变电站系统过电压防护技术文献翻译模板

资料内容仅供您学习参考，如有不当或者侵权，请联系改正或者删除。毕业论文(设计)文献翻译本翻译源自于:.com/p-.html毕业设计名称:变电站数据采集系统设计外文翻译名称:变电站系统过电压防护技术学生姓名:赵文浩院(系):电子信息学院专业班级:电气10803指导教师:唐桃波辅导教师:唐桃波时间:至

变电站系统过电压防护技术学生:赵文浩,电子信息学院指导教师:唐桃波,长江大学变电站的过电压保护是以电子信息系统为保护核心,为被保护设备构建一个均压等电位系统,并经过各级过电压浪涌保护器逐级把电流泄放入大地,使变电站设备全和可靠地运行。1变电站过电压防护近年来,变电站的通信、通信系统、继电保护系统、后台管理模块经常发生过电压损毁事件,究其原因主要是其相关系统和弱电产品过电压防护水平较弱,甚至根本没有过电压防范技术措施,其后果对电网的安全运行带来了较大负面影响。随着综合自动化系统和通信自动化系统等二次弱电系统在变电站的广泛应用,这类电子系统(设备)元器件的集成度愈来愈高,信息存储量愈来愈大,速度和精度不断提高,而工作电压只有几伏,信息电流仅为微安级,因而对外界干扰极其敏感,特别对雷电等电磁脉冲和过电压的耐受能力很低。当雷电等过电压和伴随的电磁场达到某一阀值时,轻则引起系统失灵,重则导致设备或其元器件永久性损坏。尽管雷电直击电子系统(设备)的可能性不大,可是雷击附近大地、建筑物、交流供电线路和空中雷云放电时直接形成的,或者由于静电感应及电磁感应形成的冲击过电压,都有可能经过与之相连的电力线路、信号线路或接地系统,经过各种接口,以传导、耦合、辐射等形式,侵入电子系统(设备)并酿成严重的干扰或事故。因此,加强和改进电子系统(设备)的防护,尽量减小其遭受雷电等冲击干扰损害造成的直接损失和间接损失,已成为当今亟待解决的问题。2过电压保护设计IEC(国际电工委员会)TC／81技术委员会将防雷分为外部防雷和内部防雷两个部分,外部防雷是指避雷针(或避雷带、避雷网)、引下线和接地系统,是被保护物体免受直接雷击;内部防雷则是防止雷电和其它内部过电压侵入设备造成的毁坏。一个完善的防雷及过电压保护系统必须综合运用泄流(分流)、均压(等电位)、屏蔽(隔离)、接地、限压(箝位)保护等各项技术,按照外部防雷和内部防雷的原则,根据防护对象的特点,灵活应用,采取具体措施,构成一个完整的防护体系。变电站内的过电压形式主要有:雷电过电压、工频过电压及谐振过电压、操作过电压等,这些过电压以传导或电磁感应的方式在线路及设备上形成危险的过电压,特别是雷电过电压,雷击变电站时,会在低压供电系统及弱电系统产生很强的感应过电压,同时使变电站的地电位升高(例如:变电站的接地电阻为1Q,雷电流为10kA,则地电位为10kV),因地电位升高造成对线路及设备的反击而损坏线路及设备的事件时有发生,因此,尽管变电站的外部防雷系统(避雷针．引下线及接地装置)符合国家及部颁标准的要求,且其综合自动化和通信自动化等二次弱电系统也采取了诸如屏蔽、接地、隔离、滤波等措施,但却不能完全避免强大的雷电过电压及电压反击对系统造成的干扰和破坏,因此,变电站二次弱电系统内部防雷及过电压也必须采取相应的防护措施,按照IEC内部防雷EMP的分区,对设备的电源线、信号线、数据线等加装内部防雷及过电压器件,防止雷电感应、雷电流沿线窜人、电压反击、浪涌过电压等瞬间暂态过电压造成系统故障及损坏电子设备。