economy, reliability, and intelligence level of the entire power grid. The level of technological development often represents a country's power industry strength.
Core application scenarios
● Main power grid hub
In ultra-high voltage transmission projects, transformers of 500kV and above bear the responsibility of cross regional transmission. Taking the "West East Power Transmission" strategic project in China as an example, the 1000MVA high-capacity converter transformer used, through optimized magnetic circuit design and the use of ultra-low loss oriented silicon steel sheets, strictly controls the no-load loss rate below 0.18%, which can reduce energy loss by about 18 million kilowatt hours per year. These types of transformers are usually equipped with online oil chromatography monitoring systems to detect changes in dissolved gas content in real time to prevent malfunctions.
● New energy grid connection node
In response to the special environment of offshore wind power, the 220kV step-up transformer innovatively adopts multi-layer composite anti-corrosion coating technology, with a protection level of C5-M according to ISO 12944 standard (harsh marine environment), and can withstand salt spray corrosion for more than 25 years. Equipped with on load voltage regulating switches, it can automatically adapt to voltage fluctuations caused by changes in wind speed, ensuring the stability of the power grid.
● Industrial heart
The rectifier transformer dedicated to the metallurgical industry adopts a patented three winding structure design, which improves the suppression ability of characteristic harmonics (such as 5th and 7th order) by 40% through the principle of magnetic potential balance. Combined with a water-cooled cooling system, it can meet the short-term overload demand of up to 150% during continuous production of electric arc furnaces. The application case of a certain steel base shows that this technology reduces the electricity consumption per ton of steel by about 12kWh.
Technological Evolution Trends
● Material Revolution: The promotion and application of amorphous alloy iron cores have reduced no-load losses by 70%. According to Global Market Insights, the related market size is expected to exceed $2 billion by 2024. Hitachi Energy's latest research and development of a three-dimensional coiled iron core transformer can control the noise level below 55 decibels, making it particularly suitable for urban substations.
● Digital Twin: ABB's intelligent transformer is equipped with over 200 fiber optic sensors, and through machine learning algorithms, the prediction error of winding hot spot temperature is ≤ 2 ℃, providing a 3-month advance warning of potential faults. The State Grid demonstration project shows that this technology can reduce maintenance costs by 30%.
● Environmental transformation: Transformers using natural ester insulating oil have a biodegradation rate that has increased from 35% of traditional mineral oil to 98%, and the ignition point has been raised to 360 ℃. Europe has legislated to require all newly built substations to use environmentally friendly oil products by 2026.
● Modular design: The 750kV detachable transformer developed by Siemens adopts the transportation scheme of "breaking the whole into parts", and the maximum weight of a single piece decreases from 380 tons to 190 tons, which shortens the construction period of a hydropower station in the Yunnan-Guizhou Plateau from 24 months to 10 months.
Future challenges
In the context of building a new power system, the industry urgently needs to break through two technological bottlenecks: one is the control of local discharge of ± 800kV DC transformers (which needs to be stable<5pC), with the best record in domestic laboratories currently being 7pC; the other is the localization of high-end oriented silicon steel sheets, with a current import dependency of up to 80%. Baowu Group's 0.18mm thin specification product is expected to break the foreign monopoly. In addition, the EU's newly issued ecological design regulation for transformers (EU 2023/814) imposes strict requirements on carbon emissions throughout the entire lifecycle, which will force the entire industry to accelerate green technology innovation.