Basler BE1-CDS220, Инструкция по эксплуатации

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BE1-CDS220 Protection and Control 4-23
Operating Settings for Instantaneous Overcurrent
Operating settings for the 50T functions consist of Pickup and Time delay values. The Pickup value
determines the level of current required for the element to start timing toward a trip. Time delays can be
set in milliseconds, seconds, or cycles. The default is milliseconds if no unit of measure is specified.
Minimum timing resolution is to the nearest one-quarter cycle. A time delay setting of zero makes the
element instantaneous with no intentional time delay.
Operating settings are made using BESTCOMS. Figure 4-20 illustrates the BESTCOMS screen used to
select operational settings for the 50T elements. To open the screen, select Overcurrent from the Screens
pull-down menu. Then select the 50T, 150T, or 250T tab. Alternately, settings may be made using S<g>-
50T ASCII command or through the optional HMI Screens 5.#.3.1 - 5.#.3.3, \PROT\SG#\x50T\.
Figure 4-20. Overcurrent Screen, 50T/150T Tab
The default unit of measure for the Pickup setting is secondary amps. Primary amps (Pri Amps), per unit
amps (Per U Amps), and percent amps (% Amps) can also be selected as the pickup setting unit of
measure. The unit of measure for the Time setting that represents the element's time delay defaults to
milliseconds. It is also selectable for seconds, minutes, and cycles.
If time delay settings are made in cycles, they are converted to seconds or milliseconds (per the nominal
frequency setting stored in EEPROM) before being stored and rounded to the nearest whole millisecond.
See Section 3, Input and Output Functions, Input Current, for more information about this setting. If the
nominal frequency setting is being changed from the default (60 hertz) and time delay settings are being
set in cycles, the frequency setting should be entered and saved before making any time delay settings
changes.
Beside the Logic pull-down menu is a pull-down menu labeled Settings. The Settings menu is used to
select the setting group that the element's settings apply to.
NOTE
If the unit has five ampere phase inputs and a one ampere independent ground
input, the valid pickup setting range of the neutral overcurrent functions will be
dependent upon the logic mode setting which designates whether the three-
phase residual or the independent ground input is to be monitored. If changing
logic schemes or settings causes a neutral overcurrent setting to be OUT OF
RANGE, the out of range setting will be forced in-range by multiplying or dividing
the current setting by five.