浪涌过电压保护器根据其接线方式分为串联和并联两种,使用串联浪涌过电压保护器时,有可能存在由于传输信号不匹配的原因导致对传输信号有干扰的情况,特别是数据通信接口在串人浪涌过电压防护器后,会产生数据无法正常通讯。因此,在数据通讯接I:I中串人浪涌过电压防护器后,必须对数据的传输情况进行认真检查,如发现数据无法正常传输,则有可能是由于不匹配的原因导致对传输信号的干扰,应更换相匹配的浪涌过电压防护器。如果在使用浪涌过电压防护器时采用并联方式,基本上不存在上述情况,但这种接线方式对浪涌过电压防护器的技术要求更高。3变电站系统过电压防护3．1站用电系统过电压防护安装在变电站内的通信调度自动化系统大多采用交流电源或直流电源为其设备供电,在其整流环节,一般有较大容量的滤波电容,对瞬态过电压冲击有一定的吸收作用,站用变压器低压侧到站用馈电屏之间采用的是屏蔽电缆且设备都有良好的接地,运用现代防雷技术来分析,必须增加回路的分流措施,因为其工作接地、保护接地都与其它电气设备采用同一接地装置,而且设备都处于LPZOB区,电磁脉冲强度相对较强,在站用变低压侧虽然有防止线路侵人波的避雷器,但残压高,因此在变电站遭受雷击时,经过线路耦合和地电位升高而造成的反击过电压依然存在,而且高压侧的残压高达几千伏,因此必须对这些调度自动化设备的供电回路进行过电压保护。根据雷电防护区域的划分原则,变电站内二次设备供电系统感应雷电过电压的防护能够按两级(B、C级)来进行分流保护。B级防雷一般采用具有较大通流容量的防雷装置,能够将较大的雷电流泄散入地,从而达到限流的目的,同时将过电压减小到一定的程度,c级防雷采用具有较低残压的防雷装置,能够将回路中剩余的雷电流泄散人地,达到限制过电压的目的,使过电压减小到设备能耐受的水平。电源系统的防护主要是抑制雷电及操作在电源回路上产生的浪涌和过电压。根据变电站的现状,对变电站的二次系统感应雷及操作过电压采用两级防护。由于变电站多建在较为空旷的区域,电磁强度相对较强,电力线路和通信电缆是很容易遭受到感应雷电的袭击,感应过电压沿着电力线路和通信线路进人设备,从而将设备损坏,因此,交流母线处加装第一级电源防护(B级)是为了保证整个控制室的安全,而且将80％的过电压泄散到大地,起到初级保护的作用,但在交流馈线上仍有部分过电压和B级电源防雷的残压加在线路上,因此必须在重要的交流馈线处(直流充电屏、UPS等)进行c级电源防护,从而将过电压抑制到后端用电设备能够耐受的水平。3．1．1第一级防护处理措施防护位置:据1EC1312(雷电电磁脉冲的防护》中的雷电保护区域的划分原则。避雷器的安装位置应在不同保护区的交界处,对于此网络即第一级防护应设在交流母线处。在两根母线上各加装一个同型号的B级三相电源浪涌过电压保护器。安装位置:交流母线(机柜内)。3．1．2第二级防护处理措施对于较为重要的交流馈线上的设备,此处为直流充电屏,加装c级三相电源避雷器。由于直流充电屏是两路交流供电,因此在直流充电屏处加装两个同型号的c级三相电源浪涌过电压保护器。安装位置宜选择在直流充电屏交流电源空气开关处。3．2综合自动化系统过电压防护防护位置:微机型综合自动化系统承受过电压的能力极低,几百伏的过电压就足以将设备损坏,因此必须对高压侧避雷器的残压(几千伏)进行进一步的抑制,以满足设备绝缘水平的需要,同时由于地电位升高而感应到电源回路零线的过电压也高达上千伏,因此必须在采用交流综合自动化系统的交流回路上加装c级单相浪涌过电压保护器。安装位置宜选择在综合自动化屏交流电源空气开关处。3．