(1) Core manufacturing technology
Enterprises mainly improve core production technology by improving their own shearing equipment. Currently, core manufacturing technology has the following changes: ① The core column adopts the embedded yoke process. Compared with the conventional process, it can save a lot of core column stacking time and improve the core stacking quality. This process is suitable for the automated production of distribution transformer cores. ② The application of multi-stage joint cores. In recent years, in order to reduce the no-load loss at the core joints, the traditional single joints have been gradually changed to multi-stage joints.
(2) Winding manufacturing technology
In the 1990s, the winding assembly process was invented. At present, this process has gradually been favored by various transformer manufacturers and has been rapidly promoted.
(3) Insulation processing technology
In the 1980s, with the increase in product voltage level and capacity and the increase in test items, insulation processing gradually separated from metal processing. The existing gantry CNC machining center has achieved full automation of insulation processing.
(4) Insulation drying and oil treatment technology
Oil-immersed transformers use oil-paper insulation structure. Its core process is the drying treatment of insulating materials and the vacuum dehydration of transformers. Gas phase drying: In the mid-1980s, Chinese transformer factories took the lead in introducing gas phase drying equipment from Switzerland. In recent years, new products such as built-in kerosene evaporators have been developed. Compared with traditional external evaporators, both have their own advantages and disadvantages. Transformer oil treatment: In the 1980s, with the introduction of advanced oil filtration equipment from Europe and the United States, China's oil purification technology has made great progress. Most companies have adopted the advanced vacuum spray oil purification method, which has significant impurity removal and dehydration effects.
(5) Energy-saving technology
In terms of the development history of transformer energy-saving technology, transformers have gone through the replacement process of several series such as S6, S7, S9 and S11. At present, S9 energy-saving products have become the mainstream of the market, and the market size of S11 energy-saving products is growing. In the process of promoting S11, the sales price of S11 is 14.2% higher than that of S9 on average, so price is still the main factor affecting the popularization and promotion of S11 transformers.