TTR20

Instruction Manual AVTMTTR20 for

TTR20 Handheld TTR



Transformer Turn Ratio Test Set

Catalog No. TTR20

High-Voltage Equipment

Read the entire manual before operating.

Aparato de Alto Voltaje

Antes de operar este producto lea este manual enteramente.

M

2621 Van Buren Ave

Norristown, PA 19403-2329

610-676-8500

www.megger.com

AVTM TTR20

Rev. A

August 2005

TTR20 Handheld TTR



Transformer Turn Ratio Test Set

Instruction Manual

Copyright Notice

Copyright



2005 by Megger. All rights reserved.

Disclaimer Notice

The information contained in this manual is believed to be adequate for the intended use of the product. If the product or its individual instrument 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 included at the end of this instruction manual. 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 must be shipped prepaid and insured. 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.

TABLE OF CONTENTS

1 I

NTRODUCTION

........................................................................................................................................ 1

About the TTR20 .................................................................................................................... 1

Electrical Theory and Practice ............................................................................................. 2

Applications for the TTR20 ................................................................................................... 4

Upon Receipt of the TTR20 .................................................................................................. 5

Safety First .............................................................................................................................. 5

How to Use This Manual ....................................................................................................... 5

2 S

AFETY

.................................................................................................................................................... 7

Overview.................................................................................................................................. 7

Safety Requirements ............................................................................................................. 7

Cautions and Warnings ......................................................................................................... 8

3 C

ONTROLS

& C

ONNECTORS

................................................................................................................... 9

Overview.................................................................................................................................. 9

Connectors ............................................................................................................................10

4 S

ETUP

, C

ONNECTIONS

AND

OPERATION

.............................................................................................11

General Instructions .............................................................................................................11

Transformers .........................................................................................................................11

Single-Phase, Two -Winding Transformers ......................................................................12

Distribution Transformers with Two Secondary Windings .............................................12

Three-Phase, Two-Winding Transformers .......................................................................16

Three-Phase, Three-Winding Transformers ....................................................................16

Current Transformers (CTs) ...............................................................................................17

General Operating Procedure ............................................................................................20

Description of Menus and Test Screens ...........................................................................20

Use with the Optional Printer..............................................................................................23

HyperTerminal Configuration .............................................................................................25

AVTMTTR20 Rev A AUGUST 2005 i

5 M

AINTENANCE AND

T

ROUBLESHOOTING

...............................................................................................27

Maintenance..........................................................................................................................27

Calibration Check .................................................................................................................27

TTR20 Functional Test........................................................................................................28

Battery Replacement ...........................................................................................................29

Troubleshooting ....................................................................................................................30

Error Messages ....................................................................................................................31

Repair.....................................................................................................................................33

A

PPENDIX

A S

PECIFICATIONS

................................................................................................................35

Electrical ................................................................................................................................35

Environmental Conditions ...................................................................................................37

Physical Data ........................................................................................................................37

Optional Accessories ...........................................................................................................38

A

PPENDIX

B O

RDERING

I

NFORMATION

& S

PARE

P

ARTS

L

IST

...............................................................39

A

PPENDIX

C C

ONNECTIONS AND

V

ECTOR

V

OLTAGE

D

IAGRAMS

..........................................................41

ii

AVTMTTR20 Rev A AUGUST 2005

LIST OF ILLUSTRATIONS

Figure 1-1. TTR20 Single-Phase Test Set Block Diagram ............................................................ 4

Figure 3-1 TTR20 Display & Control Panel ..................................................................................... 9

Figure 3-2 TTR20 Top Side Connector Panel ..............................................................................10

Figure 4-1 Setup for Testing Single-Phase Transformer ............................................................13

Figure 4-2 Setup for Testing Single-Phase Autotransformer .....................................................13

Figure 4-3 Setup for Testing Single-Phase, Type A Step Voltage Regulator ..........................14

Figure 4-4 Setup for Testing Single-Phase, Type B Step Voltage Regulator ..........................14

Figure 4-5 Setup for Testing X1 – X2 Winding of Distribution Transformer.............................15



Figure 4-8 Setup for Testing Unmounted Current Transformer.................................................18

Figure 4-9 Setup for Testing Taps on Multiple Tap CT...............................................................18

Figure 4-10 Setup for Testing BCT Mounted on Single -Phase Two-Winding Transformer.....19

Figure 4-11 TTR20 Opening Display Screen..................................................................................20

Figure 4-12 Start Test Screen ...........................................................................................................21

Figure 4-13 Test in Progress Screen................................................................................................22

Figure 4-14 TTR20 Test Result Screen ...........................................................................................22

Figure 4-15 Sample Test Report .......................................................................................................23

Figure 4-16 Printer Configuration Printout .......................................................................................24

AVTMTTR20 Rev A AUGUST 2005 iii

LIST OF TABLES

Table 5-1 Troubleshooting Guide....................................................................................................30

Table 5 -2 Self-test Error Messages ................................................................................................31

Table 5 -3 Test Error Messages .......................................................................................................31

Table 5 -4 Miscellaneous Message .................................................................................................32

Table C-1 ANSI Transformer Winding Phase Relationship ........................................................42

Table C-2 ANSI Transformer Winding Phase Relationship ........................................................44 iv


1

INTRODUCTION

About the TTR20

The TTR20 Handheld TTR

®

Test Set is a fully automatic, self-checking, selfcalibrating unit. The test set measures the turn ratio, excitation current, and phase displacement (polarity) of single- and three-phase (phase by phase) distribution transformers, as well as power, potential and current transformers.

