Research On Base Displacement Monitoring Technology Of Power Transmission Tower

With the development of China’s electricity,the demand for electricity from all walks of life is increasing,the number of electricity transmission tower is increasing too.Due to the topography of our country,electricity transmission towers are often built in mountainous areas,above the tunnel,coal mine goaf.The tower base serves as the foundation of the entire tower,easily affected by the construction of the mountains below,landslides,strong winds and snow.These effects will cause uneven forces on the tower base,resulting in displacement and tilt.when the displacement and tilt of the tower foundation exceeds its specified limit,it will also cause the entire tower to collapse.At present,manual inspection is mostly used for tower foundation monitoring,which takes a long time and has low efficiency and is not easy to carry out in harsh environment.Therefore,it is necessary to find an efficient monitoring method for tower foundation displacement and tilt.This thesis uses a GPS-based dual-frequency carrier phase difference method to monitor the displacement and tilt of the tower base.By installing GPS monitoring equipment on the tower base,forms relative positioning with the nearby reference station.The antennas of the monitoring station and the base station receive GPS L1 and L2 carrier signal data at the same time.Then the data is sent back to the data processing center,and the data processing center calculates the data through MATLAB software to obtain the three-dimensional coordinates of the monitoring station.The calculation process is as follows:(1)decode the received binary data according to the UBX protocol,Calculate the decoded data to obtain information such as satellite position,pseudorange,carrier phase,etc;(2)use the cycle slip detection method to detect the carrier phase data to determine whether the original data has cycle slips.Double difference the carrier phase data without cycle slip between stations and satellites,combine the double difference of the two frequencies through the wide lane combination method.The LAMBDA algorithm is used to solve the ambiguity,and the three-dimensional position coordinates of the monitoring points are obtained;(3)the coordinates are smoothed by Kalman filter algorithm.Comparing the calculated coordinates with the normal coordinates,the displacement and tilt of the tower foundation can be obtained.This thesis verifies the effectiveness of this method through experiments on the basis of theoretical research.first,the Kalman filtering experiment is verified,and the results show that the filtering method can effectively filter the coordinate data;then,the distance between different reference stations is verified.The influence of the measurement result shows that the change of the distance between the base station and monitoring station at a short distance basically has no effect on the measurement result;the horizontal displacement,vertical displacement and inclination of the tower foundation in an open environment and a sheltered environment are simulated,The results show that in the measured open environment,the maximum deviation between the calculated value of the simulated horizontal displacement and the true value is 0.54 cm,the maximum deviation between the calculated value of vertical displacement and the true value is 0.61 cm,and the maximum deviation between the calculated value of tilt and the true value is 0.095°.The maximum deviation between the calculated horizontal displacement and the true value under the measured sheltered environment is 0.76 cm,the maximum deviation between the calculated vertical displacement and the true value is 0.81 cm,and the maximum deviation between the calculated tilt and the true value is 0.118°.