基于时域反射技术的风机叶片防雷接地故障快速检测系统OA

In order to solve the problem of lightning protection system failure caused by faults such as breakage and poor contact of wind turbine blade lightning protection downleads,and to overcome the shortcomings of traditional resistance measurement methods that require shutdown and disassembly and low efficiency,a portable rapid detection system based on Time Domain Reflectometry(TDR)technology was designed and developed.The system injects high-frequency pulse signals into the lightning conductor,determines and locates faults by analyzing the characteristics of reflected waves;the hardware integrates a pulse generation module(pulse width 100～200 ns,amplitude adjustable),a high-speed acquisition module(50 MHz ADC),a processing unit(FPGA+microprocessor)and a human-machine interface.The fault distance is calculated by using the pulse propagation speed and reflection time difference in the conductor,and the fault type(open circuit,short circuit)is determined through the reflection coefficient.Through actual blade testing in the laboratory and wind farm,the system's positioning error for open and short circuit faults on 20～200 m conductors is less than 5%(the laboratory standard deviation is less than 2%),and the relative error for actual blade detection on site is less than 3%.In addition,the detection accuracy in a strong interference environment exceeds 90%,and the positioning error is controlled within±2%.The average time for a single detection process(including wiring,measurement,and analysis)is less than 5 minutes.The results show that the time domain reflection technology detection system realizes non-contact,rapid and accurate location and type judgment of lightning protection downlead faults of wind turbine blades,and can improve the efficiency and safety of wind power operation and maintenance.