Megger TTR320 Series User manual

AVTMTTR320-EN
Rev A
October 2008
Instruction Manual
for
Three-Phase TTR®
Transformer Turn Ratio Test Set
TTR320 series
Catalog Numbers. TTR320, TTR320-47
HIGH-VOLTAGE EQUIPMENT
Read this entire manual before operating.
M
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403-2329
U.S.A.
610-676-8500
www.megger.com

Three-Phase TTR®
Transformer Turn Ratio Test Set
TTR320 series

Copyright© 2008 by Megger. All rights reserved.
The information presented in this manual is believed to be adequate for the intended use of the product.
If the product or its individual instruments are used for purposes other than those specified herein,
confirmation of their validity and suitability must be obtained from Megger. Refer to the warranty
information below. Specifications are subject to change without notice.
WARRANTY
Products supplied by Megger are warranted against defects in material and workmanship for a period of
one year following shipment. Our liability is specifically limited to replacing or repairing, at our option,
defective equipment. Equipment returned to the factory for repair must be shipped prepaid and insured.
Contact your MEGGER representative for instructions and a return authorization (RA) number. Please
indicate all pertinent information, including problem symptoms. Also specify the serial number and the
catalog number of the unit. This warranty does not include batteries, lamps or other expendable items,
where the original manufacturer’s warranty shall apply. We make no other warranty. The warranty is
void in the event of abuse (failure to follow recommended operating procedures) or failure by the
customer to perform specific maintenance as indicated in this manual.
M
Valley Forge Corporate Center
2621 Van Buren Ave
Norristown, PA 19403-2329
610-676-8500 (Telephone)
610-676-8610 (Fax)
www.megger.com

AVTMTTR320-EN Rev A Oct 2008
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Table of Contents
1. Getting to know the TTR320............................................................................................................................1
Product Overview ................................................................................................................................................1
User Interface Panel.............................................................................................................................................4
Communications ports ........................................................................................................................................5
HOME Action Icons...........................................................................................................................................5
Utility Icons...........................................................................................................................................................6
2. Safety .....................................................................................................................................................................7
Safety is the responsibility of the user...............................................................................................................7
Input Power precautions.....................................................................................................................................8
3. PREPARING FOR TEST ................................................................................................................................9
Site Preparation.....................................................................................................................................................9
Making Circuit Connections...............................................................................................................................9
4. Connecting to the Transformer...................................................................................................................... 11
Single-Phase, Two-Winding Transformers.................................................................................................... 11
Three-Phase, Two-Winding Transformers.................................................................................................... 14
Three-Phase, Three-Winding Transformers ................................................................................................. 15
Current Transformers (CTs)............................................................................................................................ 16
BCTs Mounted on Three-Phase Transformers ............................................................................................ 19
T-Type Transformers ....................................................................................................................................... 22
5. Operation........................................................................................................................................................... 23
Power up............................................................................................................................................................. 23
Navigating the screen........................................................................................................................................ 23
HOME Screen Action Icons........................................................................................................................... 23
Remote Control Operation for LTC Testing................................................................................................ 28
Error Messages .................................................................................................................................................. 28
Upon completion of TEST – Powering down ............................................................................................. 29
6. Service ................................................................................................................................................................ 31
Maintenance ....................................................................................................................................................... 31
Fuse Replacement ............................................................................................................................................. 31
Calibration .......................................................................................................................................................... 32
TTR320 – Self check ........................................................................................................................................ 32
Troubleshooting ................................................................................................................................................ 34
Repairs................................................................................................................................................................. 35
7. Replacement Parts List and Optional Accessories ...................................................................................... 37
8. Specifications..................................................................................................................................................... 39
Electrical ............................................................................................................................................................. 39
Environmental Conditions............................................................................................................................... 41
Physical Data...................................................................................................................................................... 41
Addendum A TTR 300 Series PowerDB Lite User Manual ........................................................................... 43

