Research On Comprehensive Maintenance And Detection System Of Power Cable For Internet Of Thing

With the continuous advancement of urbanization,buried power cables have been widely used in urban areas due to their advantages of saving space,improving urban environment and reliable operation.However,the growth of social economy leads to overload operation of buried cables,increase of working cycle,external force damage during construction and renovation,aging of insulation layer and moisture,etc.,which are prone to failure.Power cable fault detection usually goes through four key steps: fault type diagnosis,fault location,path detection and precise location.Each step requires dedicated equipment,so each detection needs to carry multiple devices,which is very inconvenient and wastes financial resources.Therefore,this thesis deeply studies the method of power cable detection,and designs a power cable comprehensive detection system based on the electromagnetic method and the acousto-magnetic synchronization method,which is applied to path detection and accurate fault determination.The main research contents are as follows:Firstly,combined with the development status of domestic and foreign power cable malfunctions detection,this thesis elaborates the reasons of power cable malfunctions and the unbroken course of cable malfunction detection.For precisely find the installation path of the underground cable,a special transmitter is used to inject a signal of a specific frequency into the cable to be tested,and a corresponding alternating magnetic field will be formed around the cable.Using the principle of electromagnetic induction,the magnetic signal sensor is used to identify the target magnetic field.to find out the cable location.After the cable fails,for precisely measure the precise position of the abort situation,a high-voltage pulse generator is used to exert a pulse signal to the malfunctioning cable to strike through the abort situation,and a release sound and a pulse magnetic signal will be produced at the abort situation,and the acousto-magnetic time difference will be measured.To judge the distance between the detection point and the fault point.For come true the intelligence and networking of the comprehensive detection system,NB-Io T is appended to acquire the place of the path detection and the data interaction of the Internet of Things platform,and the data is sent to the handheld device through Bluetooth for real-time display and the map is called to draw the cable path.Secondly,the signals collected on site will inevitably be affected by factors such as environmental noise and the noise of the detection system itself,which will bring difficulties to the recognition of the alternating magnetic field signal and the recognition of the discharge sound.In order to solve the problem that the target signal is difficult to identify due to the low signal-to-noise ratio,a weak magnetic field signal extraction method is studied,and the target signal is extracted by a narrow-band filter.Aiming at the problem that the end points of the sound signal of flashover discharge are not easy to detect,which leads to a large error in accurate positioning,based on the study of wavelet analysis,the wavelet threshold denoising is used to process the noise signal,and then the short-term energy method is used to obtain the discharge sound.starting point.In order to obtain the discharge sound that is easy to hear,the background noise of the sound signal is suppressed by the combination of wavelet threshold denoising and spectral subtraction.Simulation in MATLAB validates its effectiveness.Then,a comprehensive detection system for power cables is designed based on ARM processor.The hardware circuit design of the detection terminal is completed and the subsistent signal conpleteness problems are researched.On account of the One OS operating system,an arm environment is construct,and the system software design is completed,containing functions of signal collection,signal handling,and data communication.On account of the uni-app framework,the application software is designed,and the data communication is accomplished with the detection terminal by the Bluetooth interface to come true the real-time display of the test message and invoke the map to acchieve the drawing of the cable path.Finally,the power cable comprehensive detection system designed in this thesis is in line with practical applications,and can quickly and accurately realize the functions of the integration of cable path surveying and mapping and the precise location of cable faults.