LineProtectionConfigurationCONTENTSPAGE0102PrincipleoflineprotectionProtectionmodecontrolwordExampleofthelineprotectiondeviceconfigurationPrincipleoflineprotection01CONTENTSPAGE010203CurrentprotectionDistanceprotectionzero-sequenceprotectionPilotprotection04CurrentprotectionconfigurationLineprotectionof66kVandbelowisusuallymainlycurrentprotection,asanalternateshort-circuitprotection,generallyequippedwithtwoorthreesections.Accordingtotheactualcircumstances,adirectionelementoravoltageelementmaybeaddedasalockingelement.DistanceprotectionconfigurationHighvoltagelinesof110kVandaboveareusuallyprovidedwithdistanceprotection,generallywiththreesections.Distanceprotectionisdividedintophasedistanceprotectionandgrounddistanceprotection.Zero-ordercurrentprotectionconfigurationThelargegroundingcurrentsystemof110kVorabovehasazerosequencecomponentinthesystem.Highvoltagelinesof110kVandaboveareusuallyprotectedbyzerosequencecurrentdirectionprotectionasashortcircuittoground,generallyequippedwiththreeorfoursections.Verticalprotectionconfiguration220kVandabovehigh-voltageandultra-high-voltagelines,usually,thepilotprotectionisusedtomeettherequirementofinstantaneousremovaloffaultsacrosstheentireline.Pilotprotectionusuallyincludespilotdistanceprotection,pilotzerosequenceprotectionandpilotdifferentialprotection220kVanahigh-voltageandultra-high-voltagelinesareusuallyequippedwithopticalfiberdifferentialprotectionasthemainprotectionExampleofthelineprotectiondeviceconfiguration0235kVLineprotectiondevice1.Three-stagecurrentprotectionwithdirectionandlowvoltagelock;2.Three-phaserecloseonce;3.Postacceleratedprotection;4.Low-frequencyloadshedding;110kVLineprotectiondevice1.Distanceprotection(phasetophasedistance,phasetoearthdistance(optional));2.Threezonezero-sequencecurrentdirectionprotection(optional);3.Three-phaserecloseonce;4.Postacceleratedprotection;5.Low-frequencyloadshedding;220kVLineprotectiondevice1.Opticalfiberdifferentialprotection2.Distanceprotection(phasetophasedistance,phasetoearthdis