AVTMTTR320-EN Rev A Oct 2008
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List of Figures
TTR320 Transformer Turn Ratio test set............................................................................................................iii
Figure 1-1. Top Panel Controls..............................................................................................................................3
Figure 1-2. User Interface Panel............................................................................................................................4
Figure 1-3. Communications ports .......................................................................................................................5
Figure 1-4. HOME Action Icons..........................................................................................................................5
Figure 1-5. Utility Icons..........................................................................................................................................6
Figure 4-1. Setup for Testing Single-Phase Transformer................................................................................12
Figure 4-2. Setup for Testing Single-Phase Autotransformer........................................................................12
Figure 4-3. Setup for Testing Single-Phase, Type A (Straight Design) Step Voltage Regulator ...............13
Figure 4-4. Setup for Testing Single-Phase, Type B (Inverted Design) Step Voltage Regulator..............14
Figure 4-5. Setup for Testing Unmounted Current Transformer .................................................................17
Figure 4-6. Setup for Testing Taps on Multiple Tap CT................................................................................18
Figure 4-7. Setup for Testing BCT Mounted on Single-Phase Two-Winding Transformer.....................19
Figure 4-8. Setup for Testing BCT Mounted on Delta Winding -Three-Phase Power Transformer ......20
Figure 4-9. Setup for Testing BCT Mounted on Wye Winding of a Three-Phase Transformer..............21
Figure 5-1 Cleared Test screen..........................................................................................................................24
Figure 5-2 File Manager -Recall Test................................................................................................................25
Figure 5-3. File Manager –SAVE Test screen..................................................................................................26
Figure 5-4 Tap Structure - Define ....................................................................................................................26
Figure 5-5 Global Settings – Preferences screen ............................................................................................27
List of Tables
Table 4-1. Test Lead Markings for Single-Phase Transformers...................................................................13
Table 4-2. Test Lead Markings for Three-Phase Transformers...................................................................15
Table 4-3. T-type Transformer Winding Phase Relationship.......................................................................22
Table 6-1. Troubleshooting Guide...................................................................................................................34
Table 7-1. Replacement Parts List....................................................................................................................37

AVTMTTR320-EN Rev A Oct 2008
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Upon Receipt of Product
Prior to operation, check for loosened hardware or damage incurred during
transit. If these conditions are found, a safety hazard is likely, DO NOT attempt
to operate equipment. Please contact Megger as soon as possible.
TTR320 Transformer Turn Ratio test set

AVTMTTR320-EN Rev A Oct 2008
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1
Getting to know the TTR320
Product Overview
The Three-Phase TTR® Test Set is fully automatic, self-checking, menu-driven
unit. The test set measures the turn ratio, phase shift, and excitation current of
power, distribution, and instrument transformers. A “-47” suffix added to the
catalog number denotes a 230-V input power supply, rather than the standard
120-V supply. The test set is a portable instrument housed in a sturdy plastic case
with removable lid and carrying strap. The inside lining of case is metal shielded.
A canvas carrying bag is supplied to hold all accessories.
The test set can be used to test single-phase and three-phase transformers, both
with and without taps in accordance with the requirements of the IEEE
C57.12.90 – 1997 standards. For three-phase measurements, the test set is
connected to all three phases of the transformer to be tested. The TTR lead
selection circuitry permits automatic measurement of all phases without changing
connections. This feature eliminates the need to refer to hook-up charts when
testing three-phase transformers. Turn ratio, phase shift and excitation current
readings are displayed on a large LCD. Transformer excitation current as well as
phase shift angle helps to detect transformer shorted turns or an unequal number
of turns connected in parallel. Operating condition (error) messages identify
incorrect test connections, abnormal operating condition, or winding problems.
Test results can be saved either to internal memory, to an external USB storage
device, or can be uploaded to a personal computer (PC) via an ethernet port.
Features include:
Fully automatic operation.
Self-checking at power-up.
User-friendly, menu-driven operation.
Test turn ratio, phase shift (in both degree and centiradian), and excitation
current.
Easy measuring of regular windings, tertiary windings, and CTs.
Storage capacity to handle over 1000 test files (depending on size).

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Checking reverse polarity at start of each test.
Via ethernet port, an external PC or laptop can be connected to operate the
TTR (in remote control mode) or to transfer test results and to provide full
transformer test report.
Quick test mode provides the fastest testing of a transformer.
Three excitation test voltages: 80 V, 40 V, and 8 V.
Testing to ANSI, IEC, and Australian standards.
Leads marked to ANSI, IEC, and Australian standards.
Multi-lingual support.
Large, easy-to-read, full VGA color display
Meets the requirements of both the European EMC and Low Voltage
Directives.
It is recommended that the user becomes familiar with the TTR320 before ever
connecting to a transformer.

Getting to Know the TTR320
AVTMTTR320-EN Rev A Oct 2008
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Top Panel Controls
Figure 1-1. Top Panel Controls
1. Power input receptacle, ON/OFF switch, and fuse holder. ON/OFF power
switch and input power receptacle provides power to the test set.
2. Emergency OFF switch. This red push button interrupts testing. When
pressed, the switch is locked in off position. To reset the switch, twist the
button in the direction indicated by the arrows.
3. Voltage ON light. Red indicator lamp indicates when lit that test voltage is
being supplied to the Unit Under Test (UUT).
4. Remote Trigger receptacle. Plug receptacle for connecting Remote Trigger
cable for testing transformers with Load-Tap-Changers.
5. H – Cable receptacle. Plug receptacle for connecting test leads to the high-
voltage (H) winding of a transformer
6. X – Cable receptacle. Plug receptacle for connecting test leads to the low-
voltage (X) winding of a transformer.
7. Ground lug. Wing-nut terminal allows connection of test set to Station
Earth ground.

