ABB Relion 670 series, Technical Reference Manual

Page: 355 / 1232

6.11.2.1 Resistive reach in forward direction
To avoid load encroachment, the resistive reach is limited in forward direction by
setting the parameter
RLdOutFw which is the outer resistive load boundary value while
the inner resistive boundary is calculated according to equation 74 .
RLdInFw = kLdRFw·RLdOutFw
EQUATION1185 V2 EN
(Equation 74)
where:
kLdRFw is a settable multiplication factor less than 1
The slope of the load encroachment inner and outer boundary is defined by setting the
parameter
LdAngle .
The load encroachment in the fourth quadrant uses the same settings as in the first
quadrant (same
LdAngle and RLdOutFw and calculated value RLdInFw).
The quadrilateral characteristic in the first quadrant is tilted to get a better adaptation to
the distance measuring zones. The angle is the same as the line angle and derived from
the setting of the reactive reach inner boundary
X1InFw and the line resistance for the
inner boundary R1LIn . The fault resistance coverage for the inner boundary is set by
the parameter R1FInFw .
From the setting parameter RLdOutFw and the calculated value RLdInFw a distance
between the inner and outer boundary,
D
Fw, is calculated. This value is valid for R
direction in first and fourth quadrant and for X direction in first and second quadrant.
6.11.2.2 Resistive reach in reverse direction
To avoid load encroachment in reverse direction, the resistive reach is limited by
setting the parameter
RLdOutRv for the outer boundary of the load encroachment zone.
The distance to the inner resistive load boundary RLdInRv is determined by using the
setting parameter
kLdRRv in equation 75 .
RLdInRv = kLdRRv·RLdOutRv
EQUATION1187 V2 EN
(Equation 75)
where:
kLdRRv is a settable multiplication factor less than 1
1MRK505222-UUS C
Section 6
Impedance protection
349
Technical reference manual