Three phase digital ammeter is the terminal of smart grid. In addition to the basic electricity consumption measurement function of traditional energy meters, it also has intelligent functions such as electricity information storage, bidirectional multiple rate measurement function, user end control function, bidirectional data communication function of multiple data transmission modes, and anti-theft function to adapt to the use of smart grid and new energy. Three phase digital ammeter represents the development direction of future energy-saving smart grid user terminals.

Reducing the power consumption of three-phase digital ammeters and improving their operational efficiency has become an important aspect of current smart meters. Switching power supplies are different from other components in smart meters. Large scale and standardized production may improve quality, reduce production costs, and optimize production processes. Although switch mode power supplies for digital ammeters have received attention, there are still many problems in the development of switch mode power supplies in China, such as a lack of basic theory, insufficient industrial level to meet demand, and immature production processes. In addition, the phenomenon of meter explosion caused by switching power supplies has always been one of the important reasons that troubles and hinders its widespread application. Other reasons include the reliability of long-term work. At present, traditional power frequency transformers are still the main power source for intelligent digital ammeters in China, while some foreign products have gradually adopted switch mode power supplies. The main reason is that with the strengthening of the ammeter function, the power supply requirements have increased, making it difficult for power frequency transformers to handle. Meanwhile, considering installation and transportation costs, switch mode power supplies will have significant advantages.