Symmetric Component Filter 对称分量滤过器

项目二继电保护基本元件Project2BasiccomponentsofRelayProtection

课程负责人：关娇娇张勇CourseLeader：GuanJiaojiaoZhangYong

课程负责人：关娇娇张勇CourseLeader：GuanJiaojiaoZhangYong任务二对称分量滤过器Task2SymmetricComponentFilter教学要求:掌握零序分量滤过器、负序分量滤过器工作原理以及分析方法。Teachingrequirements:mastertheworkingprincipleandanalysismethodofzero-sequencecomponentfilterandnegativesequencecomponentfilter.2.3.1概述

Overview电力系统发生不对称短路，故障参数出现负序分量，接地故障出现零序分量，正常运行负、零序分量基本为零。Inthecaseofasymmetricshortcircuitinthepowersystem,negativesequencecomponentappearsinthefaultparameters,andzerosequencecomponentappearsinthegroundfault.Innormaloperation,negativeandzerosequencecomponentsarebasicallyzero.序分量作用：1）利用电流、电压的不对称，判断故障的位置和类型；Functionofsequencecomponent:1)Usetheasymmetryofcurrentandvoltagetojudgethepositionandtypeoffaults;2）利用反映负序、零序分量可构成不对称短路保护。2)Asymmetricshortcircuitprotectioncanbeconstitutedbyreflectingnegativesequenceandzerosequencecomponents.任务二对称分量滤过器Task2SymmetricComponentFilter序分量保护优点：能避开负荷电流，可提高保护灵敏度；不反映系统振荡；能判断故障位置类型；简化保护构成。Sequencecomponentprotectionadvantages:canavoidtheloadcurrent,canimprovetheprotectionsensitivity;

Doesnotreflectsystemoscillation;Beabletodeterminethetypeoffaultlocation;

Simplifyprotectioncomposition.当输入端三相电流、电压中含有三序分量时，输出端只输出零序分量，称为零序分量；只输出负序分量时，称为负序分量滤过器；只输出正序分量时，称为正序分量滤过器。Whenthethree-phasecurrentandvoltageattheinputendcontainthreesequencecomponents,theoutputendonlyoutputszerosequencecomponent,whichiscalledzerosequencecomponent.

Whenonlythenegativesequencecomponentisoutput,itiscalledthenegativesequencecomponentfilter.Whenonlythepositiveordercomponentisoutput,itiscalledthepositiveordercomponentfilter.2.3.2零序分量滤过器

Zero-sequencecomponentfilter任务二对称分量滤过器Task2SymmetricComponentFilter1、零序分量滤过器Zero-sequencecomponentfilter（1）零序电流滤过器Zero-sequencecurrentfilter

根据不对称分量的理论，正序、负序三相仍然对称，其三相相量和等于零。Accordingtothetheoryofasymmetriccomponents,positiveandnegativesequencethreephasesarestillsymmetric,andthesumofthethreephasesisequaltozero.因此：So任务二对称分量滤过器Task2SymmetricComponentFilter

三相并联的输出电流为：Theoutputcurrentofthree-phaseparallelconnectionis任务二对称分量滤过器Task2SymmetricComponentFilter正常运行时：Duringnormaloperation出现不平衡电流原因：互感器励磁电流不对称。Causeofunbalancedcurrent:thetransformerexcitationcurrentisnotsymmetrical.在保护区外发生短路故障时，因短路电流较大，互感器铁芯饱和，不平衡电流要比正常运行时大的多。Whenashortcircuitfaultoccursoutsidetheprotectionzone,duetothelargeshortcircuitcurrentandthesaturationofthetransformercore,theunbalancedcurrentismuchlargerthanthatinnormaloperation.任务二对称分量滤过器Task2SymmetricComponentFilter

(2)零序电压滤过器

Zerosequencevoltagefilter由于三相电压不完全对称，即使不发生接地故障，也有不平衡电压输出。Becausethethree-phasevoltageisnotcompletelysymmetrical,evenifthereisnogroundingfault,thereisanunbalancedvoltageoutput.任务二对称分量滤过器Task2SymmetricComponentFilter

2.3.4负序电压滤过器Negativesequencevoltagefilter滤过器参数关系:Parameterrelationshipoffilter由于相间电压中不存在零序分量，相当于零序分量已被滤掉。因此，负序电压滤过器无一例外地加入相间电压。Sincethereisnozerosequencecomponentinthephasevoltage,thezerosequencecomponenthasbeenfilteredout.

