Vanguard EZCT-2000C Plus - Manual (Page 6)

EZCT-2000C USER’S MANUAL REV 1
2
1.0 INTRODUCTION
1.1 General Description and Features
The EZCT-2000C is Vanguard’s third-generation microprocessor-based current transformer test
set. The EZCT-2000C is available in two models, the EZCT-2000C and EZCT-2000C Plus. Designed
specifically for CT testing, the EZCT-2000C has the following outstanding features that can
greatly increase productivity and save time during the commissioning stage:
• Performs CT excitation, current-ratio, polarity, and phase angle tests
• Automatically demagnetize CT under test when performing excitation tests
• Measure the DC resistance of transformer windings from 100 micro-ohms to 20 ohms
• Stand-alone or computer-controlled via USB or optional Bluetooth wireless interface
In addition to the above, the EZCT-2000C Plus offers the following features:
• Measures the insulation resistance of the CT's secondary winding
• Measures the CT’s load burden
• Provides a programmable current source (0-20A) that can be used to verify CT loads
The EZCT-2000C’s test leads can be connected to all the CT output terminals, and the complete
CT test can be performed automatically without any operator intervention.
1.2 Common Features (EZCT-2000C and EZCT-2000C Plus)
Excitation Test
The CT excitation test is performed using the ANSI/IEEE C57.13.1 test method. Test voltage
ranges from 50, 300, 500,1200 and 2000 Vac can be selected for the excitation test. The test
voltage is raised and lowered automatically by the EZCT-2000C. The excitation test voltage and
current data is collected and stored in the EZCT-2000C’s internal memory. Knee point voltages
(ANSI 10/50, IEC 60044, IEEE-30, IEEE-45) are calculated and printed on the test report. All of
the EZCT-2000C’s test leads can be connected to the CT output terminals (X1, X2, X3, X4 and
X5), and there is no lead switching required during testing. This convenient arrangement allows
for testing any of the 10 possible combinations of X1 to X5. Up to 10 excitation tests can be
stored in one record. Once the test is completed, the test report and CT excitation curves can
be printed on the built-in thermal printer.
Demagnetization
The EZCT-2000C automatically demagnetizes the CT under test when performing an excitation
test.
Winding Resistance Test
The EZCT-2000C can measure the DC resistance of transformer windings from 100 micro-ohms
to 10 ohms.
Ratio and Polarity Tests
The CT current-ratio is determined using the ANSI/IEEE C57.12.90 measurement method. A test
voltage is applied on any two terminals (X1 to X5) of the CT, and the induced voltage is
measured through the H1 and H2 terminals of the CT. The CT current-ratio is displayed and also
stored in memory. The current-ratio is measured from 0.8 to 5,000. The CT winding polarity is