Hard Ware Design of Transformer Terminal Unit (TTU) Based on Substation Automation

Abstract

The distribution transformer monitoring system is composed of Transformer Terminal Unit (TTU), GPRS wireless communication network and master station. TTU is installed in the transformer, which mainly accomplishes data collection, analysis and record, pops up alarm information in time when the transformer has abnormal events, receives the command from the master station and implements it. GPRS wireless communication network is the bridge of data transmission between the master station and transformers. Master station receives the real-time data of transformers through GPRS wireless communication network, implements further data processing and saving, consequently issues control command. Therefore the system can achieve a comprehensive monitoring and control for distribution transformers. At the same time, it can provide users with a visual interface and let dispatches obtain monitoring performance of far transformers in time for never leaving home. Choosing an appropriate device should also be considered when designing and low power consumption components. From replacement and easy maintenance considerations and reliability, the controller part is independent chassis equipment. We focus on the selection of hard ware component and corresponding hardware design of TTU, designing a high reliability and multifunction TTU which meet the application requirements is an urgent need for substation automation. This paper presents a new hardware design for TTU; the design is composed of seven main parts with its own components which include: conditioning circuit of A-Phase voltage and conditioning circuit of A-Phase current, Circuit diagram of switch input. power supply regulator, Multiplexer switch (AD7506), Clock circuit design output switch control circuit and Communication interface circuit.