Hitachi Relion 670 Series Applications Manual page 157

1MRK511407-UUS Rev. N
Operate
IEC06000557 V2 EN-US
Figure 74:
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 82.
=
S 3 VBase IBase
N
EQUATION2047 V1 EN-US
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
=
EQUATION1893-ANSI V1 EN-US
Where
S
S
old
S
Calculated
TD
The value of TD=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:
Phasor measurement unit RES670
Application manual
Power 1(2)
For reverse power the set angle should be 180° in the overpower function
× ×
( )
1 TD 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
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Q
o
Angle1(2 ) = 180
IEC06000557-2-en.vsd
Current protection
P
(Equation 82)
(Equation 83)
Section 8
151