ABB Relion REC670, Applications Manual

Page: 225 / 658

Operate
Angle1(2) = 0
°
Power1(2)
P
Q
en06000556.vsd
IEC06000556 V1 EN-US
Figure 88: 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 74 .
N
S 3 VBase IBase
= × ×
EQUATION2047 V1 EN-US
(Equation 74)
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
Old Calculated
= ⋅ + −
( )
⋅
1
EQUATION1893-ANSI V1 EN-US
(Equation 75)
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
TD is settable parameter
1MRK 511 401-UUS A
Section 8
Current protection
Bay control REC670 2.2 ANSI 219
Application manual