Table of Contents
Foreword
Section1General
1.1Scope
1.2ReferencedStandards
1.2.1Otherreferences
Section2Introduction
2.1ArcingGroundFaults
2.2NeedforGroundFaultProtection
2.3Standards
2.4Application-General
2.5RelaySettingSelections-General
2.6MethodsOfGFPDeviceSelectivity
2.7DamageLevels
Section3PowerCircuit
3.1Voltage
3.2Frequency
3.3CurrentRating
3.4LocationOfGroundFaultSensingDevices
3.4.1GroundReturnMethod
3.4.2OutgoingCircuitMethod(ResidualorZero-Sequence)
3.5GroundConnections
3.6MountingAndConnectionofGroundFaultSensingDevices
3.7DeltaConnectedSystems
3.8NeutralsandGrounding
3.9NeedforCompleteSystemInformation
3.10SystemsContainingTransformers
3.11SystemDesign
Section4ControlCircuit
4.1ControlPower
4.2ACControlPower
4.3DCControlPower
4.4ControlCircuitProtection
4.5ControlWiring
4.6IndicationandTestCircuits
4.7CompatibilityofGFPDevices
Section5TypicalApplicationDiagrams
5.1General
5.1.1Abbreviations
5.2GroundFaultProtectiononMainDisconnectOnly-Ground
ReturnType
5.3GroundFaultProtectiononMainDisconnectOnly-Outgoing
CircuitType
5.4GroundFaultProtectiononMainandFeederDisconnects-
GroundReturnTypeonMain
5.5GroundFaultProtectiononMainandFeederDisconnects-
OutgoingCircuitTypeonMain
5.6GroundFaultProtectiononMainandFeederDisconnects
WithZoneSelectiveInterlocking-GroundReturnType
onMain
5.7GroundFaultProtectiononMain,Feeders,andSelected
BranchDisconnectswithZoneSelectiveInterlocking-
OutgoingCircuitTypeonMain
5.8Double-EndedSystemwithGroundFaultProtectiononMains,
TieandFeederDisconnects-GroundReturnTypeonMains
Section6TimeandCurrentSettings
6.1ApplicationofGroundFaultProtectiveSystemsfor
CoordinatedGroundFaultTripping
6.2TypesofCoordinatedGroundFaultTrippingSystems
6.3Time-CurrentBandSelectiveSystem
6.4ZoneSelectiveSystem
6.5CoordinationofLow-VoltageDisconnectswiththeHigh-Voltage
SideofaSystem
6.6CoordinationwithDownstreamOvercurrentDevicesNot
EquippedwithGroundFaultProtection
6.7TypicalSettings
6.7.1SingleZone-GroundFaultProtectiononMainDisconnect
Only
6.7.2MultipleZoneTimeCurrentBandSelectiveSystem-
GroundFaultProtectiononMains,Feeder,andBranch
Circuits
6.7.3ZoneSelectiveSystem-GroundFaultProtectionon
MainsandFeeders
Section7TypicalCoordinatedSystems
7.1CoordinatedProtection
7.2Examples
7.2.1GFPonMainDisconnectOnly
7.2.2GFPonMainDisconnectandFeeders
7.2.3FullyCoordinatedMultipleZoneGroundFault
ProtectionSystems
Section8TestingOfGroundFaultSensingandRelayingEquipment
8.1DesignTests
8.2ProductionTests
8.3TestsonAssembledEquipment
8.4PreparationForFieldTesting
8.5FieldTesting
AppendixAArcingFaultDamageLevels
A.1ApproximateArcingFaultDamageLevelsfor480Y/277Volt
Systems
A.2ArcingFaultCurrent
A.3AssumedTolerableDamageLevels
A.4ProbableAmountofDamage
AppendixBSystemDesignConsiderations
B.1General
B.2PowerSystem
B.3GroundFaultCurrentPaths
B.4GroundFaultProtectiveDevicesandSettings
B.5ControlPower Abstract
Provides practical information containing instructions for the safe and proper application of ground fault protective (GFP) devices.
