Under Voltage Seal-In - ABB REG670 Applications Manual

Section 8
Impedance protection
8.9.3.3
316
The load angle ArgLd is same in forward and reverse direction, so it is suitable to begin
the calculation of the parameter setting. The parameter is set to the maximum possible
load angle at the maximum active load. A value larger than 20° must be used.
The blinder RLd can be calculated according to the equation
æ
U
= × ×
RLd ç 0.8 U min
min
è P
exp max
GUID-AF9BD6F2-E64B-424D-B361-49448A1CF690 V2 EN
Where,
Pexpmax
is the maximum exporting active power
Umin
is the minimum voltage for which
0.8
is the security factor to ensure that the setting of
minimal resistive load
Load encroachment characteristic
ArgLd
-RLd
ArgLd
IEC11000304 V1 EN
Figure 167: Characteristics of load encroachment in R-X plane

Under voltage seal-in

Settings involved in under voltage seal-in are:
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
ö
÷
ø
Pexpmax occurs
jX
ArgLd
R
RLd
ArgLd
IEC11000304_1_en
1MRK 502 071-UEN -
174
(Equation 174)
RLd can be lesser than the calculated
Application manual