Earth-fault protection offering


Protection function	REX640	REX615	REX610	630 series	620 series	615 series	REF601	SSC600
Feeders
Non-directional, low stage	■	■	■	■	■	■	■	■
Non-directional, high stage	■	■	■	■	■	■	■	■
Non-directional, instantaneous stage	■	■	■	■	■	■		■
Directional, low stage	■	■	■	■	■	■		■
Directional, high stage	■	■	■	■	■	■		■
Admittance-based	■	■		■	■	■		■
Multifrequency admittance-based	■	■		■	■	■		■
Wattmetric-based	■	■		■	■	■		■
Transient/intermittent-based	■	■			■	■		■
Harmonics-based	■	■			■	■
Touch voltage-based	■	■
Residual over voltage-based	■	■	■	■	■	■		■
Transformers and machines
High impedance-based restricted	■	■		■	■	■
Low impedance-based restricted	■	■		■	■	■		■
Injection method for rotor	■	■		■
Third harmonic-based for stator	■	■		■		■

Applicability to different neutral earthing principles

	Protection function
	Current-based	Power-based	Admittance-based	Transient-based	Multi-frequency	Touch voltage-based
Neutral earthing principle	DEFxPDEF	WPWDE	EFPADM	INTRPTEF	MFADPSDE	IFPTOC
Isolated, unearthed	■ IoSin, Ph.angle φ=-90°	■ φ=-90°	■ B₀	(■)	■	■
Compensated, Petersen coil¹	■ IoCos, Ph.angle φ=0°	■ φ=0°	■ G₀ & B₀	■	■	■
Resistor (high ohmic)	■ IoCos, Ph.angle φ=-45°	■ φ=≈-45°	■ G₀	(■)	■	■
Resistor (low ohmic)	■ Ph.angle φ=≈+45°	O	O	O	O	O
Solid, effectively earthed	■ Ph.angle φ=≥+45°	O	O	O	O	O

1. In a compensated network, the operation is based on the resistive part of operating quantity, which is very sensitive to current transformer errors. It is therefore recommended that a core balance CT is used for measuring the residual current.
■ = Applicable, preferred
(■) = Applicable
O = Not applicable

Earth-fault protection offering

Applicability to different neutral earthing principles

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