Vanguard Instruments EZCT S2 User manual

EZCT S2TM
DIGITAL CURRENT-TRANSFORMER TESTER
USER’S MANUAL
Vanguard Instruments Company, Inc.
1520 S. Hellman Ave.
Ontario, California 91761, USA
TEL: [phone]
FAX: [phone]
December 2009
Revision 3

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SAFETY SUMMARY
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 S2, or cause errors in the test results. Vanguard
Instruments Company, Inc. assumes no liability for unsafe or improper use of the EZCT S2.
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 S2 can produce a voltage up to 1,500 Vac that can cause severe injury and/or
equipment damage. Due to this reason, the EZCT S2 shall be used only by trained operators.
The EZCT S2’s X output terminals are rated to 1,500 Vac working voltage. Any voltage above
1,500 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 S2.
Always ground the EZCT S2 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 S2 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
1.4 EZCT S2 Controls and Indicators ...................................................................................... 5
2.0 PRE-TEST SETUP ................................................................................................................... 7
2.1 Operating Voltages .......................................................................................................... 7
2.2 LCD Screen Contrast Control............................................................................................ 7
2.3 Printer Paper Control....................................................................................................... 7
2.4 Printer Paper.................................................................................................................... 7
3.0 OPERATING PROCEDURES ................................................................................................... 9
3.1 EZCT S2 Cable Connections.............................................................................................. 9
3.2 Performing Tests............................................................................................................ 11
3.2.1. Entering Test Record Header Information ............................................................. 11
3.2.2. Performing Excitation and Ratio Tests ................................................................... 14
3.3 Working With Test Records ........................................................................................... 22
3.3.1. Restoring and Printing a Test Record From Flash EEPROM ................................... 22
3.3.2. Printing a Restored Test Record............................................................................. 25
3.3.3. Printing a Directory of Test Records Stored in the EZCT S2’s Memory.................. 26
3.3.4. Erasing Test Records From the Flash EEPROM ...................................................... 28
3.4 Working With Test Plans................................................................................................ 30
3.4.1. Extracting the Test Plan From a Test Record ......................................................... 30
3.4.2. Printing a Directory of Test Plans Stored in the EZCT S2’s Memory ...................... 32
3.4.3. Printing a Test Plan................................................................................................. 34
3.4.4. Erasing Test Plans From the Flash EEPROM........................................................... 36
3.4.5. Loading a Test Plan from the EZCT S2’s Flash EEPROM ......................................... 38
3.4.6. Running a Test Using a Loaded Test Plan............................................................... 39
3.4.7. Unloading a Test Plan from the Working Memory ................................................ 43
4.0 CHANGING SETUP PARAMETERS ....................................................................................... 44
4.1 Setting the Knee Point Marker ...................................................................................... 44
4.2 Selecting the Buried CT in Transformer Delta Option ................................................... 46
4.3 Setting the Clock ............................................................................................................ 49
5.0 DIAGNOSTICS, VERIFICATION, AND TROUBLESHOOTING ................................................. 50
5.1 Performing a Diagnostics Test ....................................................................................... 50
5.2 Verifying the EZCT S2’s VxSense Circuit Using an External Meter ................................ 51
5.3 Verifying the EZCT S2’s IxSense Circuit Using an External Meter.................................. 52
5.4 Quickly Verifying the EZCT S2’s Turns Ratio Circuit....................................................... 53
5.5 Troubleshooting Guide .................................................................................................. 54

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LIST OF TABLES
Table 1. EZCT S2 Technical Specifications....................................................................................... 4
Table 2. Functional Descriptions of EZCT S2 Controls and Indicators ............................................ 6
Table 3. Descriptions of Tabulated Test Results Elements ........................................................... 20
Table 4. Description of Test Plan Elements .................................................................................. 35
LIST OF FIGURES
Figure 1. EZCT S2 Controls and Indicators ...................................................................................... 5
Figure 2. Typical EZCT S2 Excitation and Ratio Test Cable Connection .......................................... 9
Figure 3. Bushing CT Connection on Delta Transformer .............................................................. 10
Figure 4. Bushing CT Connection on Y Transformer ..................................................................... 10
Figure 5. Typical EZCT S2 Tabulated Report Printout ................................................................... 19
Figure 6. Typical EZCT S2 Graphic Report ..................................................................................... 21
Figure 7. Typical Internal Test Record Directory Printout ............................................................ 27
Figure 8. Typical EZCT S2 Flash EEPROM Test Plan Directory Printout ........................................ 33
Figure 9. Typical Test Plan Printout .............................................................................................. 35
Figure 10. Graphic Report Showing Knee Point Marker............................................................... 45
Figure 11. Buried CT in a Delta Transformer Illustration 1 ........................................................... 47
Figure 12. Buried CT in a Delta Transformer Illustration 2 ........................................................... 47
Figure 13. EZCT S2 VxVerification Test Connections .................................................................... 51
Figure 14. EZCT S2 IxVerification Test Connections ..................................................................... 52
Figure 15. EZCT S2 Turns Ratio Verification Test Connections ..................................................... 53