3不间断电源设备(UPS)过电压防护防护位置:由于内部计算机系统、集线器、监控设备、电能量计费系统等均经由UPS供电保护,为了保障以上微电子设备的安全,故在UPS电源装置前端加装c级浪涌过电压保护器。选用型号:选用(UPS为单相电源输入时)C级单相电源浪涌过电压保护器或(UPS为三相电源输入时)的c级三相电源浪涌过电压保护器。安装位置宜选择在UPS电源进线前端。3．4通信接口过电压防护通信接口过电压防护同电网供电系统相比,此回路对过电压的敏感程度要高得多,且这些设备在有过电压的情况下显得非常脆弱。设备的绝缘耐受水平也相当低。与这些设备相连的有信号线、数据线、测量和控制线路,而且这些线路基本上是处于LPZOB区域,也有穿过LVZOA区域的,线路上的感应过电压相对较强,根据IEC的测试,当电磁场强度增大到0．07GS时,微型计算机设备将产生误动,丢失数据。而且这些回路运行的安全与否直接关系到一次系统设备的安全,因此须对重要回路的接口进行过电压防护。3．4．1微机远动设备接口过电压防护防护位置:由于变电站微机远动装置采用分布分散式结构。由遥信模块、智能遥测模块、智能遥控模块、智能遥调模块组成。各单元模块都装设在不同的自动化屏内,模块之间经过RS232接口或现场总线进行通信。这些接口线路都处在室内,设备接口线路的距离较短,因此不会感应到较强的过电压,可是各自动化设备与其它二次设备(测量单元、计算机等)有电气连接,当其它二次设备感应到很强的感应过电压时,将会反击到这些自动化设备的通信接口上,从而使设备接口电路损坏,因此有必要在这些设备的接口上加装RS232的浪涌过电压保护器。安装位置宜选择在微机远动装置通信线路接口处。3．4．2电能量计费系统信号过电压保护防护位置一:变电站采用多功能电子电能表进行电能量采集,电子电能表承受过电压的水平极低。由于电能表与站内微机远动设备的通信采用RS232的接口,其通信线路较长,又处在LVZOB区域,在变电站附近或变电站遭受直接雷击时,将感应出较强的感应过电压,为了防止设备的损坏。在靠近电子电能表的RS232端口加装RS232的浪涌过电压保护器。安装位置宜选择在靠近电子电能表的RS232端口处。防护位置二:电子电能表采集的信息经过集中采集器的MODEM(调制解调器)由电话线将数据传送到远端,由于电话线路从室外引入,线路上感应到的感应雷电流相对较强,容易将调制解调器设备的接口损坏,因此必须在调制解调器的电话线路接口处加装一个接口浪涌过电压保护器。安装位置宜选择在内线电话出线端和外线电话的人线端。3．4．3远方通信接口过电压保护防护位置:由于变电站基本采用无人值守。对一次回路的各种保护、测量、控制、调节信号经过光纤、数据通信网络或载波向远方(省调、地调、集控站等)传送数据。如果采用载波,由于载波机与微机自动化装置的信号连接线路相对较长,在变电站附近或变电站遭受直接雷击时,处在LPZOB区的通信线路将感应出较强的感应过电压,因此必须在靠近微机自动化装置的信号接I:I端加装信号避雷器,同时处在LPZOB区并延伸到LPZOA区的通信线路(DDN、X．25)非常容易感应上雷电过电压,也必须加装浪涌过电压保护器。安装位置宜选择在远动装置通信线路接口处。变电站系统过电压防护问题是近年来提出的一个新课题,以上仅是结合本单位相关现场实际情况对防护技术措施的初步探讨,还需在不断吸取实际运行经验进行总结分析和不断完善,希望在今后新建变电站或者对老旧变电站进行综合自动化改造时,加强对过电压防护系统的同时规划和设计,确保设备和电网的安全稳定运行。

