Basler BE1-CDS220, Инструкция по эксплуатации

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BE1-CDS220 Protection and Control 4-25
A BLK (Block) logic input is provided to each function that can be used to disable the function. When this
expression is TRUE, the function is disabled by forcing the outputs to logic zero and resetting the timers
to zero. For example, this could be used similar to a torque control contact on an electromechanical relay.
Each inverse time overcurrent function has a pickup, a time dial, and a curve setting. See Appendix A,
Time Overcurrent Characteristic Curves, for details on each of the curves available. To make the
protective element use integrated reset and emulate an electromechanical induction disk reset
characteristic, the user can append an R to the selected time current characteristic curve. A
programmable curve is available that can be used to create a custom curve by selecting coefficients in
the inverse time characteristic equation.
When the measured current is above the pickup threshold, the pickup logic output, 51PPU (for example)
= TRUE and inverse timing is started per the selected characteristic. If the current stays above pickup
until the function times out, the trip logic output, 51PT (for example) = TRUE. If the current falls below the
dropout ratio, which is 95%, the function will either reset instantaneously or begin timing to reset
depending on the user’s setting.
The phase overcurrent protective functions use the highest of the three measured phase currents. If the
current is above the pickup setting for any one phase, the pickup logic output is asserted. If the trip
condition is TRUE, the trip logic output is asserted.
If the target is enabled for the function block, the target reporting function will record a target for all
phases that are above pickup when the protective function 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 details on the target reporting function.
BESTlogic Settings for Time Overcurrent
BESTlogic settings are made from the BESTlogic Function Element screen in BESTCOMS. Figure 4-22
illustrates the BESTCOMS screen used to select BESTlogic settings for the Time Overcurrent function.
To open the screen, select Overcurrent from the Screens pull-down menu and select the 51, 151, or 251
tab. Then select the BESTlogic button that corresponds with the element to be modified. Alternately,
settings may be made using the SL-x51 command (where x = blank, 1, or 2).
Figure 4-22. BESTlogic Function Element Screen, Phase (51P)
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.