Design And Realization Of CT-powered Measurement And Control Device

Along with the rapid development of the China Economy, the society has made the higher and higher requirement of the Electricity reliability. It gets more and more urgent for us to make effective and wide supervisory for the Electricity Net to improve the management, quality and the reliability of the power supply. Traditional supervisory device needs PT or battery, but the characteristics of the PT are huge size and high cost, and what’s worse is that the battery has the problem of less electricity and less lifetime. So exploring a new method of the power supply has very significant meaning for the wide apply of the measuring and controlling device without any doubt.It has becoming a trend to get power from CT in the measuring and controlling device in the electrical power system because it has the characteristics of less cost, small size, long lifetime and safe and reliability which can give continuous and sufficient electricity as long as there is big enough electricity in the wire. But there are also some other characteristics or disadvantage such as how to release excess electricity when the electricity in the wire is too big and how to get electricity as much as possible to give sufficient electricity to make the device continuously work when the electricity in the wire is as little as possible.The measuring and controlling device which get electricity from CT will get wide use and has wide market for its less cost, wide applicability and convenient installing and reforming.The first chapter of this paper first introduces the history and the current situation of distribution automation technology, analyzes the development trend of distribution automation technology, as well as the classification of distribution automation device, and then analyzes the shortcomings of the traditional measurement and control device PT or transformer power supply, points out the advantages and disadvantages of measurement and control device CT-powered, introduces in detail the function the characteristics and application prospect of measurement and control device of CT power supply, and then from4aspects of hardware design, device selection, structure design and software design introduced the design points distribution how measuring and control device and functional requirements are analyzed.The second chapter of this paper introduces in detail the transformer and the work principle of CT, the power grid load characteristics, CT electric problems and solutions, on the device design, performance characteristics, the control circuit of the process are described in detail, and the characteristics of the control circuit is analyzed.The third chapter introduces the circuit principle of automatic measurement and control equipment of power distribution system composition and each function plug-ins, the working process of a remote control circuit, telecommunication circuit and485communication circuit were described in detail.The fourth chapter analyzes several problems we should pay attention to the design of automatic measure and control device, the main engineering design, reliability design, security design and scal ability design.The last chapter, the author has carried on the summary to this design, and introduces the focus of the work to be performed after.