Substationsystemover-voltageprotectiontechnologySecondsubstationequipmentover-voltageprotectiononelectronicinformationsystemfortheprotectionofcoreequipmentfortheconstructionofaprotectedbothpressureandotherpotentialsystem,andthroughalllevelsofover-voltagesurgeprotectorsofthecurrentstepbystepintothelandofChina,Substationsecondarysafetyequipmentandreliableoperation.1secondover-voltagesubstationprotection

Inrecentyears,thesubstationcommunications,communicationssystems,protectionsystems,backgroundmanagementmodulefrequentover-voltagedamage,themainreasonforthisisweakanditsrelatedsystemsproductsover-voltageprotectionlevelisweak,ornoguardagainstover-voltageTechnicalmeasures,theconsequencesforthesafeoperationofpowergridsbringaboutagreaternegativeimpact.Withintegratedautomationsystemsandautomationsystemssuchascommunicationsystemsinthesubstationweaksecondarybythewideruseofsuchelectronicsystems(equipment)componentsoftheintegratedmoreandmore,thegrowingvolumeofinformationstorage,speedandaccuracyoftheIncreasedandoperatesonlyafewvolts,currentinformationonlymicroamplevel,thusextremelysensitivetooutsideinterference,especiallythelightningandelectromagneticpulse,suchasover-voltagetoleranceislow.Whenthunderandlightning,suchasover-voltageandaccompaniedbytheelectromagneticfieldsreachacertainthreshold,rangingfromsystemfailurecaused,resultedinheavyequipmentorpermanentdamagetoitscomponents.Despitethethunderandlightningviewpointofelectronicsystems(equipment)isunlikely,butlightningstrikeneartheland,buildings,communicationandairsupplylinedirectlyLeiyundischargeform,orbecauseofelectrostaticinductionandtheimpactofelectromagneticinductionformationofover-voltage,Theremightbeconnectedtothepowerlines,signallinesorgroundingsystem,throughvariousinterfacestotransfer,coupling,radiationandotherformsofinvasiveelectronicsystem(equipment)andleadtoseriousdisturbancesorincidents.Therefore,strengtheningandimprovingtheelectronicsystem(equipment)protection,tominimizetheimpactofinterferencebylightningandotherdamagecauseddirectlossesandindirectlosses,hasbecometheurgentneedtosolvetheproblem.2over-voltageprotectiondesign

IEC(InternationalElectrotechnicalCommission)TC/81minetechnicalcommitteewillbedividedintointernalandexternalminemineintwoparts,theexternalmineislightningrod(orwithlightning,lightningnetwork),YinXiaxianandgroundingsystem,Objectstobeprotectedfromdirectlightningstrikes,mineistopreventinternallightningandotherinternalover-voltagedamagecausedbyinvasiveequipment.Acomprehensivemineandover-voltageprotectionsystemsmustbeintegrateduseofdischarge(segregation),bothpressure(andotherpotential),shielding(isolation),grounded,limitpressure(clamp)protection,andothertechnology,inaccordancewiththeexternalmineAndtheprincipleofinternalmine,inaccordancewiththetargetsofprotectivefeatures,flexibleapplicationtotakeconcretemeasures,constituteacompleteprotectionsystem.Over-voltagesubstationintheformare:Lightningover-voltage,theresonantfrequencyover-voltageandover-voltage,over-voltageoperation,theseover-voltagetransmissionorelectromagneticinductiontothewaythelinesandequipmentonadangerousover-voltage,inparticular,Lightningover-voltage,lightningsubstation,inthelow-voltagepowersupplysystemandweaksystemtoproduceastrongover-voltagesensor,whilethesubstationtopotentialrise(forexample:thesubstationgroundingresistanceto1Q,lightningcurrent10kA,whilethepotentialfor10kV),duetotheincreasedpotentialofthecounterlinesandequipmentdamagedlinesandequipmentandtheeventshaveoccurred,therefore,despitethesubstationoutsidetheminesystem(lightningrod.YinXiaxianAndgroundingdevices)inlinewithnationalstandardsandtherequirementsofBuban,andtheintegratedautomationandcommunicationsautomationsystems,suchasweaksecondaryhavebeentaken,suchasshielding,grounding,isolation,filtering,andothermeasures,butitcannotcompletelyavoidover-voltagepowerfullightningAndvoltageofthesystemcounterthedisruptioncauseddamageand,therefore,thesecondweaksystemsubstationandamine-voltagemustalsotaketheappropriateprotectivemeasures,inaccordancewiththeIECwithinthemineareaEMP,thedevice'spowercord,signalLines,datalines,andtheinstallationoflightningprotectionandinternalover-voltagedevicestopreventlightningsensors,channelingpeoplealongthelightningcurrent,voltagecounterattack,suchastransientvoltagesurgetootransientover-voltagecausedbyafaultanddamagedelectronicequipment.Over-voltagesurgeprotectioninaccordancewithitsconnectionmodeisdividedintotwoseriesandparallel,theuseofover-voltagesurgeprotectiontandemwith,theremayexistbecauseofsignaltransmissiondoesnotmatchthecausesoftransmissionofthesignalinterference,inparticulardataCommunicationInterfaceintheserieswereover-voltagesurgeprotectioninplace,willhavethenormaldatacommunications.Therefore,thedatacommunicationsaccessI:Iintheserieswereover-voltagesurgeprotectioninplace,thetransmissionofdatamustbecarriedoutconscientiouslycheckifthedataarenotnormaltransmission,itmaybeduetothereasonsdonotmatchthetransmissionsignalInterference,shouldbereplacedtomatchtheover-voltagesurgeprotectionfor.Iftheuseofover-voltagesurgeprotectionforuseofparallel,thesituationisbasicallynon-existent,buttheconnectionmodeofover-voltagesurgeprotectionforhighertechnicalrequirements.3secondarysystemover-voltagesubstationprotection

