High Frequency Characteristics And Development Of Monitoring System For 27.5kV Metal Oxide Surge Arrester

With the rapid development of China ’s high-speed railway system,the train speed is increasing,and the safe and stable operation of railway equipment is required higher.As an important protective equipment widely used in railway system,27.5k V metal oxide surge arrester(MOV)plays an important role in the safe and stable operation of the train.But in recent years,the operation failure of the arrester in the railway has occurred from time to time.In addition to the common failures such as aging,damp,pollution and over-voltage,the failure of the arrester under the high harmonic voltage becomes more and more serious when the resonance of the traction network due to the mixed running of multiple trains in the railway line.At present,there is no comprehensive analysis on the operation state,failure mechanism and withstand characteristics of the arrester under the high harmonic voltage,nor the arrester monitoring system specially designed for the operation characteristics of the railway system,which can effectively deal with the operation failure of the arrester in the railway.Therefore,this thesis conducts in-depth research on these problems.In this thesis,the test system and scheme for testing the operation state of 27.5k V MOV under the action of high harmonic voltage are established.The test system consists of high frequency and high voltage source,measuring equipment and data acquisition and analysis equipment.The test scheme includes applying harmonic voltage to aging and non-aging arresters respectively,finally obtaining their operation rules and establishing their wide frequency domain model,which is applicable to the action of high harmonic voltage.Through the equivalent model to explore the high frequency fault mechanism and withstand characteristics of arrester under the action of high harmonic voltage,to provide theoretical and data support for the design of the railway arrester monitoring system.In the design of the lower computer of the arrester monitoring system,in order to realize the accurate and real-time monitoring of the state of the arrester,the identification of the fault type and the upload of the monitoring data,high-precision sensors are selected to collect the leakage current and the voltage signals of the arrester,and the algorithm program based on AD chip and DSP chip is compiled to control the lower computer.The lower computer adds the SMS early warning module,which makes the monitoring system function more complete,and the monitoring personnel can find and deal with the fault in time.In the design of the upper computer of the arrester monitoring system,the efficient and convenient Visio Studio software is used for programming to realize data processing,visualization of the monitoring interface and human-computer interaction.The monitoring interface includes the real-time display of the overall state and rend of the arrester,the display and warning of its characteristic parameters for different fault types,and the record display of fault information.Finally,through the laboratory testing,it is verified that the monitoring device can be put into operation initially,which provides a strong guarantee for the safe operation of the arrester.