A Study On The Distribution Terminal Based On The LonWorks Technology

In our country, distribution automation system generally consists of master station, sub-station and distribution terminal. The distribution terminal is one of the key parts of the distribution automation system, implements data acquisition and control of the 10KV feeder line and the switch. One kind of distribution terminal is developed by the thesis with the function of analog signal acquisition, digital signal acquisition, electrical parameter computation, switch control and communication, which satisfies the county distribution network needs.The thesis researched the LonWorks technology deeply, considered the function of the distribution terminal, implemented the new design scheme based on the LonWorks intelligent node technology. The new scheme used the neuron 3150 chip directly to reach A/D transformation by the way of V/F, applied fixed constant min-square-filter algorithm in electrical parameter computation, which could make it possible for measuring,controlling,communicating on one Neuron 3150 chip.The thesis introduced the whole design scheme, particularly the hardware and the software design scheme of the device. The hardware circuit of the device was presented, which included the analog processing unit, the digital input unit, the digital output unit, the power source module, external memory expanded circuit of 3150 chips, the transceiver and the additional circuit. The software of the device was composed of the main program module, the analog signal acquisition module, the switch signal acquisition module, and the data transmission module. The diagram of software was also proposed.The distribution terminal device developed by the thesis has the feature of the simple structure,the full function and the low price. At present, the prototype has been completed, and the experimental results on a 10KV feeder show that the measuring accuracy meets the design requirements.