項目二繼電保護基本元件Project2BasiccomponentsofRelayProtection

課程負責人：關嬌嬌張勇CourseLeader：GuanJiaojiaoZhangYong

課程負責人：關嬌嬌張勇CourseLeader：GuanJiaojiaoZhangYong任務二對稱分量濾過器Task2SymmetricComponentFilter教學要求:掌握零序分量濾過器、負序分量濾過器工作原理以及分析方法。Teachingrequirements:mastertheworkingprincipleandanalysismethodofzero-sequencecomponentfilterandnegativesequencecomponentfilter.2.3.1概述

Overview電力系統發生不對稱短路，故障參數出現負序分量，接地故障出現零序分量，正常運行負、零序分量基本為零。Inthecaseofasymmetricshortcircuitinthepowersystem,negativesequencecomponentappearsinthefaultparameters,andzerosequencecomponentappearsinthegroundfault.Innormaloperation,negativeandzerosequencecomponentsarebasicallyzero.序分量作用：1）利用電流、電壓的不對稱，判斷故障的位置和類型；Functionofsequencecomponent:1)Usetheasymmetryofcurrentandvoltagetojudgethepositionandtypeoffaults;2）利用反映負序、零序分量可構成不對稱短路保護。2)Asymmetricshortcircuitprotectioncanbeconstitutedbyreflectingnegativesequenceandzerosequencecomponents.任務二對稱分量濾過器Task2SymmetricComponentFilter序分量保護優點：能避開負荷電流，可提高保護靈敏度；不反映系統振蕩；能判斷故障位置類型；簡化保護構成。Sequencecomponentprotectionadvantages:canavoidtheloadcurrent,canimprovetheprotectionsensitivity;

Doesnotreflectsystemoscillation;Beabletodeterminethetypeoffaultlocation;

Simplifyprotectioncomposition.當輸入端三相電流、電壓中含有三序分量時，輸出端只輸出零序分量，稱為零序分量；只輸出負序分量時，稱為負序分量濾過器；只輸出正序分量時，稱為正序分量濾過器。Whenthethree-phasecurrentandvoltageattheinputendcontainthreesequencecomponents,theoutputendonlyoutputszerosequencecomponent,whichiscalledzerosequencecomponent.

Whenonlythenegativesequencecomponentisoutput,itiscalledthenegativesequencecomponentfilter.Whenonlythepositiveordercomponentisoutput,itiscalledthepositiveordercomponentfilter.2.3.2零序分量濾過器

Zero-sequencecomponentfilter任務二對稱分量濾過器Task2SymmetricComponentFilter1、零序分量濾過器Zero-sequencecomponentfilter（1）零序電流濾過器Zero-sequencecurrentfilter

根據不對稱分量的理論，正序、負序三相仍然對稱，其三相相量和等于零。Accordingtothetheoryofasymmetriccomponents,positiveandnegativesequencethreephasesarestillsymmetric,andthesumofthethreephasesisequaltozero.因此：So任務二對稱分量濾過器Task2SymmetricComponentFilter

三相并聯的輸出電流為：Theoutputcurrentofthree-phaseparallelconnectionis任務二對稱分量濾過器Task2SymmetricComponentFilter正常運行時：Duringnormaloperation出現不平衡電流原因：互感器勵磁電流不對稱。Causeofunbalancedcurrent:thetransformerexcitationcurrentisnotsymmetrical.在保護區外發生短路故障時，因短路電流較大，互感器鐵芯飽和，不平衡電流要比正常運行時大的多。Whenashortcircuitfaultoccursoutsidetheprotectionzone,duetothelargeshortcircuitcurrentandthesaturationofthetransformercore,theunbalancedcurrentismuchlargerthanthatinnormaloperation.任務二對稱分量濾過器Task2SymmetricComponentFilter

(2)零序電壓濾過器

Zerosequencevoltagefilter由于三相電壓不完全對稱，即使不發生接地故障，也有不平衡電壓輸出。Becausethethree-phasevoltageisnotcompletelysymmetrical,evenifthereisnogroundingfault,thereisanunbalancedvoltageoutput.任務二對稱分量濾過器Task2SymmetricComponentFilter

2.3.4負序電壓濾過器Negativesequencevoltagefilter濾過器參數關系:Parameterrelationshipoffilter由于相間電壓中不存在零序分量，相當于零序分量已被濾掉。因此，負序電壓濾過器無一例外地加入相間電壓。Sincethereisnozerosequencecomponentinthephasevoltage,thezerosequencecomponenthasbeenfilteredout.

