TimelimitProtectionofCurrentBreak限时过流保护

项目三输电线路的电流电压保护Project3:CurrentandVoltageProtectionofTransmissionLines任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak1、限时电流速断保护原理和整定计算Protectionprincipleandsettingcalculationoftime-limitedcurrentbreak要求：应能保护线路全长。Requirements:shouldbeabletoprotectthefulllengthoftheline.被保护线路末端短路有灵敏度，必然保护区要延伸到相邻线路、或相邻元件的一部分。Ashortcircuitattheendofaprotectedlineissensitive,sotheprotectionzonemustextendtoanadjacentlineorpartofanadjacentcomponent.

为满足选择性要求，保护动作带有一定的时限。Inordertomeettheselectiverequirements,theprotectionactionhasacertaintimelimit.图形符号Graphicsymbol＞任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak为满足选择性、快速性，动作电流必须大于相邻无时限电流线路速断保护。Inordertosatisfytheselectivityandrapidity,theoperatingcurrentmustbegreaterthanthespeedbreakprotectionoftheadjacentuntimedcurrentline.任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak保护动作电流为：Protectionactioncurrentis1）与相邻线路配合

Cooperatewithadjacentlines2）与相邻变压器配合

Matchwithadjacenttransformer可靠系数取

配合系数取Thereliabilitycoefficientissetto；Thefitcoefficientissetto任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak为满足选择性要求，保护动作时间必须与相邻线路、元件配合，即Inordertomeettheselectivityrequirements,theprotectionactiontimemustbematchedwithadjacentlinesandcomponents,i.e

时限级差，一般取范围内，微机保护可取小值。Timedifference

,generallytake0.3S-0.5Srange,

microcomputerprotectiondesirablesmallvalue.任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak动作时间配合：Cooperatewithactingtime任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak取大值为保护1动作时间。Themaximumvalueisactiontimeofprotection1.灵敏度：Senstivity≥任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak当灵敏度不满足要求时,可与相邻线路的限时电流速断保护配合。Whenthesensitivitydoesnotmeettherequirements,itcanbematchedwiththetime-limitedcurrentbreak-offprotectionofadjacentlines.原理接线：Principleconnection任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak小结：Summary（1）无时限电流速断保护只能保护线路的一部分，动作的选择性依靠动作值来保证。对于线路变压器组，可使全线处于速动保护范围之内。Untimedcurrentbreakprotectioncanonlyprotectapartoftheline,andtheselectivityoftheactiondependsontheactionvaluetoensure.

Forlinetransformergroup,thewholelinecanbewithintherangeofquickactionprotection.（2）无时限电流速断保护的灵敏度以保护区的长度来确定。Thesensitivityofuntimedcurrentbreakprotectionisdeterminedbythelengthoftheprotectionzone.（3）限时电流速断保护作为线路的主保护，要求应能保护被保护线路全长。为了缩短保护的动作时间，动作值与相邻线路、元件速断保护配合。Asthemainprotectionoftheline,itisrequiredtoprotectthewholelengthoftheprotectedline.

Inordertoshortentheactiontimeofprotection,theactionvalueismatchedwiththespeedbreakprotectionofadjacentlinesandcomponents.任务二限时电流速断保护Task2:Time-limitProtectionofCurrentBreak（4）限时电流速断保护的选择性是依靠动作值、动作时间来保证。Theselectivityoftime-limitedcurrentflowbreakprotectiondependsontheactionvalueandactiontime.（5）当灵敏度不满足要求时，可与相邻线路限时电流速断保护配合。Whenthesensitivitydoesnot