Basler BE1-CDS220, Instruction Manual

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13-26 Testing And Maintenance BE1-CDS220
In-Service Current Circuit Verification Form
Time and Date:
Station ID: Relay ID:
User1 ID: User2 ID:
Trigger Differential Check Record
To trigger and retrieve a current check record, use the following commands:
A=
RA-DIFF=TRIG
RA-DIFF
Examine Differential Check Record
1. Examine the Measurements portion of the report. Plot on the appropriate polar graph, the currents
under the differential check record lines Measured I Pri and Tap Comp I for each phase and CT input
circuit.
90°
0°
180°
270°
0°
90°
0°
180°
270°
120°
150°
210°
240° 300°
330°
30°
60°
120°
150°
210°
240° 300°
330°
30°
60°
D2558-14.cdr
07-18-00
Plot Primary Currents Plot Compensated Currents
2. Examine the plotted currents.
— Is the phase sequence for both CT circuits the same as expected?
— Does the phase sequence match the phase sequence setting (SG-PHROT) or HMI screen 6.3.3?
— Examine the angle and tap compensated currents on the polar graph from the line labeled Tap
Comp I. For each phase, determine if the currents are approximately the same magnitude for
each CT input circuit and approximately 180 degrees out of phase? Some small amount of
mismatch is expected due to excitation and possible LTC or other tap adjust differences.
3. Examine the Alarms portion of the report.
— The line marked Differential will report Alarm for any phase where the differential current is above
the alarm threshold on that phase.
— The lines marked Polarity, Angle Comp, and Mismatch will report Alarm or OK as determined by
the current circuit diagnostic function if the currents are above the minimum sensitivity. The
diagnostic function for these lines operates even if the differential current is not above the alarm
threshold.