8.1.3.7 Setting of reach in resistive direction
Set the resistive reach independently for each zone, and separately for phase-to-phase
(R1PP), and phase-to-ground loop (R1PG) measurement.
Set separately the expected fault resistance for phase-to-phase faults (R1PP) and for the
phase-to-ground faults (RFPG) 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
86.
1
R (2 R1PG R0PG) RFPG
3
= × + +
EQUATION1716 V1 EN (Equation 86)
2 X1PE+X0
arctan
2 R1PE+R0
loop
j
é ù
×
ê ú
=
×
ê ú
ë û
EQUATION1457 V1 EN (Equation 87)
Setting of the resistive reach for the underreaching zone1 must follow the following
condition:
EQUATION1717 V1 EN (Equation 88)
The fault resistance for phase-to-phase faults is normally quite low, compared to the fault
resistance for phase-to-ground faults. Limit the setting of the zone1 reach in resistive
direction for phase-to-phase loop measurement to:
EQUATION570 V2 EN (Equation 89)
8.1.3.8 Load impedance limitation, without load encroachment function
The following instructions is valid when the load encroachment function is not activated,
which is done by setting the parameter Rld for the Phase Selector to its upper limit. 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:
Section 8 1MRK 506 369-UUS -
Impedance protection
212 Line distance protection REL670 2.2 ANSI
Application manual
To Next Page
Loading...
