ABB RET670 Applications Manual page 488

Section 3
IED application
482
Operate
Angle1(2) = 0
Power1(2)
IEC06000556 V1 EN
Figure 207: 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 381.
= × ×
S 3 VBase IBase
N
EQUATION2047 V1 EN
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 TD S TD S
= ⋅ + 1 − ⋅
Old Calculated
EQUATION1893-ANSI V1 EN
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
TD
is settable parameter
Q
°
en06000556.vsd
1MRK504116-UUS C
P
(Equation 381)
(Equation 382)
Application manual