Research On On-line Monitoring For The Condition Of Contact Wires' Connector Based On ZigBee

The overhead contact line plays an important role in the electrified railway,and its normal operation is directly related to the stability and safety of railway operation.With the rapid development of high-speed railway in our country,there are more and more troubles and challenges.There are a lot of detection technologies for the overhead contact line,and the detection of the contact line is usually the way of manual inspection.In order to make the detection more automated and overcome the shortcomings of manual inspection,in this thesis,it designs a kind of on-line monitoring system of the contact line status based on ZigBee wireless communication technology.Firstly,the principle of contact resistance generating and the major influence factor of contact resistance are analysed through electrical contact theory,and the corresponding contact temperature rise can be obtained by calculating the voltage drop of contact point under different contact force.when current is constant,the contact temperature rises with the increase of contact force,so the monitoring for the contact parts can identify whether the connector clamp is loose or not.On the basis of theoretical research,the monitoring system is designed in detail from the aspects of hardware and software.In the hardware part,the CC2530 peripheral circuit is used as the core of the design,and the technology of balun and USB-RS232 conversion is adopted.The circuit is stable and reliable.In the software part,each node of ZigBee programing is written in IAR development environment based on the Z-Stack protocol stack,and its unique compiling method improves the efficiency of software design.The design of the host computer interface is carried out in the VB.NET integrated development environment,with the help of the real object programming method,it has a good human-computer interaction monitoring interface.In order to solve the security problem of data transmission in the design of ZigBee,based on the 128 bit AES encryption algorithm,it adopts two security patterns including data encryption and data authentication.Data encryption can effectively prevent wireless data being monitored or stolen,and data authentication is to protect the integrity of the data itself.Finally,the on-line monitoring system designed and researched in this thesis has been tested in the laboratory,and it bisically achieved the expected purpose.Meanwhile,the experimental process of the ZigBee network topology and anti-jamming capabilities were tested to verify the self formation and self-healing characteristics of the ZigBee network.At present,the wireless temperature measuring device has been tested in a railway bureau power supply section,and the effect is stable,basically meeting the needs of the monitoring site.