Therefore,thenegativesequencevoltagefilterwithoutexceptionaddsthephasevoltage.任务二对称分量滤过器Task2SymmetricComponentFilter即Thatis任务二对称分量滤过器Task2SymmetricComponentFilter输出为Theoutputis任务二对称分量滤过器Task2SymmetricComponentFilter由于元件参数不准确,阻抗值随温度及频率的影响,加入正序电压时有不平衡电压输出,使用时应注意。Duetotheinaccuracyofcomponentparametersandtheinfluenceofimpedancevaluewithtemperatureandfrequency,theoutputvoltageisunbalancedwhenaddingthepositivesequencevoltage,soitshouldbepaidattentiontowhenusing.如果将负序电压滤过器任意两个输入端互换连接，则滤过器就会成为正序电压滤过器。Ifanytwoinputterminalsofanegativesequencevoltagefilterareinterconnected,thefilterwillbecomeapositivesequencevoltagefilter.任务二对称分量滤过器Task2SymmetricComponentFilter2.3.5负序电流滤过器

Negativesequencecurrentfilter电流变换器的一次绕组匝数关系为：Therelationshipofturnsofprimarywindingofthecurrentconverteris:其目的是消除零序电流的影响。Itspurposeistoeliminatetheeffectofzerosequencecurrent.输出电压为：Theoutputvoltageis任务二对称分量滤过器Task2SymmetricComponentFilter电抗变换器一次两个绕组匝数相等，加入两相电流差。Numberoftwowindingturnsofreactanceconverterisequal,thenaddtwophasecurrentdifference.其二次输出为：Thesecondoutputis加入两相电流差的目的也是为了消除零序分量的影响。Thepurposeofaddingtwo-phasecurrentdifferenceisalsotoeliminatetheeffectofzerosequencecomponent.任务二对称分量滤过器Task2SymmetricComponentFilter负序电流滤过器的输出为：Theoutputofthenegativesequencecurrentfilteris任务二对称分量滤过器Task2SymmetricComponentFilter如果，则无输出。

If

,thereisnooutput.

加入正序分量时：Whenaddingpositivesequencecomponent任务二对称分量滤过器Task2SymmetricComponentFilter加入负序分量时：Whenaddingnegativesequencecomponent输出为

Theoutputis任务二对称分量滤过器Task2SymmetricComponentFilter以上的分析中，没有考虑变换器的角度误差，若计及误差存在，正常运行时有一不平衡分量输出。Intheaboveanalysis,theAngleerroroftheconverterisnottakenintoaccount.Iftheerrorexists,thereisanunbalancedcomponentoutputduringnormaloperation.通常可采取在电流变换器电阻旁并联一个电容，可保证电流变换器输出与电抗变换器输出同相位。Itisusuallypossibletouseacapacitorinparallelwiththecurrentconverterresistortoensurethatthecurrentconverteroutputisinphasewiththereactanceconverteroutput.且二次电压超前电流角度小于。AndthesecondaryvoltageleadcurrentAngleislessthan

.任务二对称分量滤过器Task2SymmetricComponentFilter小结：1)采用序分量滤过器的目的，可以提高保护的灵敏度；Summary:1)thepurposeofusingthesequencecomponentfiltercanimprovethesensitivityofprotection;2)为获得零序分量，只要将三相电流互感器同极性并联，电压顺极性串联；2)Inordertoobtainzerosequencecomponent,aslongasthethree-phasecurrenttransformerisinparallelwiththepolarity,thevoltageisinserieswiththepolarity;3)为了消除零序分量影响，加入负序电压滤过器的电压应为线电压；3)Inordertoeliminatetheinfluenceofzerosequencecomponent,thevoltageofnegativesequencevoltagefiltershouldbelinevoltage;4)必须合理选择参数，才能满足负序分量滤过器的要求；4)Theparametersmustbereasonablyselectedtomeettherequirementsofthenegativesequencecomponentfilter;任务二对称分量滤过器Task2SymmetricComponentFilter5）如果参数失调，可构成复合滤过器；5)Iftheparametersareoutoftune,acompoundfilt