Study And Development Of Distribution Transformer Terminal Unit

This paper develops a terminal Unit for supervision and control of distribution transformer in Distribution Automation, and fulfills the design, development and debugging.First, from the viewpoint of safe operation in electrical distribution system, the importance of developing Transformer Terminal Unit is pointed out, and the status in quo of technology, the direction of progress, the practical demand and fundamentality of Transformer Terminal Unit in Distribution Automation are analyzed. The function of equipment and technical specification that meet the demand of practical duty are indicated. Second, the current algorithm is analyzed and compared in detail and the schemes which not only meets the demand of the hardware but also decreases investment, ensures precision and simplifies program is picked out. Consequently quasi-synchronous sampling is ascertained. Through error analysis of quasi-synchronous sampling, a method of improving precision that begins to sample from ?45?after zero point is put forward. At the same time, the method of disposal phase shift of CT by compensation is introduced. Then the analysis and statistic ofelectrical power quality, the control scheme and compensating amount of capacitor for reactive power compensation are analyzed respectively. And in the paper, the control with A/Y and the switch with AC contactor and solid state switch is valid measure not only for improving operate level economically and amending electrical power quality but also for avoiding of replacing switch frequently and decrease economic loss. Finally, the electro-circuit of hardware and flow chart of software is designed respectively.The test proves that the new developed Transformer Terminal Unit has higher metrical veracity, reasonable control scheme and reliable performance, and the original object is attained.