ABB Relion REC670 - 7.14 Broken conductor check BRCPTOC; 7.15 Capacitor bank protection CBPGAPC

Operate
Angle1(2) = 0 °
Power1(2)
P
Q
en06000556.vsd
IEC06000556 V1 EN-US
Figure 72: 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.
3
N
S UBase IBase= × ×
EQUATION1708 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:
( )
1
Old Calculated
S k S k S= × + - ×
EQUATION1893 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
k is settable parameter
The value of k = 0.92 is recommended in generator applications as the trip delay is normally
quite long.
The calibration factors for current and voltage measurement errors are set % of rated current/
voltage:
IAmpComp5, IAmpComp30, IAmpComp100
1MRK 511 358-UEN A Section 7
Current protection
157
Application manual