Design And Implementation Of SCADA System For Distribution Network Feeder Automation

Distribution network feeder automation SC ADA system is an automation system for data acquisition and control based on communication,computer and control technology,which can monitor and control remote equipment terminals,switch capacitors,and shift transformers.It can reduce duration and scope of power outage with the help of the functions of fault isolation and restoration of power transmission.In a word,its realization plays an irreplaceable role in improving the power supply quality,reliability and safe operation of distribution network.This paper conducts relevant researches on the design and implementation of distribution network feeder automation SC AD A system.At first,it reviews the domestic and overseas development status of distribution network feeder automation and summarizes the significance of realizing the feeder automation.Then,it introduces the function and installation of the monitoring object of feeder automation,analyzes its real-time requirements,and expounds the working principle of fault isolation and restoration of power transmission function.The construction of communication network is one of the key contents to realize feeder automation SCADA system in distribution network.This paper analyzes the characteristics and communication mode of feeder automation communication network in detail,designs a highly reliable fiber self-healing ring network,and explain how to adjust and maintain the network structure in actual use.Optical transceiver must be used together in cooperation with the use of optical carrier networking.This paper analyzes the advantages and disadvantages of the networking mode in cooperation with different optical transceivers with different functions.Based on the characteristics of SCADA system with many data collection points and wide coverage,SCADA system is divided into three layers:master station,sub-station and terminal.The master station is the system server station and operator workstation;the sub-station is the transfer station,which is the system data acquisition and processing;the terminal is the equipment and monitoring terminal.A master station can have several substations.This design not only meets the characteristics of feeder automation system with many points and wide coverage,but also improves the communication speed.According to the functions and real-time requirements of each station,the communication media suitable for each station are analyzed.The sub-station is far away from the master station,therefore,the single-mode optical fiber channel can be used.Considering the real time and financial conditions,the priority order of communication media between sub-stations and terminal is multi-mode optical cable,cable and power carrier,ultra-short wave radio.TTU and collector have few requirement for the real-time performance,therefore,it can be transmitted through the nearby FTU,and shielded twisted-pair or low-voltage carrier can be adopted as the communication media.Based on the fact that SCADA system is the basic level of feeder automation,this paper studies the basic functions of SCADA system needed to be fulfilled,its data exchange mode with peripheral system,and the access method of database interface.The front-end processor is the core part of the SCADA system,which is not only responsible for contacting the upper control center,but also responsible for the lower equipment.A flexible,convenient and advanced design concept of the front-end processor was put forward in this paper.One of the important functions of SCADA system is fault isolation and restoration of power transmission.At present,only two protocols of DNP3.0 and IEC-101 are applicable.The former is American standard and the latter is the IEC standard.The rule and realization method of software of IEC 101 are analyzed in this paper.Finally,the running conditions of the distribution network feeder automation SCADA system used in Yangzhou project is introduced and it proves that after testing,all the indexes meet or exceed the relevant requirements made by Jiangsu Electric Power Company for feeder automation.