Vanguard Instruments EZCT User manual

EZCT and EZCT-10
DIGITAL CURRENT-TRANSFORMER TESTERS
USER’S MANUAL
Vanguard Instruments Company, Inc.
1520 S. Hellman Ave.
Ontario, California 91761, USA
TEL: [phone]
FAX: [phone]
February 2010
Revision 4
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EZCT/EZCT-10 USER’S MANUAL REV 4
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SAFETY SUMMARY
This manual applies to the EZCT and EZCT-10 Current Transformer Testers. The operating
procedures are virtually the same for both models, and any differences in operation are clearly
described in the step-by-step procedures.
FOLLOW EXACT OPERATING PROCEDURES
Any deviation from the procedures described in this User’s Manual may create one or more
safety hazards, may damage the EZCT/EZCT-10, or cause errors in the test results. Vanguard
Instruments Company, Inc. assumes no liability for unsafe or improper use of the EZCT/EZCT-10.
All safety precautions provided in this manual must be observed during all phases of testing
including test preparation, test lead connection, actual testing, and test lead disconnection.
SAFETY WARNINGS AND CAUTIONS
The EZCT/EZCT-10 can produce a voltage up to 1,200 Vac that can cause severe injury and/or
equipment damage. Due to this reason, the EZCT/EZCT-10 shall be used only by trained
operators.
The EZCT/EZCT-10’s X output terminals are rated to 1,200 Vac working voltage. Any voltage
above 1,200 Vac will damage the input circuitry.
All devices under test shall be off-line and fully isolated. Never attempt to test any current
transformer still connected to a circuit. All current transformer terminals shall be isolated
before conducting any test with the EZCT/EZCT-10.
Always ground the EZCT/EZCT-10 to a substation ground before connecting the test cables to a
transformer.
DO NOT MODIFY TEST EQUIPMENT
To avoid the risk of introducing additional or unknown hazards, do not install substitute parts or
perform any unauthorized modification to any EZCT/EZCT-10 test unit. To ensure that all
designed safety features are maintained, it is highly recommended that repairs be performed
only by Vanguard Instruments Company factory personnel or by an authorized repair service
provider. Unauthorized modifications can cause safety hazards and will void the manufacturer’s
warranty.
WARNING
Do not remove test leads during a test. Failure to heed this warning can result in electrical
shock to personnel and damage to the equipment.
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TABLE OF CONTENTS
CONVENTIONS USED IN THIS DOCUMENT ..................................................................................... 1
1.0 INTRODUCTION.................................................................................................................... 2
1.1 General Description and Features ................................................................................... 2
1.2 Furnished Accessories...................................................................................................... 3
1.3 Technical Specifications ................................................................................................... 4
1.3.1. EZCT Technical Specifications................................................................................... 4
1.3.2. EZCT-10 Technical Specifications ............................................................................. 5
1.4 Controls and Indicators.................................................................................................... 6
2.0 PRE-TEST SETUP ................................................................................................................... 8
2.1 Operating Voltages .......................................................................................................... 8
2.2 LCD Screen Contrast Control............................................................................................ 8
2.3 Printer Paper Control....................................................................................................... 8
2.4 Printer Paper.................................................................................................................... 8
3.0 OPERATING PROCEDURES ................................................................................................. 10
3.1 EZCT Cable Connections................................................................................................. 10
3.2 Performing Tests............................................................................................................ 13
3.2.1. Entering Test Record Header Information ............................................................. 13
3.2.2. Performing an Excitation and Ratio Test................................................................ 16
3.2.3. Performing a Turns Ratio Only Test ....................................................................... 23
3.3 Working With Test Records ........................................................................................... 27
3.3.1. Printing a Test Record Directory ............................................................................ 27
3.3.2. Restoring and Printing a Test Record From Flash EEPROM ................................... 29
3.3.3. Printing a Restored Test Record............................................................................. 32
3.3.4. Erasing Test Records From the Flash EEPROM ...................................................... 33
4.0 CHANGING SETUP PARAMETERS ....................................................................................... 35
4.1 Setting the Knee Point Marker ...................................................................................... 35
4.2 Selecting the Buried CT in Transformer Delta Option ................................................... 37
4.2.1. Enabling the Buried CT in Transformer Delta Option............................................. 37
4.2.2. Disabling the Buried CT in Transformer Delta Option............................................ 38
4.3 Setting the Clock ............................................................................................................ 42
4.4 Setting the Option to Print Impedance (Z) in the Tabulated Results ............................ 43
5.0 DIAGNOSTICS, VERIFICATION, AND TROUBLESHOOTING ................................................. 46
5.1 Performing a Diagnostics Test ....................................................................................... 46
5.2 Verifying the EZCT’s VxSense Circuit Using an External Meter ..................................... 48
