ABB Relion 670 series - Load Impedance Limitation, with Load Encroachment Function

Set separately the expected fault resistance for the phase-to-ground faults (RFPE) for each
zone. Set all remaining reach setting parameters independently of each other for each
distance zone.
The final reach in resistive direction for phase-to-ground fault loop measurement
automatically follows the values of the line-positive and zero-sequence resistance, and at
the end of the protected zone is equal to equation
216.
R
1
3
---
2 R1PE× R0PE+
( )
RFPE+=
EQUATION567 V1 EN (Equation 216)
2 X1PE +X0
arctan
2 R1PE +R0
loop j
é ù
×
ê ú
=
×
ê ú
ë û
EQUATION1457 V1 EN (Equation 217)
Setting of the resistive reach for the underreaching zone1 should follow the condition:
4.5 1RFPE X£ ×
EQUATION569 V2 EN (Equation 218)
8.5.3.7 Load impedance limitation, without load encroachment function
The following instructions is valid when the load encroachment function is not activated
(OperationLdCmp is set to Off). If the load encroachment function is to be used for all or
some of the measuring zones, the load limitation for those zones according to this chapter
can be omitted. Check the maximum permissible resistive reach for any zone to ensure
that there is a sufficient setting margin between the IED boundary and the minimum load
impedance. The minimum load impedance (Ω/phase) is calculated as:
2
minload
V
Z
S
=
EQUATION1780-ANSI V1 EN (Equation 219)
Where:
V is the minimum phase-to-phase voltage in kV
S is the maximum apparent power in MVA.
The load impedance [Ω/phase] is a function of the minimum operation voltage and the
maximum load current:
Section 8 1MRK 506 369-UUS -
Impedance protection
298 Line distance protection REL670 2.2 ANSI
Application manual