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User Interface Panel
Test Button:
Initiates and Terminates Testing
Navigation Keys:
Use Arrow keys to highlight a desired Selection. Use
Enter button (in center) to Activate the Selection.
Home Key:
Toggles HOME Action Icons
Zone Key:
Allows User to select Active area of the screen.
Keypad: Key board for entering notes and data.
Power Suspend:
Prepares the Instrument for Shutdown. A message will
indicate when Input Power can be safely removed (not
used on some models)
Help Function:
Provides on screen Help to assist operator.
Information Key:
Provides on screen information to assist operator
Function Key:
Displays the options available for any highlighted
Selection (when applicable)
Figure 1-2. User Interface Panel

Getting to Know the TTR320
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Communications ports
Ethernet port
Serial port (PRINT) / USB Storage
Figure 1-3. Communications ports
HOME Action Icons
Select to create NEW test
Select to define Transformer Tap Structure
Select to RECALL test
Select to SAVE Test.
Print Icon. Prints the Selected Test data. Printer driver is factory installed. Please
contact Megger for specific printer model availability.
Select to enter PREFERENCES screen
Figure 1-4. HOME Action Icons

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Utility Icons
Delete Icon. Deletes the Selected File or Report.
Print Icon. Prints the Selected Report. Printer must be standard USB
supporting HP PCL protocol.
USB Out Icon. Select to Transfer Files or Reports from external USB
Memory Stick to the TTR.
USB In Icon. Select to Transfer Files or Reports from the TTR to the
external USB Memory Stick.
Back Icon. Select to return back to the previous screen.
Figure 1-5. Utility Icons

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2
Safety
Safety is the responsibility of the user
Only qualified and trained operators should operate the TTR320 system.
Operator must read and understand this entire Instruction Manual prior to
operating the equipment. Operator must follow the instructions of this
Instruction Manual and attend the equipment while the equipment is in use. In
the event of equipment malfunction, the unit should immediately be de-
energized and returned to Megger for repair. The Safety precautions herein are
not intended to replace your Company’s Safety Procedures. Refer to IEEE 510 -
1983, IEEE Recommended Practices for Safety in High-Voltage and High-
Power Testing, for additional information.
General Safety Precautions
The TTR320 and the Unit Under Test (UUT) should both be considered as
sources of instantaneously lethal levels of electrical energy. Observe the
following safety precautions:
Observe all safety warnings on the equipment. They identify areas of
immediate hazard that could result in injury or death.
Use this equipment only for the purposes described in this manual. Observe
strictly the Warning and Caution information provided in this manual
Treat all terminals of high-voltage power equipment systems as potential
electric shock hazards. Use all practical safety precautions to prevent contact
with energized parts of the equipment and related circuits.
Use suitable barriers, barricades, or warnings to keep persons not directly
involved with the work away from test activities.
Never connect the test equipment to energized equipment.
Do not use in an explosive atmosphere.
Use the grounding and connection procedures recommended in this manual.
Always disconnect test leads from power equipment before attempting to
disconnect them at the test set. The ground connection must be the first

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made and the last removed. Any interruption of the grounding connection
can create an electrical shock hazard.
Personnel using heart pacemakers should obtain expert advice on the
possible risks before operating this equipment or being close to the
equipment during operation.
Input Power precautions
This instrument operates from a single-phase, sine wave, power source. It has a
three-wire power cord and requires a two-pole, three-terminal (live, neutral, and
ground) type input source. The voltage to ground from the live pole of the
power source must be within the following rated operating voltage:
For Cat. No TTR320 120 V ±10%, single phase sine, 50/60 ±2 Hz
For Cat. No. TTR320-47 230 V ±10%, single phase sine, 50/60 ±2 Hz
The neutral pole must be at ground potential. Before making connection to the
power source, determine that the instrument rating matches the voltage of the
power source. The power input plug must be inserted only into a mating
receptacle with a ground contact. Do not bypass the grounding connection. Any
interruption of the grounding connection can create an electric shock hazard.
Determine that the receptacle is properly wired before inserting the plug.
For test sets energized with 230 V input (TTR320-47), the neutral terminal of the
input supply cord (white or blue lead) must be connected to the neutral pole of
the line power source. The ground terminal of the input supply cord (green or
yellow/green lead) must be connected to the protective ground (earth) terminal
of the line power source. The black or brown cord lead is the live (hot) lead.
The control circuits of the instrument are protected by two mains circuit fuses.
These fuses are located in the ON/OFF switch module and are replaceable by
the operator. To avoid electric shock and fire hazard, use only the fuse specified
in Sections 1 and 8, that is identical in respect to type, voltage rating, and current
rating. Refer to the Fuse Replacement procedure in the Service section.
F WARNING
Before replacing the fuses, disconnect the
power input plug from the live power source.