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CONVENTIONS USED IN THIS DOCUMENT
This document uses the following conventions:
•A key or switch on the EZCT S2 is indicated as [KEY] and [SWITCH].
•Menu options are referenced as (MENU OPTION).
•Screen and menu names are referenced as “SCREEN/MENU NAME”.
•The terms “test record” and “test shot” are used interchangeably.
•EZCT S2 LCD screen output is shown as:
•When instructions are provided, the menu item that should be selected is shown in bold as
shown below (option 3 should be selected):
•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
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 S2 is Vanguard’s second-generation, microprocessor-based, current transformer test
set. The EZCT S2 can perform the current transformer (CT) excitation, CT current-ratio, and
winding polarity tests automatically. The EZCT S2 automatically raises and lowers the excitation
test voltage without any operator intervention. With up to 1500 Vac excitation test voltage
available, the EZCT S2 can easily perform excitation tests on very large CT’s.
Excitation Test
The CT excitation test is performed using the ANSI/IEEE C57.13.1, IEC 60044-1 test method. The
test voltage range for the CT excitation test (50 Vac, 250 Vac, 500 Vac, or 1500 Vac) can be
selected, and then the test voltage is raised and lowered automatically by the EZCT S2. The test
voltage and current data are collected and stored in the unit’s internal memory. Up to 10 CT
excitation and current-ratio tests can be stored in one test record. IEEE-30, IEEE-45, ANSI/IEC
60044-1 (10/50) knee point voltages are also calculated and printed on the test report. Once
the test is completed, test results can be printed and excitation curves can be plotted on the
built-in 4.5-inch wide thermal printer.
CT Ratio and Polarity Test
The EZCT S2 determines the CT current-ratio using the ANSI/IEEE C57.12.90 measurement
method. A test voltage is applied to the CT’s secondary terminals and the induced voltage is
measured through the CT’s H1 and H2 terminals. The CT current-ratio and polarity are displayed
on the screen and stored in memory. The current-ratio measuring range is from 0.8 to 5,000.
The CT winding polarity is displayed as a “+” sign (in-phase) or a “-” sign (out-of-phase) and is
annotated with the phase angle in degrees.
User Interface and Display
The EZCT S2 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
control the unit.
Built-in 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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Test Record Header Information
The test record header information can include the company name, substation name, circuit ID,
manufacturer, CT serial number, operator’s name, and test record comments. In addition to the
test record header, a 20-character test description for each test in the record can also be
entered.
Internal Test Record Storage Capacity
The EZCT S2 can store up to 140 test records in Flash EEPROM. Each test record may contain up
to 10 excitation curves, current-ratio readings, and winding polarity readings. Test records can
be recalled and printed on the built-in thermal printer.
Internal Test Plan Storage Capacity
The EZCT S2 can store up to 128 CT test plans in Flash EEPROM. A test plan defines the
excitation test voltage and current selection, CT nameplate ratio, and CT winding terminal
connection instructions for each test. Up to 10 test definitions can be stored in each test plan.
The use of a test plan greatly simplifies the CT testing process since it also provides instructions
for making the proper CT cable connections. Test plans can be created on the EZCT S2 itself or
created on a PC and downloaded to the EZCT S2 via the unit’s built-in RS-232C or USB port.
Computer Interface
The EZCT S2 can be used as a stand-alone unit or can be computer-controlled via the built-in RS-
232C or USB interfaces. A Windows® XP/Vista-based Current Transformer Analysis software
application is provided with each EZCT S2. This software can be used to retrieve test records
from the EZCT S2, create test plans, download test plans to the EZCT S2, 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 S2 comes furnished with the following:
•1 Power Cord
•2 20-foot X Cable Sets
•1 35-foot H Cable Set
•One RS-232C serial cable
•One USB cable
•Ground Cables
•Cable carrying duffel bag

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1.3 Technical Specifications
Table 1. EZCT S2 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 Hz/60 Hz
MEASUREMENT METHOD ANSI/IEEE C57.12.90, IEC 60044-1 and ANSI/IEEE C57.13.1 standards
TEST OUTPUT VOLTAGES 0 – 50 Vac @ 10A max, 0 – 250 Vac @ 10A max
0 – 500 Vac @ 5A max, 0 – 1500 Vac @ 1.2A max
VOLTAGE READING RANGE 0 – 2,200 Vac; Accuracy: ±1.0% of reading, ±1 volt
CURRENT READING RANGE 0 – 10A; Accuracy: ±1.0% of reading, ±0.02A
CURRENT-RATIO RANGE 0.8 – 999: 0.1%, 1000 – 1999: 0.3%, 2000 – 5000: 1%
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 (115k baud), one USB port
PC SOFTWARE Windows
®
XP/Vista-based CT Analysis software is included with purchase
price
INTERNAL TEST RECORD
STORAGE Stores 140 test records. Each test record may contain up to 10 sets of excitation, resistance and ratio data
INTERNAL TEST PLAN
STORAGE Stores 128 test plans. Each test plan can store 10 excitation test voltage and current settings
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 Two 20-foot X cable sets, One 35-foot H cable set, power cord, One cable-
carrying duffel bag
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 EZCT S2 Controls and Indicators
The EZCT S2’s controls and indicators are shown in Figure 1 below. A leader line with an index
number points to each control and indicator, which is cross-referenced to a functional
description in Table 2. 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 S2. 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 S2 Controls and Indicators

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Table 2. Functional Descriptions of EZCT S2 Controls and Indicators
Item
Number Panel Markings Functional Description
1 X Current transformer excitation voltage connector. The EZCT S2’s X output terminal is rated to 1500 Vac working voltage. Any voltage above 1500 Vac
will damage the input circuitry.
2 H Current transformer primary input test cable connector.
3 Built-in 4.5-inch wide thermal printer.
4 110-120 Vac,
12A, 50-60Hz Power switch with built-in circuit breaker.
5 Power receptacle.
6 GROUND Ground terminal.
7 Back-lit LCD screen (20 characters by 4 lines); viewable in bright sunlight and
low-light levels.
8 USB USB PC interface
9 RS-232C RS-232C PC interface. Baud rate is set for 115KB, 8 data bits, 2 stop bits.
10 Rugged alpha-numeric keypad.
11 EMERGENCY
TURN OFF
“PUSH”
Emergency turn off switch.
12 HIGH VOLTAGE
PRESENT Test voltage presence indicator.