Monitoring And Analysis Research Of Overhead Transmission Lines Crossing

Overhead transmission line is the transfer channel of electric power, and it is an important part of the power system, its reliability is directly related to the stability of economic development. However, the safe operation of the transmission line has permanently affected by crossing. The distance will be changed between high voltage transmission line and crossed object when subjected to strong winds,subsidence,tree growth,temperature variation,wire aging and other factors. If the crossing distance is too small, electric power accident will occur due to discharge between transmission line and crossed object.Overhead transmission line, the environment of which is harsh, is usually built in the wild. Manual inspection can only check crossing trouble regularly; it cannot ensure the safety and reliability of the line. According to the survey, the measurement, recording and analysis of crossing parameters are accomplished by manual, the efficiency and precision of which is very low. Based on the State Grid in Shanxi Province Yangquan power supply company project "The Verifying and Analysis Research of Overhead Transmission Lines Crossing", the paper implements a crossing monitoring and analysis system, by using advanced sensor technology, wireless network communication technology and computer technology.Around actual demand of crossing, this paper mainly studies the following main contents:(1) Based on the catenary equation, mathematical model of transmission line is set up when there is wind or not. The calculating formula of sag and crossing distance are given.(2) The mathematical expression of transmission line is associated with its dip angle. Considering measure error of traditional single tilt is very large, a crossing monitoring method for multi-tilt measurement is proposed.(3) A “Star + Remote” wireless network is built, using the technology of RF wireless network and GPRS communication.(4) The hardware design of the repeater and sensor node is completed. The tilt circuit was designed, among which the source of error is analyzed and modified method is given. According to the datasheet, a detailed analysis of the power consumption of each circuit is made.(5) Using the program architecture of “Task polling”, the program design of the repeater and sensor node is proposed.(6) With programming theory, this paper completed the design of the on-line monitoring software and the crossing calculation and analysis software.(7) The feasibility and reliability of the whole system are verified by the simulation experiment.