ABB Relion 670 Series Applications Manual page 189

1MRK 511 358-UUS A
IEC06000556 V1 EN-US
Figure 85: 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 75.
=
S
N
EQUATION2047 V1 EN-US
The drop out power will be
The possibility to have low pass filtering of the measured power can be made as shown in the
formula:
S TD S
= ⋅
EQUATION1893-ANSI V1 EN-US
Where
S
S
old
S
Calculated
TD
The value of
long.
Application manual
Q
Operate
Angle1(2) = 0
Power1(2)
× ×
3 VBase IBase
Power1(2) + Hysteresis1(2) .
( )
TD S
+ 1 − ⋅
Old Calculated
is a new measured value to be used for the protection function
is the measured value given from the function in previous execution cycle
is the new calculated value in the present execution cycle
is settable parameter
k = 0.92 is recommended in generator applications as the trip delay is normally quite
°
P
en06000556.vsd
Section 7
Current protection
(Equation 75)
(Equation 76)
183