地铁通信电源电磁干扰分析及其抑制

1、安全防护现代城市轨道交通5/2009MODERN U RBAN TRANSIT摘要：分析了地铁通信电源电磁干扰产生的原因，在此基础上探讨了抑制电源电磁干扰的措施，包括抑制零线及开关电源电磁干扰、雷击防护、选择正确的接地方式、不间断供电电源的选配等问题。关键词：电磁干扰；共模；差模；防雷地铁通信电源系统承担全线通信设备供电，由电源系统引发的电磁干扰（）可以从尖峰干扰到完全失电之间进行变化，干扰形式包括电压变化、频率变化、波形失真、静电放电等，轻者会造成通信设备数据误码率增大或数据丢失，重者会造成通信设备的“死机”或莫名其妙的关机，严重时，甚至会损坏通信硬件设备，从而造成通信系统的中断。电源电磁干

2、扰产生的原因通过电源进行传输并能够影响电子设备工作或造成其破坏的干扰，主要是电快速瞬变脉冲群和浪涌冲击波，而静电放电等只要电源设备本身不产生停振、输出电压跌落等现象，就不会对用电设备造成影响。电源电磁干扰产生的可能原因如下：（）由电感性或电容性负载的开关、功率因数补偿电容的切换、空载电动机的断开引起的电源瞬变；（）来自不带隔离变压器的、逆变电源或变频器等所产生的调制干扰；（）架空电力线或外接电池的空间电缆感应的电磁辐射干扰；（）由电源零线对地线的电位过高引起的干扰；（）由高频开关电源引起的干扰，功率开关器件的高额开关动作是导致开关电源产生电磁干扰（）的主要原因；（）由雷击所引起的电源跌落或高能

3、瞬态浪涌，雷电能量集中分布在工频附近，电源线引入感应雷击，通过阻性耦合方式经中线及地线破坏设备。抑制电源电磁干扰的措施在电源中要消除外来的瞬态浪涌、频率波动和各种电磁干扰所带来的不利影响，必须采用一定的抑制措施。抑制零线电磁干扰电源系统的零线对地线的电位过高时，在计算机通信接口插入连线时，轻者会造成计算机“死机”，重者会造成被烧毁。在地铁实际环境中，理想的地线是不存在的，当电流流过时必然会产生电压降。根据地线中干扰形成机理注意以下两点：第一，尽量降低系统接地阻抗和电源馈线阻抗；第二，正确选择接地方式和阻隔地环路。抑制开关电源干扰使电源干扰不对电子设备造成危害的根本办法是削弱噪声发生源，或者切断

4、电源噪声和电子设备之间的耦合途径。高频开关型稳压电源产生的电磁干扰辐射频率主要是电源工作频率的基波和二、三次谐波。开关管快速通断产生的浪涌电流和尖峰电压，是开关电源产生电磁干扰及开关损耗的主要原因。软开关技术是减小开关器件损耗和改善开关器件电磁兼容特性（）的重要方法。使用软开关技术，使开关管在零电压、零电流时，吸收开关管或高频变压器初级线圈两端的尖峰电压，能有效地改善电磁兼容特性。对开关电源二根进线而言，电源线干扰可以使用电源线滤波器滤张亦然汪曙明张亦然：南京地下铁道有限责任公司运营分公司，工程师，南京地铁通信电源电磁干扰分析及其抑制MODERN URBAN TRANSIT5/2009现代城市

5、轨道交通安全防护除，一个合理有效的滤波器应该对电源线上差模干扰和共模干扰都有较强的抑制作用。普通电源滤波器是由一些无损耗电抗元件构成的，能阻止频带以外的其他信号通过，而把一部分信号反射回信号源，这样反而导致干扰电平的增加而不是减小，有些电源产品使用群脉冲干扰对抗器，采用吸收与反射相结合的原理，克服了滤波器的上述缺点。抑制辐射噪声的有效方法就是屏蔽，为了防止变压器的磁场泄露，使变压器初次级耦合良好，可以利用闭合磁环形成磁屏蔽，开关电源的连接线、电源线都应该使用具有屏蔽层的导线，尽量防止外部干扰耦合到电路中，或者使用磁珠、磁环等元件，滤除电源及信号线的高频干扰。整个开关电源的外壳尤其接缝处也需要有