5.3 Verifying the EZCT’s IxSense Circuit Using an External Meter ...................................... 49
5.4 Quickly Verifying the EZCT’s Turns Ratio Circuit............................................................ 50
5.5 Troubleshooting Guide .................................................................................................. 51
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LIST OF TABLES
Table 1. EZCT Technical Specifications ........................................................................................... 4
Table 2. EZCT-10 Technical Specifications ...................................................................................... 5
Table 3. Functional Descriptions of EZCT/EZCT-10 Controls and Indicators .................................. 7
Table 4. Descriptions of Tabulated Test Results Elements ........................................................... 22
LIST OF FIGURES
Figure 1. EZCT/EZCT-10 Controls and Indicators ............................................................................ 6
Figure 2. Typical EZCT Cable Connection ...................................................................................... 10
Figure 3. Connection to CT’s on Y Transformer ............................................................................ 11
Figure 4. Connection to CT's on a Delta Transformer................................................................... 11
Figure 5. Typical EZCT Connection to Multiple CT’s ..................................................................... 12
Figure 6. Typical EZCT Tabulated Report Printout ........................................................................ 21
Figure 7. Typical EZCT Excitation Graph........................................................................................ 22
Figure 8. Typical Turns Ratio Only Test Report Printout .............................................................. 26
Figure 9. Sample Test Record Directory Printout ......................................................................... 28
Figure 10. Typical Abbreviated Test Record Printout ................................................................... 31
Figure 11. Graphic Report Showing Knee Point Marker............................................................... 36
Figure 12. Buried CT in a Delta Transformer Illustration 1 ........................................................... 40
Figure 13. Buried CT in a Delta Transformer Illustration 2 ........................................................... 40
Figure 14. Tabulated Report Printout with Impedance Values .................................................... 45
Figure 15. EZCT VxVerification Test Connections......................................................................... 48
Figure 16. EZCT IxVerification Test Connections .......................................................................... 49
Figure 17. EZCT Turns Ratio Verification Test Connections.......................................................... 50
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CONVENTIONS USED IN THIS DOCUMENT
This document uses the following conventions:
•A key, switch, or knob on the EZCT/EZCT-10 is indicated as [KEY], [SWITCH], [KNOB].
•Menu options are referenced as (MENU OPTION).
•Both the EZCT and the EZCT-10 are simply referred to as “EZCT” in this manual. The exact
model number is used only in cases where differences between the units are discussed.
•Screen and menu names are referenced as “SCREEN/MENU NAME”.
•The terms “test record” and “test shot” are used interchangeably.
•EZCT/EZCT-10 LCD screen output is shown as:
•Warning messages are indicated as:
WARNING
Warning message
•Important notes are indicated as:
NOTE
Note details
1. OPTION 1
2. OPTION 2
3. OPTION 3
4. OPTION 4
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1.0 INTRODUCTION
1.1 General Description and Features
The EZCT is a microprocessor-based, current-transformer test set. This rugged and portable test
set can perform the current transformer (CT) excitation, CT current-ratio, and winding polarity
tests. Current transformers can be tested in their field-mounted configuration, eliminating the
need to remove bushings or current transformers from the host equipment. The EZCT is
capable of outputting 50 Vac at 2A and 200 Vac at 2A.
The EZCT-10 has all the features of the EZCT, but uses a heavy-duty transformer to perform the
CT excitation test. It is capable of outputting 50 Vac at 10A and 200 Vac at 10A.
CT Excitation Test
The CT excitation test is performed using the ANSI/IEEE C57.13.1, IEC 60044-1 test method. The
EZCT applies an AC variable test voltage (up to 1,200 Vac) to the CT’s secondary windings. The
EZCT records and displays the test voltage and excitation current applied to the current
transformer during the excitation test. Once tests are completed, up to 10 excitation curves and
knee-point voltages of the tests can be plotted on the built-in thermal printer. IEEE-30, IEEE-45,
ANSI/IEC 60044-1 (10/50) knee point voltages are also calculated and printed on the test
report.
CT Ratio and Polarity Tests
The EZCT determines the CT current-ratio using the ANSI/IEEE C57.12.90 measurement
method. A test voltage is applied on the CT’s X terminals and the induced voltage is measured
across the CT’s H1 and H2 terminals. The current-ratio is displayed on the screen and stored in
memory. The current-ratio measuring range is from 0.8 to 5,000. Winding polarity is displayed
as a “+” sign (in-phase) or “-” sign (out-of-phase) and is annotated with the phase angle in
degrees.
User Interface
The EZCT features a back-lit LCD screen (4 lines by 20 characters) that is viewable in both bright
sunlight and low-light levels. A rugged, alpha-numeric, membrane keypad is used to enter test
information and to control the unit’s functions. The test voltage range (50V at 2A, 200V at 2A,
1,200V at 1.5A) is selected with a switch on the control panel. A voltage control knob is used to
control the variable test voltage output.
Thermal Printer
A built-in 4.5-inch wide thermal printer can print the current transformer test report and plot
the excitation curves..
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Computer Interface
The EZCT can be used as a stand-alone unit or can be computer-controlled via the built-in RS-
232C or USB interfaces. Windows® XP/Vista-based Current Transformer Analysis software is
provided with each EZCT. This software can be used to retrieve test records from the EZCT and
can also be used to run CT tests from the PC. Tabulated test records can be exported in
Microsoft® Excel format.
