Basler Electric BE1-700 - Manual (Page 77)

1.001. The overall inverse time delay range is limited to 1,000 seconds maximum and 0.2 seconds
minimum.
n
Nominal
Measured
T
T
1
V/Hz
V/Hz
D
T






−
=
100 *
FST
E
* D T
T
R R
=
Equation 4-5. Time to Trip Equation 4-6. Time to Reset
where:
T
T
= Time to trip
T
R
= Time to reset
D
T
= Time dial trip
D
R
= Time dial, reset
E
T
= Elapsed time
n = Curve exponent (0.5, 1, 2)
FST = Full scale trip time (T
T
)
E
T
/FST = Fraction of total travel toward trip that integration had progressed to. (After a trip,
this value will be equal to one.)
When the measured V/Hz rises above a pickup threshold, the pickup element becomes TRUE and an
integrating or definite time timer starts. If the V/Hz remains above the pickup threshold and the integration
continues for the required time interval as defined by the equations shown above and the set time dial,
the trip output becomes TRUE. But if the measured V/Hz condition falls below the pickup setting and
integrating reset is chosen, the integrating trip timer will ramp down towards reset at a linear rate based
on the reset time dial setting. See Appendix D, Overexcitation (24) Inverse Time Curves, for details on
each of the available time curves.
If the target is enabled for the 24 element, the target reporting function will record a target when the trip
output is TRUE and the fault recording function trip logic expression is TRUE. See Section 6, Reporting
and Alarm Functions, Fault Reporting, for more information about target reporting.
BESTlogic Settings for Overexcitation Protection
BESTlogic settings are made from the BESTlogic Function Element screen in BESTCOMS. Figure 4-16
illustrates the BESTCOMS screen used to select BESTlogic settings for the Overexcitation (24) element.
To open the BESTlogic Function Element screen for Overexcitation (24), select Voltage Protection from
the Screens pull-down menu and select the 24 tab. Then, select the BESTlogic button. Alternately,
settings may be made using SL-24 ASCII command.
At the top center of the BESTlogic Function Element screen is a pull-down menu labeled Logic. This
menu allows viewing of the BESTlogic settings for each preprogrammed logic scheme. A custom logic
scheme must be created and selected in the Logic pull-down menu at the top of the screen before
BESTlogic settings can be changed. See Section 7, BESTlogic Programmable Logic.
Enable the BESTlogic function by selecting its mode of operation from the Mode pull-down menu. To
connect the function/elements inputs, select the button for the corresponding input in the BESTlogic
Function Element screen. The BESTlogic Expression Builder screen will open. Select the expression type
to be used. Then, select the BESTlogic variable, or series of variables to be connected to the input.
Select Save when finished to return to the BESTlogic Function Element screen. For more details on the
BESTlogic Expression Builder, See Section 7, BESTlogic Programmable Logic. Select Done when the
settings have been completely edited.
9376700990 Rev M BE1-700 Protection and Control 4-21