Basler DECS-200 User Manual

DECS-200 Functional Description 3-15
Oscillography
The data recording function of the DECS-200 can record up to eight oscillography records. Oscillography
records recorded by the DECS-200 use the IEEE Standard Common Format for Transient Data
Exchange (COMTRADE). Each record is time and date stamped. After eight records have been recorded,
the DECS-200 begins recording the next record over the oldest record. Because all oscillography records
are stored in volatile memory, the records will be lost if power is lost.
A record consists of six user selectable variables with 600 data points recorded for each variable. The
sample rate or time between data point samples is user selectable from 4 milliseconds to 10 seconds.
Therefore, the recording duration for a variable can range from 2.4 seconds to 6,000 seconds.
Data points may be selected for pre-trigger operation in order to capture events prior to a fault. Up to 599
pre-trigger data points may be selected. Data points that are not designated for pre-trigger recording are
assigned to the post-trigger portion of the fault record. This feature combined with the adjustable sample
rate allows for flexible data sampling around the fault.
The DECS-200 monitors six user-selectable internal variables. The following internal variables may be
selected:
Internal Variables
• Auto tracking output (for future use)
• Auxiliary input voltage∗
• AVR Error Signal
• Bus frequency
• Bus voltage
• Control output
• Crosscurrent input∗
• Exciter field current Ifd
• Exciter field voltage Vfd
• Generator average L-L voltage
• Generator frequency
• Generator Ib in amps
• Generator kVA
• Generator kvar
• Generator kW
• Generator power factor
• Generator Vab
• Generator Vbc
• Generator Vca
• Generator V-I phase angle∗
• Internal PID Integrator State
∗ Typically, these are used when commissioning or troubleshooting.
Data recording may be triggered manually using BESTCOMS, logic triggers, or level triggers.
Logic triggers allow data recording to occur as a result of an internal or external status change of the
DECS-200.
Level triggering allows the user to select triggering of a data record based on the value of one of the
internal variables. The value can be a minimum or maximum value and can be specified to trigger a
record when the monitored variable crosses a minimum threshold from above or a maximum threshold
from below. A minimum and maximum threshold may also be selected for the monitored variable causing
the monitored value to trigger a record when it goes above its maximum or falls below its minimum.
Figure 3-11 shows an example of a data record as it would look when viewed with BESTwave software.
The example illustrates a voltage step change while monitoring average voltage, field voltage, and field
current over a time period of 2.75 seconds.
For more information about selecting triggering types or levels, selecting internal variables for monitoring
or viewing oscillography records, see Section 5,
BESTCOMS Software .

Basler DECS-200 Specifications

General

Brand	Basler
Model	DECS-200
Category	Controller
Language	English