ABB REL670 2.2 IEC - Page 525

Operate
Angle1(2) = 0 °
Power1(2)
P
Q
en06000556.vsd
IEC06000556 V1 EN-US
Figure 282: For low forward power the set angle should be 0° in the
underpower function
TripDelay1(2) is set in seconds to give the time delay for trip of the stage after pick
up.
Hysteresis1(2) is given in p.u. of generator rated power according to equation 495.
3
N
S UBase IBase= × ×
EQUATION1708 V1 EN-US
(Equation 495)
The drop out power will be Power1(2) + Hysteresis1(2).
The possibility to have low pass filtering of the measured power can be made as
shown in the formula:
( )
1
Old Calculated
S k S k S= × + - ×
EQUATION1893 V1 EN-US (Equation 496)
Where
S is a new measured value to be used for the protection function
S
old
is the measured value given from the function in previous execution cycle
S
Calculated
is the new calculated value in the present execution cycle
k is settable parameter
1MRK 506 369-UEN B Section 9
Current protection
Line distance protection REL670 2.2 IEC 519
Application manual