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Click to edit Master title style
Click to edit Master subtitle styleDCT-2000DCT-2000
Digital Current Transformer Reporter
Digital Current Transformer Reporter
CT Purpose
• To accurately reduce the primary current to a value suitable for relays and meters. (5 or 1 amps).
• Provide isolation from the high voltage system.
Testing and Verification
• NETA -National Electrical Testing Association Recommendations:– Perform polarity test.– Perform ratio-verification test using
voltage or current method– Perform an excitation test.– Measure circuit burden.
Ratio and Polarity
• Ratio must be verified so that relays and meters will operate and indicate correctly.
• Polarity must be correct if relays are to “look” in the correct direction, and for meters to indicate correctly.
Ratio and Polarity Errors
• Taps may have been connected to the wrong terminals or may have been labeled incorrectly.
• Wrong number of turns on CT secondary.
• Shorted turns.• Wrong polarity markings.
Saturation Voltage
• Excitation characteristics and saturation voltage must be known to verify that the CT will perform as required by providing required output voltage during fault conditions.
Excitation of Multi-ratio CT
Typical test circuit of variac volt and amp meters
Time Study
• Time to test 5-tap CT (ten ratios and one excitation curve) with older style equipment for:– Ratio– Polarity and phase-angle– Excitation and Saturation– Winding Resistance– Insulation resistance– Time=52 minutes
With DCT-2000x5, time < 5 minutes
Adwel solution
• The DCT-2000 offers the most advanced features in automated multi-ratio CT testing.
• Product available in two models:– DCT-2000x2– DCT-2000x5 – Test Plan Driven
Key Features of DCT-2000x2
• Automated testing of one winding of a CT for:– Ratio– Polarity and phase-angle– Excitation and Saturation– Winding Resistance– Insulation resistance
DCT-2000x2
Test circuit of x2.
Testing Steps of x2
• Enter windings to be tested• Check-off tests to be preformed• Set a voltage limit• Press test• Observe progress• Save test and go the next
winding
Test Screen for x2 ConfiguredNote: x2 does not have test plan
Key Features of x5
• Same as x2 plus:• Automatically tests up to 5 taps
with operator intervention.• Test plan driven.• Provides the ultimate in CT
testing productivity.
DCT-2000x5
Test circuit of x5.
Test ScreenDriven from the Test Plan
Test Plan
The following screens are common to DCT-2000x2 and DCT-2000x5.
CT Info Screen
Extra Results Details
Extra Results Details
Full Graph Screen
Excitation Table Screen
File Manager
Burden Mode up to 20 amps
Other Features
• Saturation voltage (knee point) is calculated.
• Winding resistance is measured• Insulation resistance is measured• Full 75 key keyboard• Store 200 files.• Store 140 test plans in x5.
Other Features
• Up to 2000 Vac output• Up to 2 amps output• Burden output: 20 amp @ 20 volts• Circuit impedance measurement in
burden mode.• Transfer results to PC with USB• Transfer results to memory stick
PC Based Software
• Results stored in database.– Sort on twelve fields.
• Generate full report form including data and color graphs of all curves.
• Files compatible with word processing and spread sheets.
Modes of Operation
• Auto mode:– Allows DCT to automatically complete a
series of tests.
• Manual mode:– Allows operator to manually raise and lower
the voltage to make diagnosis.
• Burden mode:– Current source for secondary injection
Comparison of models
• Both models have identical features regarding tests, output, range, accuracy, keyboard, printer, memory capacity, memory stick, software and database.
• Differences are listed below.
Test Automation
• X2:– Check boxes on test screen are used
to select the tests to be performed in automatic sequence.
• X5:– A test plan conducts the required
tests on up to ten ratios on a multi-ratio CT. Saves 140 plans.
Extent of Automation
• X2:– Completes all selected tests for one
winding.• X5
– Completes all selected tests for up to ten ratios.
Conclusion
• Contact your local representative or Adwel International for questions or further information.