Operate
Angle1(2 ) = 180
o
Power1(2)
P
Q
IEC06000557-2-en.vsd
IEC06000557 V2 EN
Figure 71: For reverse power the set angle should be 180° in the overpower
function
TripDelay1(2) is set in seconds to give the time delay for trip of the stage after pick up.
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 (Equation 55)
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=0.98 or even k=0.99 is recommended in generator reverse power
applications as the trip delay is normally quite long. This filtering will improve
accuracy of the power function.
Section 6 1MRK 505 291-UEN A
Current protection
148
Application manual
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