电力系统自动监控技术交流数据采集与处理课件

变电站综合自动化信息的测量与采集1.主要内容变电站综合自动化信息交流采样技术状态量信息的采集

2.变电站综合自动化信息

两大类信息：第一类是与电网调度控制有关的信息，它们在变电站测量采集后，由综合自动化系统向上级监控或调度中心传送；第二类信息是为实现站内监控所使用的信息。信息包括模拟量、开关量、脉冲量等。

3.变电站综合自动化信息

1.模拟量信息（1）输配电线路的U、I、P、Q、cosφ、kWh、kVARh等；（2）不同电压等级母线的线电压、相电压、序分量电压等；（3）变压器各侧U、I、P、Q、cosφ

、kWh、kVARh等；（4）直流母线电压；（5）所用变低压侧电压；

4.变电站综合自动化信息

（6）母联的U、I、P、Q、cosφ、kWh、kVARh等；（7）并联补偿装置的电流；（8）变压器上层油温。

5.变电站综合自动化信息

2.开关量信息（1）变电站事故总信号；（2）断路器位置信号；（3）变压器中性点接地隔离开关的位置信号；（4）重要隔离开关的位置信号；（5）继电保护动作信号；（6）直流系统接地信号等。

6.变电站综合自动化信息

3.设备异常和故障预告信号（1）控制回路断线总信号；（2）断路器操作机构故障总信号；（3）变压器油温过高信号；（4）轻瓦斯动作信号；（5）继电保护系统故障总信号；（6）消防报警信号；（7）通信线路故障信号。

7.模拟交流量的变送器测量与采集

不同电压等级的电压和电流经过电压互感器和电流互感器的变换后，变为额定值为100V的电压和5A（或1A）的电流，变电站自动化系统对它们进行测量和采集，得到系统的电压、电流、有功功率、无功功率、功率因数、有功电度、无功电度等运行参数。

采集和测量的方法有两种，即应用变送器的直流采样法和直接对交流信号进行测量、计算的交流采样法。此处仅介绍交流采样法。8.微机变送器与交流采样一.微机变送器硬件原理微机变送器的功能是测取电压、电流、功率、电能等电气量，并以数字形式输出给远动装置或就地显示系统。微机变送器是以微处理器为核心的微机系统.9.TypicalhardwarestructureThefollowingFigureshowsthegeneralhardwareoutlineofanumericprotectionrelay.Itconsistsof:

GalvanicIsolationTransformerAnti-AliasFilterS/HAmplifierMultiplexerADCMicro-ProcessorTimer10.VaS/HVbS/HVcS/HIaS/HIbS/HIcS/HMUXADCμPTimerROMRAME2PROMSIOModemK&DPIODIDOTripCBOpen11.

ROM:

ReadOnlyMemoryRAM:RandomAccessMemoryE2PROM:ElectricallyErasableProgrammableReadOnlyMemorySIO:SerialInputandOutputportK&D:KeyboardandDisplayPIO:ParallelinputandoutputPortDI:DigitalInputInterfaceDO:DigitalOutputInterfacePowerSupply

12.GalvanicIsolationTransformer220kVNumericrelayTVTATV:Highvoltage100V(LtoL)TA:Largecurrent5Aor1AIncaseoffault,voltageusuallygoesdownandcurrentgoesup.Voltagewillbe0to100Vandcurrentmayashighas25timesoftheratedcurrent,thatis125Aor25A.13.ThevoltageandcurrentarestilltoobigfortheAAF,S/H,MUX,ADCandotherelectroniccircuit.Voltagesignalismoreeasytocopewiththancurrentsignal.Socurrentsignalshouldbetransformedintovoltagesignal.Internalgalvanicisolatingtransformersareusedtoimplementthetransformation..14.Voltagetovoltagetransformer57V5V57V5VDirectvoltagetransformingIndirectvoltagetransforming2.5mA2.5mA15.Currenttovoltagetransformer125A5V5VI-VTransformingbyInductanceTransformer2.5mA125AI-Vtransformingbycurrenttransformer16.AnotherfunctionofthetransformersInadditiontostepdownthevoltageandcurrent,thereisstillanotherfunctionofthetransformers.ThatisprovidinggalvanicisolationbetweenTA,TV’ssecondarysidesandelectronicprocessingcircuittodepressthecommonmodeinterference.17.Commonmodeinterference57V5VTVSecondary~Noise~Noisehasveryhighfrequency,andcanmakethe0Vlinehavepotentialdifference18.Commonmodeinterference57V5VTVSecondary~Noise~Noisehasveryhighfrequency,andcanmakethe0Vlinehavepotentialdifference19.Anti-AliasFilterAnti-Aliasfilter(AAF)isalsoknownasAnalogueLow-passFilter(ALF).Itsfunctionistoeliminatethehighfrequencycomponentofinputsignalandtosatisfythesamplingtheorem.PassiveRClowpassfiltersareoftenused,asshowninfollowingfigure.20.21.DigitalInputInterfaceDigitalInputs:

