9328900990 Rev L BE1-951 Time Overcurrent Characteristic Curves A-5
When curve 46 is selected, the relay changes the range of the allowed time dial to 1 to 99 (instead of the
time dial range of 0.1 to 9.9 for all the other curves). The user should enter the “K” factor of the generator
into the time dial field.
Relay Equation
When the 46 function is used, the relay uses the K factor (i.e., 46 time dial setting), 46 minimum pickup
setting, and generator full-load current to create a constant Z (see Equation A-4).
2
SettingPickup46
Setting Nom
I
DialTime46Z
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
Equation A-4
The time to trip equation used in the relay is:
seconds0.028
M
Z
T
2
T
+=
Equation A-5
where
SettingPickup46
IMeasured
M
2
=
Equation A-6
which, when M > 1, reduces to:
2
Measured
2
I
Setting Nom
I
DialTime46
T
T
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
Equation A-7
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