1.2 Furnished Accessories
The EZCT comes furnished with the following:
•One Power Cord
•One Ground Cable
•One 20-foot X Cable Set
•One 35-foot H Cable Set
•One cable carrying duffel bag
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1.3 Technical Specifications
1.3.1. EZCT Technical Specifications
Table 1. EZCT Technical Specifications
TYPE Portable current-transformer test set
PHYSICAL SPECIFICATIONS 16.8”W x 12.6”H x 12”D (42.7 cm x 32 cm x 26.9 cm); Weight: 55 lbs (25 Kg)
INPUT POWER 100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
MEASUREMENT METHOD ANSI/IEEE C57.12.90, IEC 60044-1 and ANSI/IEEE C57.13.1
OUTPUT
TEST OUTPUT VOLTAGES 0 – 50 Vac @ 2A max; 0 – 200 Vac @ 2A max; 0 – 1200 Vac @ 1.5A max (5 min on, 10 min off)
VOLTAGE READING RANGE 0 – 1,250 Vac; Accuracy: ±1.0% of reading, ±0.5 volt
CURRENT READING RANGE 0 – 10A; Accuracy: ±1.0% of reading, ±0.01A
CURRENT-RATIO RANGE 0.8 – 99: ±0.5%, 100 – 999: ±1.0%, 1,000 – 5,000: ±2%
PHASE ANGLE
MEASUREMENT 0 – 360 degrees; Accuracy: ±1.0 degree
DISPLAY Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight
and low-light levels
PRINTER Built-in 4.5-inch wide thermal printer
COMPUTER INTERFACES One RS-232C port, One USB port
PC SOFTWARE Windows
®
XP/Vista-based software is included with purchase price
INTERNAL
TEST RECORD STORAGE Stores 128 test records. Each test record may contain up to 10 excitation and ratio data sets
INTERNAL
TEST HEADER STORAGE Stores 10 test header records
SAFETY Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92
standards
ENVIRONMENT Operating: -10˚to 50˚C (15˚F to +122˚F); Storage: -30˚C to 70˚C (-22˚F to
+158˚F)
CABLES One 20-foot X cable set, One 35-foot H cable set, power cord, One ground
cable, One cable carrying duffel bag
OPTIONS Transportation case
WARRANTY One year on parts and labor
NOTE
The above specifications are valid at nominal operating voltage and at a
temperature of 25°C (77°F). Specifications may change without prior notice.
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1.3.2. EZCT-10 Technical Specifications
Table 2. EZCT-10 Technical Specifications
TYPE Portable current-transformer test set
PHYSICAL SPECIFICATIONS 16.8”W x 12.6”H x 12”D (42.7 cm x 32 cm x 26.9 cm); Weight: 55 lbs (25 Kg)
INPUT POWER 100 – 120 Vac or 200 - 240 Vac (factory pre-set), 50/60 Hz
MEASUREMENT METHOD ANSI/IEEE C57.12.90, IEC 60044-1 and ANSI/IEEE C57.13.1
OUTPUT
TEST OUTPUT VOLTAGES 0 – 50 Vac @ 10A max; 0 – 200 Vac @ 10A max; 0 – 1200 Vac @ 1.5A max (5 min on, 10 min off)
VOLTAGE READING RANGE 0 – 1,250 Vac; Accuracy: ±1.0% of reading, ±0.5 volt
CURRENT READING RANGE 0 – 10A; Accuracy: ±1.0% of reading, ±0.02A
CURRENT-RATIO RANGE 0.8 – 99: ±0.5%, 100 – 999: ±1.0%, 1,000 – 5,000: ±2%
PHASE ANGLE
MEASUREMENT 0 – 360 degrees; Accuracy: ±1.0 degree
DISPLAY Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight
and low-light levels
PRINTER Built-in 4.5-inch wide thermal printer
COMPUTER INTERFACES One RS-232C port, One USB port
PC SOFTWARE Windows
®
XP/Vista-based software is included with purchase price
INTERNAL
TEST RECORD STORAGE Stores 128 test records. Each test record may contain up to 10 excitation and ratio data sets
INTERNAL
TEST HEADER STORAGE Stores 10 test header records
SAFETY Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92
standards
ENVIRONMENT Operating: -10˚to 50˚C (15˚F to +122˚F); Storage: -30˚C to 70˚C (-22˚F to
+158˚F)
CABLES One 20-foot X cable set, One 35-foot H cable set, power cord, One ground
cable, One cable carrying duffel bag
OPTIONS Transportation case
WARRANTY One year on parts and labor
NOTE
The above specifications are valid at nominal operating voltage and at a
temperature of 25°C (77°F). Specifications may change without prior notice.
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1.4 Controls and Indicators
The EZCT and EZCT-10 feature the same controls and indicators shown in Figure 1. A leader line
with an index number points to each control and indicator, which is cross-referenced to a
functional description in Table 3. The table describes the function of each item on the control
panel. The purpose of the controls and indicators may seem obvious, but users should become
familiar with them before using the EZCT. Accidental misuse of the controls will usually cause
no serious harm. Users should also be familiar with the safety summary found on the front page
of this User’s Manual.
Figure 1. EZCT/EZCT-10 Controls and Indicators
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