Therefore,thenegativesequencevoltagefilterwithoutexceptionaddsthephasevoltage.任務二對稱分量濾過器Task2SymmetricComponentFilter即Thatis任務二對稱分量濾過器Task2SymmetricComponentFilter輸出為Theoutputis任務二對稱分量濾過器Task2SymmetricComponentFilter由于元件參數不準確,阻抗值隨溫度及頻率的影響,加入正序電壓時有不平衡電壓輸出,使用時應注意。Duetotheinaccuracyofcomponentparametersandtheinfluenceofimpedancevaluewithtemperatureandfrequency,theoutputvoltageisunbalancedwhenaddingthepositivesequencevoltage,soitshouldbepaidattentiontowhenusing.如果將負序電壓濾過器任意兩個輸入端互換連接，則濾過器就會成為正序電壓濾過器。Ifanytwoinputterminalsofanegativesequencevoltagefilterareinterconnected,thefilterwillbecomeapositivesequencevoltagefilter.任務二對稱分量濾過器Task2SymmetricComponentFilter2.3.5負序電流濾過器

Negativesequencecurrentfilter電流變換器的一次繞組匝數關系為：Therelationshipofturnsofprimarywindingofthecurrentconverteris:其目的是消除零序電流的影響。Itspurposeistoeliminatetheeffectofzerosequencecurrent.輸出電壓為：Theoutputvoltageis任務二對稱分量濾過器Task2SymmetricComponentFilter電抗變換器一次兩個繞組匝數相等，加入兩相電流差。Numberoftwowindingturnsofreactanceconverterisequal,thenaddtwophasecurrentdifference.其二次輸出為：Thesecondoutputis加入兩相電流差的目的也是為了消除零序分量的影響。Thepurposeofaddingtwo-phasecurrentdifferenceisalsotoeliminatetheeffectofzerosequencecomponent.任務二對稱分量濾過器Task2SymmetricComponentFilter負序電流濾過器的輸出為：Theoutputofthenegativesequencecurrentfilteris任務二對稱分量濾過器Task2SymmetricComponentFilter如果，則無輸出。

If

,thereisnooutput.

加入正序分量時：Whenaddingpositivesequencecomponent任務二對稱分量濾過器Task2SymmetricComponentFilter加入負序分量時：Whenaddingnegativesequencecomponent輸出為

Theoutputis任務二對稱分量濾過器Task2SymmetricComponentFilter以上的分析中，沒有考慮變換器的角度誤差，若計及誤差存在，正常運行時有一不平衡分量輸出。Intheaboveanalysis,theAngleerroroftheconverterisnottakenintoaccount.Iftheerrorexists,thereisanunbalancedcomponentoutputduringnormaloperation.通常可采取在電流變換器電阻旁并聯一個電容，可保證電流變換器輸出與電抗變換器輸出同相位。Itisusuallypossibletouseacapacitorinparallelwiththecurrentconverterresistortoensurethatthecurrentconverteroutputisinphasewiththereactanceconverteroutput.且二次電壓超前電流角度小于。AndthesecondaryvoltageleadcurrentAngleislessthan

.任務二對稱分量濾過器Task2SymmetricComponentFilter小結：1)采用序分量濾過器的目的，可以提高保護的靈敏度；Summary:1)thepurposeofusingthesequencecomponentfiltercanimprovethesensitivityofprotection;2)為獲得零序分量，只要將三相電流互感器同極性并聯，電壓順極性串聯；2)Inordertoobtainzerosequencecomponent,aslongasthethree-phasecurrenttransformerisinparallelwiththepolarity,thevoltageisinserieswiththepolarity;3)為了消除零序分量影響，加入負序電壓濾過器的電壓應為線電壓；3)Inordertoeliminatetheinfluenceofzerosequencecomponent,thevoltageofnegativesequencevoltagefiltershouldbelinevoltage;4)必須合理選擇參數，才能滿足負序分量濾過器的要求；4)Theparametersmustbereasonablyselectedtomeettherequirementsofthenegativesequencecomponentfilter;任務二對稱分量濾過器Task2SymmetricComponentFilter5）如果參數失調，可構成復合濾過器；5)Iftheparametersareoutoftune,acompoundfilt