ABB REL670 2.2 IEC Applications Manual page 525

1MRK 506 369-UEN B
Line distance protection REL670 2.2 IEC
Application manual
Operate
Angle1(2) = 0
Power1(2)
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.
= × ×
S 3 UBase IBase
N
EQUATION1708 V1 EN-US
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:
( )
= × + - ×
S k S 1 k S
Old Calculated
EQUATION1893 V1 EN-US
Where
S is a new measured value to be used for the protection function
S is the measured value given from the function in previous execution cycle
old
S is the new calculated value in the present execution cycle
Calculated
k
is settable parameter
Q
°
en06000556.vsd
Section 9
Current protection
P
(Equation 495)
(Equation 496)
519