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3
PREPARING FOR TEST
Site Preparation
Choose a location that meets the following conditions:
The location is as dry as possible.
There is no flammable material stored in the vicinity.
The test area is adequately ventilated.
Be sure all equipment is de-energized and all terminals of the UUT are
accessible. Erect suitable safety barriers to protect the operator from traffic
hazards and to prevent intrusion by unauthorized personnel. User provided
Warning lights are recommended.
Verify that the Local station ground is intact and has impedance continuity to
earth.
Making Circuit Connections
Connections should be made in the order as listed below.
1. Ground. Use the Megger supplied Safety Ground Cable 15 ft (4.6 m) to
connect the TTR320 Wing Nut Ground Terminal directly to Local Station
Earth ground. Ensure the Transformer chassis also has impedance
continuity to Local Station Earth ground potential.
2. Input Power Source Ground. Input Power Source Ground Terminal
should be less than 100 milliohms of impedance to Local Station Earth
Ground.
3. Connect the Input Power Cord. Before making this connection, Ensure
the Input Power Source meets the requirements as listed in Section 2 and
Specifications Section 8. Also make sure that the ON/OFF switch (Figure 1-
1, No. 1) is in the OFF position. Connect the input power cable to the
TTR320 first, then to the power source. At this time, leave the ON/OFF
switch in the OFF position.

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4. Connect the Ethernet cable (optional). If the user chooses to operate the
TTR320 in a remote-control mode, using PowerDB PC software, then
connect the Ethernet cable between the TTR320 and the PC at this time.
5. Connect the Load-Tap-Changer cable (optional). If the user chooses to
operate the “Test button” of the TTR320 from a remote distance then,
connect the LTC cable at this time.
6. Connect the H and X leads (to the TTR320 end only at this time).
With the clamps disconnected from the UUT, connect the Bayonet Plug on
the Cable labeled “H” to the TTR panel connector also labeled “H”. Repeat
this process for the “X” labeled cable. Ensure each connector is securely
fastened using a clockwise rotation.
7. Connect the H and X clamps. With the ON/OFF Switch in the OFF
position, connect the H and X clamps in accordance with Section 4 as
appropriate for the specific transformer type and test to be conducted.

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4
Connecting to the Transformer
The setup and connection instructions included in Section 4 herein, pertaining to
ratio, polarity, and phase relation, assume that the transformer under test,
connections, and terminal markings comply with the requirements of ANSI
C57.12.70-1990 American National Standards Terminal Markings and
Connections for Distribution and Power Transformers. The H test leads of the
test set are the exciting (high voltage) leads (8 V, 40 V, or 80 V). The X test
leads are the low voltage leads.
When testing high-voltage transformers, caution must be used at all times and all
safety precautions followed. Read, understand, and employ all safety precautions
and circuit connections described in Sections 2 and 3 herein.
F WARNING
Ensure that the transformer to be tested is completely
de-energized. Check every winding. Ensure that all
terminals of the transformer are disconnected from line
or load at the transformer. Connections to ground may
be left in place.
F WARNING
For all testing as described herein, care shall be taken
to ensure any and all unused clamps shall be isolated
from each other, from ground, and from personnel.
F WARNING
Except for CTs as described herein, never interchange
connections between the high- and low-voltage
transformer terminals. Failure to observe proper
connections will result in a safety hazard and may
result in damage to the test set or transformer.
Single-Phase, Two-Winding Transformers
Perform the following setup procedure for single-phase, two-winding
transformers:
1. With the ON/OFF Switch in the OFF position, make the circuit
connections as described in Section 3.

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2. Connect the H and X test cables to the respective H and X receptacles of the
TTR320. Make sure that the connectors are securely fastened (using
clockwise rotation) to the receptacles.
3. Connect the heavy-duty clamps marked H1 and H2 of the test lead to the
corresponding (high-voltage winding) terminals of the transformer under
test. Figures 4-1 and 4-2 show test setups for single-phase transformers.
Figures 4-3 and 4-4 show test setups for regulators.
4. Connect the heavy-duty clamps marked X1 and X2 of the test lead to the
corresponding (low-voltage winding) terminals of the transformer under test.
Figures 4-1 and 4-2 show test setups for single-phase transformers. Figures
4-3 and 4-4 show test setups for regulators.
5. On/OFF Switch. It is only after all of the above connections are safely
made and all safety precautions of sections 2 and 3 are satisfied, should the
On/OFF switch be turned to the ON position.
Figure 4-1.Setup for Testing Single-Phase Transformer
Figure 4-2.Setup for Testing Single-Phase Autotransformer
To test windings other than H1 – H2 and X1 – X2, ensure that the heavy-duty
clamp marked H1 is connected to the lower numbered terminal and H2 to the