ABB REG670 - Page 295

tZ1: tZ1 is the setting of trip delay for Z1 and this parameter is recommended to set 0.1
s.
© ABB Group
June 21, 2010 | Slide 1
IEC10000201-1-en.vsd
IEC10000201 V1 EN
Figure 152: Loss of excitation characteristics recommended by IEEE
It is recommended to set XoffsetZ2 equal to - X
d
'/2 and Z2diamater equal to X
d
.
tZ2: tZ2 is the setting of trip delay for Z2 and this parameter is recommended to set 2.0
s not to risk unwanted trip at oscillations with temporary apparent impedance within
the characteristic.
DirSuperv: The directional restrain characteristic allows impedance setting with
positive X value without the risk of unwanted operation of the under-excitation
function. To enable the directional restrain option the parameter DirSuperv shall be set
On.
XoffsetDirLine, DirAngle: The settings XoffsetDirLine and DirAngle are shown in
figure
153. XoffsetDirLine is set in % of the base impedance according to
equation 171.
XoffsetDirLine is given a positive value if X > 0. DirAngle is set in degrees with
negative value in the 4
th
quadrant. Typical value is -13°.
1MRK 502 071-UEN - Section 8
Impedance protection
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 289
Application manual