6、良好的屏蔽特性。选择正确的接地方式单点接地主要适用于频率低于的低频电路，为防止工频电流及其他杂散电流在信号地线上各点之间产生地电位差，信号地线与电源及安全地线隔离，在电源线接大地处单点连接。地铁车站沿线的主变压器处作可靠的单点接地，确保接地阻抗达到电气规范要求。同时将接地点引出到屏蔽笼子的外面，保证地电位为零电位，消除因电荷泄漏不完全而出现地电位漂浮的现象。选配高品质的供电系统。不同类型的提供不同级别的抗干扰保护。目前，可供选择的可大体分为两大类，非在线式和在线式。（）非在线式包括后备式、在线互动式和变换器型。对于后备式和在线互动式来说，当电网输入正常时，利用位于交流旁路通道上的稳压电路进行调

7、压控制，向用户提供稳压精度为的电源。对于变换型来说，它利用变换器对位于主供电通道上的“补偿变压器”执行数量级（标称输出电压）的“补偿”电压调控，提供稳压精度为的电源。在此条件下，电源输入端与输出端是没有电隔离的。仅当外电供电不正常时，上述种才向用户提供高质量的逆变器电源。显然，这种的主要设计功能是针对解决输入电压的波动问题，并不能解决电源的频率和谐波失真和其他干扰问题。（）在线式首先将输入电源变成稳压的直流电源，然后经逆变器变成稳定的纯净的高质量电源。值得注意的是，为适应不同的用户需求，在线式有不同的设计方案，向用户提供的抗干扰保护的级别也有所不同。按可提供的抗干扰保护的完善程度由高向低排序为

8、：双原边绕组输出变压器的在线式；带输出隔离变压器的在线式；不带输出隔离变压器的在线式等。带双原边绕组隔离变压器的，中线对地线电位极低，并可切断任何从电网串入的干扰。因此，选配高品质的供电系统是电源系统的最佳设计。电源雷击防护雷电是浪涌电压的一种，雷电对线路的感应和地电位反击是造成设备损坏的重要的原因，电源雷击的防护措施主要有：（）等电位连接，等电位连接的目的，在于减小防雷空间内各金属部件和各系统之间的电位差，即将机房内的主机金属外壳、及电池箱金属外壳、金属地板框架、金属门框架、设施管路、电缆桥架、铝合金窗的等电位连接，并以最短的线路连到最近的等电位连接带或其他已做了等电位连接的金属物上，且各导

9、电物之间尽量附加多次相互连接；（）室外电源线金属屏蔽及重复接地，对室外电源线，避免架空导线直接进入机房设备，尽可能埋地缆进入，并用金属导管屏蔽，屏蔽金属管在进入建筑物或机房前重复接地，最大限度衰减从各种导线上引入雷电高电压；（）加装防雷器，对线路中的瞬态过电流、过电压进行有效的抑制，电源防雷器分为、三级，地铁通信系统中采用级。结束语地铁通信各系统的安全正常运行，与电源系统的电磁兼容性能息息相关，随着地铁线路的不断增加，电源系统的电磁兼容性问题的重要性越来越受到重视，这就需要不断提高地铁电源系统的电磁兼容性。参考文献林国荣电磁干扰及控制北京：电子工业出版社，王庆斌，刘萍电磁干扰与电磁兼容技术北京

10、：机械工业出版社，威廉斯电磁兼容设计与测试李迪译北京：电子工业出版社，收稿日期地铁通信电源电磁干扰分析及其抑制张亦然等ABSTRACTSTechnical Points and Revision in Implementation of GB Passen-ger Transport Service Marks of Urban Rail TransitLi Weijun, Wang Juan1The GB/T18574-2008 of Passenger Transport Service Marks ofUrban Rail Transit, revised by 16 units mod

11、erated by Beijing Instituteof Metro Design, formally implemented on June 1, 2009. In order tohave a correct understanding of the GB/T18574-2008, the technicalpoints supporting the GB clauses as well as the main revised contentsare introduced.Comparison and Analysis of Transmission Techniques of Com-

