ABB ret650, Technical Manual

Page: 134 / 670

argument of the tilted lines outside the load encroachment is the same as the tilted lines
in the first quadrant. The distance between the inner and outer boundary is the same
as for the load encroachment in reverse direction, that is
D
Rv.
7.1.6.3 Reactive reach in forward and reverse direction
The inner characteristic for the reactive reach in forward direction correspond to the
setting parameter
X1InFw and the outer boundary is defined as X1InFw +
D
Fw,
where:
D Fw =
RLdOutFw - KLdRFw · RLdOutFw
The inner characteristic for the reactive reach in reverse direction correspond to the
setting parameter
X1InRv for the inner boundary and the outer boundary is defined as
X1InRv +
D
Rv.
where:
D Rv =
RLdOutRv - KLdRRv · RLdOutRv
7.1.6.4 Basic detection logic
The operation of the Power swing detection ZMRPSB is only released if the
magnitude of the current is above the setting of the min operating current,
IMinOpPE .
• The 1 out of 3 operating mode is based on detection of power swing in any of the
three phases. Figure 52 presents a composition of an internal detection signal
DET-L1 in this particular phase.
Signals ZOUTLn (outer boundary) and ZINLn (inner boundary) in figure 52 are
related to the operation of the impedance measuring elements in each phase separately
(
n represents the corresponding L1, L2 and L3). They are internal signals, calculated
by ZMRPSB function.
The tP1 timer in figure 52 serve as detection of initial power swings, which are usually
not as fast as the later swings are. The tP2 timer become activated for the detection of
the consecutive swings, if the measured impedance exit the operate area and returns
within the time delay, set on the
tW waiting timer. The upper part of figure 52 (internal
input signal ZOUTL1, ZINL1, AND-gates and tP-timers) are duplicated for phase L2
and L3. All
tP1 and tP2 timers in the figure have the same settings.
Section 7
1MRK 504 135-UEN A
Impedance protection
128
Technical manual