Research On FTU Of 10kV Railway Power Supply Line

Traditional railway management has some drawbacks that already restrained from railway transportation developed toward at a high speed, high density seriously. Railway supply power urgently demands a security and reliance to realize monitoring function of railway load switches. Namely, remote control"three distant"function and the technologies of functions of far distant management. At present, a kind of circuit automatic technology with above-mentioned functions has already been developed progressively rapidly, but it can't apply to railway distribution automation. The feeder terminal unit (FTU) is the fundamental control of the distribution automation, so it is more necessary to research on FTU of the railway supply power.In this paper we explain our own understanding of railway supply power feeder automation after consulting various kinds of feeder automation schemes. On the basis of comparing and consulting the domestic and international similar apparatus, we design a new kind of FTU based on 80C196KC. Our FTU communicates with Substation Terminal Unit(STU) to form a net and collect the three phase current and zero sequence current of load switches to monitor feeder normal running. At the same time, our FTU can get over that the fault feeder was cut off by breaker in the past. The old approach will bring some bad influence in reclosing the load switches several times and impacting switches, feeder equipments and so on.In this paper we analyse the function of FTU, including measuring, controlling, protecting, communication, etc. at first, and then we confirm the hardware frame structure of the device and systematic scheme of software. On the hardware design we provide the operation principle of the main function module and design content in detail, including Analog Inputing, Digital Inputing and Outputing, Wacthdog, Communication Interface and Man-machine Interface, etc. On the software design we adopt assembler language to program and blocking ideas, divide the systematic task module concretely, and give the different PRI according to the nature of the task. This not only meets the requisition for real-time character of the railway power system but also raises the flexibility of the software system greatly. The task module designed mainly includes: data acquiring, data processing(FFT), protection and communication. We also design EMC(Electromagnetic Compatibility) to impove FTU's reliability. Laboratory simulations testify that if FTU connects with STU to form a net, it can reliably locate and isolate single phase grounding fault when zero sequence current passes 0.1A, and that when it occurs short circuit fault between phases, FTU will send disconnection signal which is set by time and current in advance. So it can obtain aims that non-fault section doesn't power cut and the fault section is isolated.