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Digital Current Transformer Reporter. Digital Current Transformer Reporter. DCT-2000. DCT-2000. 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.
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Digital Current Transformer Reporter Digital Current Transformer Reporter DCT-2000 DCT-2000
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.
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
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.
The following screens are common to DCT-2000x2 and DCT-2000x5.
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.