3.1pointsover-voltageelectricitysystemprotection

SubstationinstalledinthecommunicationsdispatchautomationsystemsareusedACpoweroraDCpowersupplyequipmentfortherectificationofitslinksaregenerallylargercapacityfiltercapacitance,thetransientover-voltageshockabsorptionofacertainextent,thestationLow-voltagetransformersidegotofeedbetweenthescreenusingashieldedcableandequipmenthaveagoodgrounding,theuseofmoderntechnologytoanalyzemine,wemustincreasethecircuit'ssegregationmeasures,becauseitsgrounding,protectionandotherelectricalgroundingallGroundingdevicesusingthesameequipment,andequipmentareinaLPZOB,therelativestrengthofstrongelectromagneticpulse,thestationchangedtopreventlow-pressuresidealthoughtherearelinesintrusivewavearrester,buttheresidualpressurehigh,inthesubstationoflightning,throughthelineCouplingandthepotentialrisecausedbyover-voltagecounterattackstillexist,andhigh-pressuresideoftheresidualpressureashighasseveralthousandvolts,itisnecessarytotheseschedulingautomationequipmentforthepowersupplyover-voltagecircuitprotection.LightningProtectioninaccordancewiththeprincipleofregionaldivision,substationequipmentinthesecondarypowersupplysystemover-voltagesensorslightningprotectionmaybetwo(B,Clevel)fortheprotectionofsegregation.B-mineuseisgenerallygreaterflowcapacityofthemineinstallations,theLightningcouldbemorecasualLiuxiepeople,toachievetheobjectiveofcurrentlimit,over-voltageatthesametimewillreducetoacertainextent,c-mineuseWithlowerresidualpressureofthemineinstallations,youcanloopintheremainingscatteredlightningLiuxiepeople,tolimitthepurposeofover-voltage,over-voltageequipmentcanbereducedtotheleveloftolerance.Themainpowersupplysystemisinhibitedlightningprotectionandoperationofthepowerbacktotheroadandover-voltagesurge.Accordingtothesubstationstatusofthesubstationofthesecondmine-sensingsystemandtheoperationanduseoftwoover-voltageprotection.Asbuildmoresubstationsintheregionmoreopen,relativelystrongelectromagneticstrength,powerlinesandcommunicationcablesareveryvulnerabletolightningattackssensors,sensorsalongtheover-voltagepowerlinesandcommunicationlinesintoonedevice,whichwilldamageequipment,Therefore,theexchangeoffirst-classbustoinstallthepowerprotection(Blevel)istoensurethesafetyoftheentirecontrolroom,and80percentoftheover-voltageChina,scatteredtotheearth,playaprimaryroleintheprotection,butarestillintheexchangeoffeederSomeoftheB-levelpowersupplyvoltageandminetheresidualpressureincreaseson-lineandmustthereforebeimportantintheexchangeoffeederlines(DCchargingscreen,UPS,etc.)c-levelpowerprotection,whichwouldcurbover-voltageelectricalequipmenttoback-endTotheleveloftolerance.Protectivelocation:Itis1EC1312(LEMPprotection"intheregionoflightningprotectionprinciples.Arresterinstallationshouldbeindifferentlocationsatthejunctionofprotectedareas,thisnetwork,thefirst-classprotectionshouldbelocatedinthebusexchange.InTwoonthebuswiththeinstallationofaB-classmodelsofathree-phasepowersupplyvoltagesurgeprotector.

InstallLocation:ACbus(cabinet).

3.1.2second-classprotectionmeasurestodealwith

Forthemoreimportantfeederlinesontheexchangeofequipment,herefortheDCchargescreen,theinstallationofc-levelthree-phasepowerarrester.AsDCchargingscreenistwo-wayexchangeofelectricitysupply,sothescreenintheDCchargewiththeinstallationoftwomodelsofc-levelthree-phasepowersupplyover-voltagesurgeprotector.InstallationlocationshouldchoosetheDCchargescreenopenexchangeofairpower

CommissionerOffice.

