ABB Relion 670 series, Руководство по применению, Страница: 300 / 760

R
X
RLdFw
RLdRv
ArgLd
ArgLd ArgLd
ArgLd
IEC09000050-1-en.vsd
IEC09000050 V1 EN-US
Figure 181: Load encroachment characteristic
The load angle
ArgLd is the same in forward and reverse direction, so it could be suitable to
begin to calculate the setting for that parameter. Set the parameter to the maximum possible
load angle at maximum active load. A value bigger than 20° must be used.
The blinder in forward direction, RLdFw, can be calculated according to equation 300 .
2
min
0.8
exp max
U
RLdFw
P
= ×
where:
Pexp max is the maximum exporting active power
Umin
is the minimum voltage for which the Pexp max occurs
0.8 is a security factor to ensure that the setting of RLdFw can be lesser than the calculated minimal
resistive load.
The resistive boundary RLdRv for load encroachment characteristic in reverse direction can be
calculated in the same way as
RLdFw, but use maximum importing power that might occur
instead of maximum exporting power and the relevant Umin voltage for this condition.
7.10.4.2 Minimum operate currents
GUID-5B4DF48C-48ED-433D-92D8-B146E8A8A7E0 v1
FRPSPDIS has two current setting parameters, which blocks the respective phase-to-earth
loop and phase-to-phase loop if the RMS value of the phase current (ILn) and phase difference
current (ILmILn) is below the settable threshold.
The threshold to activate the phase selector for phase-to-earth (
IMinOpPE) is set to the
default value or a level to securely detect a single line-to-earth fault at the furthest reach of the
phase selection. It is recommended to set IMinOpPP to double value of IMinOpPE.
The threshold for opening the measuring loop for phase-to-earth fault ( INReleasePE) is set
securely detect single line-to-earth fault at remote end on the protected line. It is
recommended to set
INBlockPP to double value of INReleasePE.
Section 7 1MRK 505 343-UEN B
Impedance protection
294
Application manual