Statusofcircuitbreaker,Statusofsomeisolators,Statusofotherprotectiverelay,Statusofsomefunctionalswitchesandlinkers.Thestatusare

determinedby‘ON’or‘OFF’ofcorrespondingswitches.22.PA05VDIinterfaceforinternalswitchesK0V23.PA05VDC220VKPA0DC220VKMKMDC24VK5VDC220VPA0KDC24V5V24.DigitalOutputInterfaceDigitalOutput:

IssuetripcommandIssueclosecommandIssuealarmsignalStartasignaltransmitterBlocksignalOtherkindofdigitalout25.

PB0PB1

J5V24V26.DCsupplyDC/DCConverterDC220VorDC110V5V+12V-12V+24VGalvanicisolatedswitchedDC/DCconverter27.采样保持器

Function:holdtheinputsignalataconstantanaloguelevelforthedurationofconversiontoeliminateconversionerror

28.原理电路

29.工作过程30.波形31.基本要求:32.Ch的选择IfChisbecomingsmaller,thenthesamplingtimeandtheholdtimewillbecomeshorter.IfChisbecominglarger,thenthesamplingtimeandtheholdtimewillbecomelonger.Accordingtothebasicrequirement,samplingtimeshouldnotbetoolongandholdtimeshouldbenottooshort,soChshouldnotbetoolarge,nortoosmall.Usually0.01uFisselectedinrelay.Theleakagecurrentshouldbesmall

33.多路切换开关Function:Ingeneralcase,relaysneedmulti-channelinputs(3phasevoltage,3phasecurrent,zerosequencecurrentetc.)34.Forthesecondcase,AmultiplexerisneededtoswitcheachoftheinputchanneltotheinputofADCsequentially.TwowaysAnindividualADCforeachanalogueinputOnlyoneADCforallanalogueinput35.原理电路Atypical16to1multiplexerisshownas:36.37.基本要求

Switchingtime---shortRon----------------smallRoff----------------large38.微机变送器与交流采样

四．A/D转换器

实现A/D转换的方法很多，有逐位比较式、记数式、并行比较式等等。逐位比较式A/D转换就是将待转换的直流电压与一组呈二进制关系的标准电压逐位地进行比较，得到一组标准电压的记数值，这组记数值就是模拟电压的二进制数字量形式，从而实现了A/D转换。

完成A/D转换所需的一组标准电压，由D/A转换网络产生。常用的D/A转换网络有T型网络（又称R-2R数/模转换网络）和权电阻网络。

39.DigitaltoanalogueconvertersToaidtheunderstandingofA/D，DACwillbedescribedfirstly.Abasic4bitDACisshownasfollow:

（见下图）40.Themagnitudeoftheanalogueoutputisdeterminedbythedigitalinput.41.Analoguetodigitalconverters:rampconverters42.43.WhentheDACvoltageexceedstheanalogueinput,thecomparatoroutputwillgolowandblockcounter.ThemaindefectsoftherampADCistheconversiontimeislongandnotaconstant.44.

逐次逼近式A/D转换器

45.转换过程Analoguevoltagepresentontheanalogueinput(withmagnitudeequalsto11.3)StartsignalactivatePriortotheconversion,alldatalinesettozero,DACoutputiszero.Fistclock:SetD3=1,thenDACoutputgoestohalfofitsmaximumoutput(thatis16/2=8)

46.Nextclock:successivelogicsensestheDACoutputisstilllowerthaninputsignal,thussetD2=1,thenDACoutputgoesto12(8+4)Thirdclock:thedigitalequivalentisgreaterthantheanalogueinputduringthelastclockperiod,soD2isclearedtozeroagainandD1issettohigh.NowtheDACoutputequalsto10(8+2)47.Fourthclock:sinceDACoutputduringthethirdperiodislowerthantheinput,thenD1remainshighandD0issettohigh,atlast,theresultis1011B=11DEndofconversion:enablethedatabuffe