Research On Single-Phase Power Distribution Transformer Terminal Unit

China’s low-voltage distribution system has been widely used three-phase distribution mode, which has problems of high line losses, low voltage quality and high distribution transformer losses. In the new situation of State Grid’s making great efforts to the development of energy saving projects and to improve the voltage quality, single-phase distribution model began to get promotion. To solve the problem of distribution transformers single-phase power distribution system monitoring, this paper has a research on the Transformer Terminal Units (TTU). And a kind of single-phase Transformer Terminal Unit (TTU of single phase) is designed in this paper, which can have a good monitoring of single-phase distribution transformer and guarantee the reliable operation of the distribution system.This paper introduces the research background, analysis the using principle of single-phase distribution transformers in single-phase power distribution system, has a research on the concept and development of distribution automation system and analysis the effect of TTU in it; And then, through market research and analysis, combining with the research on TTU at home and abroad, a design scheme of single-phase distribution transformer operation condition monitoring terminal (single-phase TTU) is put forward.Firstly, through the analysis on the functional requirements of single-phase TTU, the overall system design is put forward. Selecting dsPIC30F4011which has a fast operation,a full-featured and a good performance as the MCU, to guarantee the stability and fast of the overall system functions; Using RN8209which is a high-performance and dedicated energy measurement chip for data acquisition and processing, improving the accuracy of the data; Basing on the selected controller and other peripheral devices, the hardware design is completed including the main controller module, data acquisition and processing module, switch input and output modules, human-computer interface module, clock module, communication module and power module. A full consideration on filtering and anti-jamming is given when designing the hardware to improve the stability of system. And then completing the system modular software design using the software of MPLAB, to improve the portability and scalability of system; Finally, the overall combination of hardware and software is completed, and the function of system is also achieved through debugging, and each module functions are tested under the laboratory conditions. This paper can achieve these functions including data acquisition and storage, bidirectional energy metering, local real-time monitoring and remote monitoring. Compared with similar products, single-phase TTU shows some advantages in aspects of energy consumption, interference immunity, the precision and speed, application potential and cost-effective. With the advantages of high precision, high stability, good real-time and cost performance, it can entirely meet the needs of single-phase distribution system and has broad market prospects.