12、munication System in Urban Rail TransitZhang Yuping9The several frequently-used transmission techniques of communi-cation system in urban rail transit are introduced. These techniquesas well as the operations carried by communication system of urbanrail are compared and analyzed. Thus a scheme with

13、comprehensiveapplication of Multi-Service Transport Platform (MSTP and Resil-ient Packet Ring (RPR Technology is presented, which can be a moreprospective transmission scheme for future communication systemin urban rail transit.Analysis on Setting Scheme of Control Center with Network Op-eration in

14、Urban Rail TransitDing Jinchun12With the development of urban rail transit, the rail transit of somecities has been networked. For the network-based urban rail transit,how to set the control center becomes a new project. From the devel-opment review of setting forms for the control center of various

15、 stagesin different urban rail transit lines, as well as the analysis and sum-mary of construction, change and setting mode of the control centerin Beijing rail transit lines, the development trend of setting for con-trol center in urban rail transit with network operation is introduced,and the sett

16、ing scheme is suggested.Study on New Method of Anti Pollution Flashover Using Porce-lain Insulator of Contact Lines in Electric RailwayZeng Qinyuan19Based on the analysis of the cause for pollution flashover, themeasures for preventing pollution flashover are introduced. In orderto promote the opera

17、tion reliability of China electric railway, the antipollution flashover performance of porcelain insulator should beimproved by using carefully chosen porcelain materials, new designof product structure and modern manufacturing technology. On thepremise of fulfillment of the mechanical strength stip

18、ulated by na-tional standard, using the porcelain insulator produced by isostaticpressing technology can decrease the shaft diameter and increaseumbrella diameter, thereby increasing the creepage distance and en-hancing pollution flashover voltage of porcelain insulator. The de-signed open umbrella-

19、shape structure sufficiently utilizes the aero-dynamic principle, and improves self-cleaning and pollution-resis-tance capability of porcelain insulator. The manpower pollution-re-sistance voltage value of porcelain insulator produced by this newmethod of anti pollution flashover is 40 kV, which is

20、higher than thevalue of 36 kV stipulated by national standard.Determination for Installed Capacity of Rectifier Transformerof Power Supply System in Urban Rail TransitChen Jianguo, Fang Ming22Based on the principle of capacity matching between transformerand rectifier, the new method for determining

21、 the installed capacityof rectifier transformer is proposed. Then, taking the power supplysystem substation of Rail Transit Line 1 in a city as an example, theinstalled capacity of rectifier transformer is calculated and determined.Compared with the actual installed capacity of rectifier transformer

22、,the installed capacity determined by this method can meet the re-quirement of actual train operation.Repair Technology and Equipment for Wheel Flange and TreadZhang Yanfang26The wear is inevitably for wheel flange and tread during operation.The technical requirement for wheelset repair is proposed.

23、 The tech-nology of measurement, repair welding and turning repair for wearof wheelset tread and flange is discussed. The repair technology, thedevelopment of equipment and the application of new technologyand new equipment are introduced.Experimental Study on Effects of Shield Construction Param-et

24、ers of Metro Tunnel on Ground SettlementJin Ming, Si Xiangyu, Yang Ping32Taking the tunnel of Yi-Da section in Nanjing Metro Line 2 asbackground, the effects of shield construction parameters (includingpropulsion, earth pressure on working face, cutterhead torque and soon in the shield construction

25、on ground settlement are studied. Therules of ground settlement are summarized by analyzing the fieldmonitoring results, which have guiding significance for subsequentproject construction.Line Arrangement in Urban Rail Transit DepotChen Yizhi, Wang Lvzhi45The general arrangement of urban rail transi

26、t depot and the vari-ous functional line arrangements in the depot are analyzed by thedesign practice as well as using the design experiences of severalurban metro lines for reference. Some concrete implementation sug-gestions are proposed, including double angle design adopting No. 7turnout frog an

27、gle, and bay washing track simultaneously linkingtransfer track and lead track.Analysis and Suppression of Electromagnetic Interference toMetro Communication Power SupplyZhang Yiran, Wang Shuming51The reasons for generation of electromagnetic interference (EMIto metro communication power supply are analyzed. On the basis ofthis analysis, the measures for suppressing EMI to power supply arediscussed, including the suppression of EMI to zero line and switch-ing power supply, the lightening prevention, the selection for propergro