Design And Development Of Wide Range Ultrasonic Cable Altimeter

UHV power transmission lines are necessary support for the development of clean energy in China and will constitute a large-capacity,long-distance energy transmission channel in China.In recent years,partial discharge caused by the high-voltage overhead cable’s height to the ground and the distance between phases has occurred from time to time,seriously affecting the safe operation of the power system and causing huge economic losses.Therefore,it is imperative to develop mature and reliable ultrasonic cable height detection technology.In the field of industrial applications,the detection distance of existing ultrasonic sensor devices in the market does not exceed 10 meters,and it is unable to meet the requirements for wide-range detection of ultrasonic cable height measurement.In this paper,in view of the problems existing in high-speed overhead cable distance detection technology at home and abroad,in-depth research has been conducted on hardware circuit design,function software development,ultrasonic elevation algorithm,and shell structure design for improving the ultrasonic height detection range and the detector’s portability,thus developing a portable and wide-range ultrasonic cable altimeter.Firstly,in terms of hardware circuit design,the propagation characteristics of ultrasonic waves in air media were studied,and the ultrasonic cable altimeter system architecture was designed.This article uses STM32 as a micro-controller using TCF single-shot ultrasonic transducer and 9V battery.Ultrasonic signal excitation module uses pulse transformer to boost drive voltage.Ultrasonic signal conditioning module mainly implements bandpass filtering and logarithmic amplification.In addition,the temperature sensor MF58 collects the ambient temperature and corrects the speed of sound.Serial communication circuit guarantees normal communication between upper computer and lower computer.Secondly,in terms of functional software development,the software programming implementation and wide range ultrasonic altimetry algorithm for each module of the system were studied in detail.The lower computer software is based on the C language of the ARM library function and is responsible for the functions of driving pulse sending,data acquisition,temperature acquisition,sound speed correction,distance calculation,and data upload.The upper computer adopts C#programming language to establish a high-voltage cable height measurement database and realize data display,data analysis,RS232-serial communication,and other functions.On the basis of comparative analysis of traditional thresholding method and cross-correlation method,an ultrasonic height-delay estimation method based on vibration model is proposed.The ultrasonic echo signal is identified according to the rising edge characteristic of the ultrasonic transducer vibration time domain waveform and the ultrasonic echo starting position is estimated therefrom.Finally,in terms of mechanical structure design,an ultrasonic height enhancer is designed for the problem of difficult detection of echo signals due to the dispersion and attenuation of ultrasonic energy in long-distance detection of ultrasonic sensors.According to the acoustic theory,the ultrasonic height enhancer can improve the radiation efficiency by improving the impedance matching.The Bessel function was used to analyze the ultrasonic height enhancer to make the sound source directivity sharper and the energy more concentrated,and related simulation calculations and design were performed.The experimental study verifies that the ultrasonic height enhancer can significantly improve the detection distance of the ultrasonic sensor.This paper innovatively proposes the rotary probe structure design and uses UG software to establish a three-dimensional mechanical model,realizing the multi-azimuth distance information detection of the ultrasonic cable altimeter and expanding its scope of use.Ultrasonic testing is the most effective,safest and fastest technical measure for overhead cable height measurement.After test verification,the large-scale portable ultrasonic cable altimeter successfully developed in this paper can accurately,stably,reliably detect the distance from a cable with a distance of 30 meters in real time.It is of great significance to reduce the work intensity of operation and maintenance personnel,improving work efficiency and ensuring the safe operation of high-voltage cables.