3.2integratedautomationsystemover-voltageprotection

Protectiveposition:Computer-basedintegratedautomationsystem'sabilitytobearaverylowvoltage,severalhundredvoltsofover-voltageisenoughtodamagetheequipment,somustthehighsidearrestertheresidualpressure(thousandsofvolts)tofurthercurbtomeetequipmentInsulationlevelofneed,andbecauseofthepotentialrisetopowerandtheinductionloopisalsoover-voltagelineuponKV,tobeusedintheexchangeofintegratedautomationsystemtotheexchangeonthec-levelsingle-phaseinstallationofasurgeVoltageprotection.Locationshouldchoosetoinstallautomated-pingintheCompositeAirswitchtheACpower.3.3didnotaskoffpowersupplies(UPS)over-voltageprotection

Protectionhere:becauseoftheinternalcomputersystems,hubs,monitoringequipment,electricenergybillingsystemsandsoonthroughtheUPSpowersupplyprotection,inordertoprotectthesafetyofthesemicro-electronicsequipment,theUPSpowersupplydeviceinfrontoftheinstallationofac-SurgeVoltageprotection.Optionalmodels:The(UPSforsingle-phasepowerinput)C-classsingle-phasepowersurgeorover-voltageprotection(UPSforthethree-phasepowerinput)ofc-levelthree-phasepowersupplyover-voltagesurgeprotector.InstallationshouldchoosethelocationofUPSintothefrontline.

3.4communicationinterfaceover-voltageprotection

CommunicationInterfaceover-voltageprotectioncomparedwiththegridsupplysystem,thisover-voltagecircuitonthedegreeofsensitivityismuchhigher,andtheseareover-voltageequipmentinthecircumstancesitisveryfragile.Equipmentinsulationtolerancelevelisverylow.Withtheequipmentconnectedtoasignalline,datalines,measurementandcontrollines,andthesearebasicallyinlineLPZOBregion,butalsothroughtheLVZOAregion,onthelinesofsensorsover-voltagerelativelystrong,accordingtotheIECtest,whentheelectromagneticfieldStrengthincreasedto0.07GS,willhaveamicro-computerequipmentmalfunction,lossofdata.Andthesafetyofthesecircuitsisdirectlyrelatedtoasystemofsafetyequipment,soimportanttobeontheinterfacecircuitover-voltageprotection.

3.4.1remotecomputerinterfacedevicesover-voltageprotection

Protectiveposition:Assubstationcomputerremoteinstallationsscattereddistributionstructure.Fromremotemodules,intelligenttelemetrymodule,intelligentremotecontrolmodule,intelligentremote-module.Themodulesareinstalledindifferentautomated-ping,throughtheRS232interfacebetweenthemodulesorfieldbuscommunication.Theseinterfacesareintheindoorcircuit,equipmentinterfacecircuitsshorterthedistance,sotherewillbenomoresensorstotheover-voltage,buttheautomationequipmentandothersecondaryequipment(measurementunit,computer,etc.)haveelectricalconnections,whenOthersecondaryequipmentsensorstoastrongover-voltagesensors,willbecountertotheseautomationequipment,communicationsinterface,sothatdamagetoequipmentinterfacecircuits,itisnecessaryinthesedevicesRS232interfacesontheinstallationofasurgeVoltageprotection.Installationlocationshouldchoosetheremotecomputerinterfacedevices,communicationslines.

3.4.2electricenergybillingsystemsignalsover-voltageprotection

Aprotectiveposition:amulti-functionalelectronicpowersubstationtable,energyacquisition,theelectronicpowermetertobearaverylowvoltagelevels.AsMeterandremotecomputerstationsinthecommunicationsequipmentusedRS232interfaces,thecommunicationlineislonger,andinLVZOBregion,nearthesubstationorbydirectlightningstrikeatthesubstation,proximitytothehighvoltagesensors,Inordertopreventdamagetoequipment.E-MeterinandaroundtheRS232portRS232installationoftheover-voltagesurgeprotector.Locationshouldchoosetoinstallelectronicpowermeterinandaroundtheport,RS232.