ABB Relion 670 Series Applications Manual page 197

1MRK 511 401-UEN Rev. K
The setting
protection function. The setting is given in degrees. For active power the set angle should be
0° or 180°. 0° should be used for generator low forward active power protection.
IEC06000556 V1 EN-US
Figure 93: 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 79.
=
S 3
N
EQUATION1708 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 k S
EQUATION1893 V1 EN-US
Where
S
S
old
S
Calculated
k
The value of
quite long.
The calibration factors for current and voltage measurement errors are set % of rated current/
voltage:
Bay control REC670
Application manual
Angle1(2) gives the characteristic angle giving maximum sensitivity of the power
Q
Operate
Angle1(2) = 0
Power1(2)
× ×
UBase IBase
Power1(2) + Hysteresis1(2) .
( )
+ - ×
1 k S
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
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°
P
en06000556.vsd
Section 8
Current protection
(Equation 79)
(Equation 80)
191