高速铁路信号设备通信接口雷击过电压损伤试验研究

Experimental Study on Lightning Transient Overvoltage Damage of Interface Devices of High-speed Railway Signal Equipment

本文提出一种关于高速铁路信号设备通信接口雷击过电压损伤检测及判定方法,是对当前高速铁路信号设备通信接口雷击试验及检测方法的优化和完善。首先,对雷电波频谱进行了分析,确定了信号设备通信接口雷击试验波形和检测电路。然后,选取ZPW-2000A轨道电路系统的CAN通信接口器件PCA82C250和编码读取电路的光耦TLP621-4作为试验对象,按电压幅值由低到高分别对其进行雷电冲击试验。试验结果表明:PCA82C250横向雷电冲击损坏电压约为88V,纵向雷电冲击损坏电压约为48V;光耦采集电路中,直接对光耦进行雷电冲击时,雷电冲击损坏电压约为140V;在雷电冲击点与光耦间串入4.7kΩ电阻后,雷电冲击损坏电压约为800V,故增加器件的输入阻抗,可以提高耐雷电冲击水平。最后,讨论分析了信号设备通信接口器件的雷击过电压损伤特性,分析结果表明:信号设备通信接口器件的雷击过电压损伤特性分为3个阶段,即正常阶段、临界损伤阶段和损坏阶段;信号设备通信接口器件存在冲击损坏积累效应,当器件处于临界损伤阶段时,仍可进行数据传输,但输出信号与正常阶段不一致。信号设备通信接口器件雷击过电压损伤检测,应按电压幅值由低到高进行雷电冲击试验,以冲击时是否有击穿现象和通信线上信号电平是否发生异常作为损伤判定的基本依据,并结合相应测试标准等,做出科学准确的判断。

This article proposes a method for detecting and determining the lightning overvoltage damage in communication interfaces of highspeed railway signal equipment,which is an optimization and improvement of the current lightning test and detection methods for communication interfaces of high-speed railway signal equipment.Firstly,an analysis of the lightning wave spectrum is conducted to determine the lightning test waveform and detection circuit of the communication interface.Subsequently,the CAN communication interface device PCA82C250 of the ZPW-2000A track circuit system and the optocoupler TLP621-4 of the encoding reading circuit were selected as the test objects.The lightning impulse tests were conducted on the test objects with gradually increasing voltage amplitudes.The test results showed that the transverse lightning impulse damage voltage of PCA82C250 is about 88 V,and the longitudinal lightning impulse damage voltage is about 48 V.In the optocoupler acquisition circuit,when the lightning impulse is directly applied to the optocoupler,the voltage damaged by lightning impulse is about 140 V.By connecting a 4.7 kΩresistor in series between the lightning impulse point and the optocoupler,the lightning impulse damage voltage is about 800 V.Therefore,increasing the input impedance of the device can improve the lightning impulse resistance level.Finally,the lightning overvoltage damage characteristics of signal equipment communication interface devices were discussed and analyzed.The analysis results showed that these characteristics can be divided into three stages,which are the normal stage,the critical damage stage,and the damage stage.There exists an accumulation effect of impact damage on these components.When the components are in the critical damage stage,data transmission can still be carried out,but the output signal is inconsistent with the normal stage.The detection of lightning overvoltage damage to communication interface devices of signal equipment should be carried out through lightning impulse testing with gradually increasing voltage amplitudes.The basic criteria for damage determination is the presence of the breakdown phenomenon during the impulse and the abnormal signal level on the communication line.Furthermore,scientific and accurate judgments should be made in conjunction with corresponding testing standards.