Research Of Application Design On Feeder Terminal Unit Of Distribution Network Based On DSP

With the rapid development of power network, the reliability of distribution network has become more and more important. Carrying distribution automation into effect is an inevitable trend of power system modernization. Nowadays, feeder automation based on Feeder Terminal Unit (FTU) is a mainly used method in distribution automation in our country. With the help of FTU and communication network, remotely real-time monitor for the states of sectional switches can be achieved by distribution control center. When the fault occurs, the position can be identified quickly and the fault section will be isolated by FTU soon. Meanwhile, non-fault section will recover power supply. In this way, the reliability is improved. FTU has aroused hot R&D in distribution automation. The standard of power industry requires high performance of it.This dissertation specifies the function and performance requirements of FTU, analyses and compares the protection and measurement algorithms of distribution apparatus and the implementations of feeder terminal apparatus, analyses the advantages of applying digital signal processor in distribution apparatus based on the R&D experience that we got home and abroad. After careful comparison of various schemes of FTU, one design scheme using DSP as its CPU is put forward. The main structure of the device, the performance of the microprocessor, the design of analog inputs, the A/D sampling method and communication module are discussed in detail. The design schemes of frequency detecting, switch-in, switch-out, data storage module and clock module etc are also provided in this paper.The software system follows the modular and up-to-down design principles. The general frame of software, including main program and the A/D sampling interrupt service routine, are specified in detail. The thesis summarizes several attentive aspects-meet in software designing and debugging. These are helpful to optimize the software and improve the reliability of software. It provides a better way to meet the requirements of real-time monitoring along with better measuring accuracy.The device introduced in this paper puts together such functions as measure, communication, protection, control and etc. It can provide the parameters of electrical network such as voltage, current, power, frequency and so on. The device has passed all test items, and also qualified in China Electric Power Research Institute on June 2004.FTU has been applying in Ma'anshan power supply bureau, Anhui province since April 2003. Its performance is pretty well. It achieves prospective target and helps a lot to realize feeder automation of the distribution network. Meanwhile, it is highly praised by Ma'anshan power supply bureau and has passed all correlative deliberations. Practice shows that the FTU described in this paper is a kind of distribution terminal apparatus that satisfies the requirement of power distribution industry very well. The solution this paper discussed is valuable for better reliability of distribution network on engineering application and technology reference.