Research On Inclination Monitoring Of Transmission Tower Based On Fiber Bragg Grating Sensing

Transmission line tower Tilt is one of the important influencing factors that affect the safe and stable operation of power grid,and the land topography and geological instability will lead to the tilt of the tower,and even the occurrence of disconnection and inverted tower accidents,resulting in a large area of power outage of transmission lines,thus bringing huge economic losses to the country and the people,Has seriously affected the safe and stable operation of the power grid.On-line monitoring of the severity of transmission line tower tilt can reflect the status and development trend of the tower,so that problems can be detected in time to reduce or avoid the occurrence of transmission accidents.In recent years,Yunnan power grid investment and construction of transmission line tower tilt on-line monitoring system,in order to provide data support for the prevention of transmission line Tower Inverted tower,this paper takes a 110 kV glass tower in Yunnan as the research object,mainly carried out the following research work:(1)Through the side sinking,non-uniform settlement of the tower and the finite element simulation experiment when the unbalanced tension is obtained,the transverse and linear inclination of the tower is changed in the 0-1.6° range when the effect of lateral sinking,non-uniform settlement or unbalanced tension occurs in the tower tilt.Through the finite element simulation experiment,the selected fiber grating biaxial inclination sensor should have high sensitivity in the-10°-10° range,and the minimum recognition angle should be less than 0.1°.The mathematical model of tower tilt of transmission line is constructed,which shows that the use of fiber grating biaxial inclination sensor can effectively monitor the change of inclination at the top of the tower and the change of inclination at the waist of the tower.(2)The basic principle of fiber Bragg grating sensor is studied,and the calibration experiment of fiber Bragg grating biaxial inclination sensor is carried out,and the linearity of fiber Bragg grating biaxial inclination sensor is 0.196%,the sensitivity is 61.86pm/°,the minimum angle can be identified is 0.05°,the return error is 3.72%,and the repeatability error is 3.2%,the maximum deformation of the fiber grating is 0.635 nm,the precision of the fiber demodulator is ±2pm,and the resolution is 1pm.The performance parameters of fiber Bragg grating inclination sensor meet the performance requirements and can be used for on-line monitoring of the tilt of the actual transmission line tower.(3)Two Fiber Bragg grating Two-axis inclination transmitter is installed on the actual transmission line tower to be used for real-time monitoring of the inclination of the tower.Collecting and collating the monitoring data of the tower tilt of a 110 kV transmission line in Yunnan power grid,the tilt angle of the top tower is mainly concentrated in the 0°~+1.2° range,and the angle of the waist tilt of the tower is mainly concentrated in the 0°~+1° range.The alignment tilt angle of the rod tower top and the waist is not equal,and the tilt of the tower may be caused by the instantaneous tilt of the tower in this time period and the swinging of the tower in a small period of time.Judging from the average angle of the top of each month and the mean of the waist inclination of the tower,the tilt angle of the top of the tower is about 1.3-1.8 times times that of the tower waist tilt angle,and the pole from the tower waist to the top of the tower has a stress deformation.