The TTR20 Handheld TTR

®

Test Set is powered by six AA-size disposable alkaline batteries. The test set is a portable instrument housed in a sturdy plastic case. A carrying case with strap and an accessory pouch is provided with the test set.

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 transformers, the test set is connected to each of the three phases of the transformer to be tested, and measurements are made on a phase by phase basis.

Turn ratio, phase displacement (polarity), and excitation current are displayed on a large LCD. Transformer excitation current 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 printed out on an optional printer.

Features include:

§

Fully automatic operation.

§ Self-checking at power-up.

§ Self-calibration at each measurement.

§

User-friendly, one button operation.

§ Test turn ratio, excitation current, and phase displacement (polarity).


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§ Easy measuring of single and three phase (phase by phase) transformers, as well as potential & current transformers.

§

Checking reverse test lead or winding connections at start of each test.

§ External optional printer records test data.

§ Three automatically selected excitation test voltages: 8 V, 1.5 V, and 0.5 V.

§ Testing to ANSI standards.

§

Leads marked to ANSI standards.

§ Large, easy-to-read LCD shows alphanumeric data

§ Meets the requirements of both the European EMC and Low Voltage Directives

(CE mark).

§ Trouble -free operation in switchyards under electrostatic and magnetic interference conditions.

Electrical Theory and Practice

How the TTR20 Works

The TTR20 test set provides the excitation voltage to the input of the transformer.

It accurately measures both the H-side and X-side voltages to calculate turns ratio. The TTR also measures phase displacement (polarity) between primary and secondary windings of a transformer, and transformer excitation current.

Transformer Turns Ratio

Transformer Turns Ratio is the ratio of the number of turns in the high voltage winding to that in the low voltage winding. Transformer ratio can change due to several factors, including physical damage from faults, deteriorated insulation, contamination and shipping damage.

A Transformer Turns Ratio Test Set such as the TTR20 can directly measure the turns ratio of single -phase transformers as well as three-phase transformers.

Deviations in these measurements will quickly indicate problems in transformer windings and in the magnetic core circuits. If a transformer ratio deviates more than 0.5 percent from the rated voltage ratio, it may not operate reliably. To measure small ratio changes such as this, the accuracy of a Megger TTR20 is needed.

Excitation Current

The TTR20 is capable of measuring exciting current by applying voltage to one of the transformer’s windings. An accurate measurement of exciting current can provide information about the condition of a transformer’s core. Unwanted


2

INTRODUCTION

circulating currents, unintentional grounds or even an incipient short circuit can affect the exciting current and indicate a problem.

Transformer Polarity

Polarity of a distribution transformer becomes of interest in order to determine its proper connection within a power network. The Megger TTR20 will identify normal (in phase) and reverse polarity of the single -phase transformers.

A block diagram of TTR20 is shown in Figure 1-1. The excitation voltage oscillator applies a 55-Hz test voltage to a transformer under test. There are three test voltages: 0.5 V, 1.5 V, and 8 V used for transformer testing. Test voltage selection is based on excitation current required. The required test voltage is selected automatically.

Input and output transformer voltages are applied to conditioning circuitry. This circuitry improves signal-to-noise ratio of the test signal, and provides full voltage range of the test signals at A/D converter inputs.

A/D converter is used to convert the analog measurement signals to their digital replica. The converted output digital signals are applied to CPLD (complex programmable logic device) and then are transferred to microprocessor.

The microprocessor is the main part of the TTR test set. It provides proper timing sequence of operation, gathers and calculates the test result, and interfaces with peripherals. There are three main peripherals in the TTR20 test set:

RS-232/Printer port, LCD and keypad.

DC power supply converts the primary battery voltage, six Energizer

®

X91 AAalkaline batteries, 9 V (nominal), 3135 mAh nominal capacity, into the secondary

DC voltages required for proper operation of the TTR20 test set.


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Transformer

Under Test

Input/Output

Signal

Conditioning

Circuitry

Exc. Voltage

Oscillator

CPLD MICROPROCESSOR

A/D

Converter

RS232/Printer

Port

128 x 64 LCD

Keypad

DC Power

Supply

Figure 1-1. TTR20 Test Set Block Diagram

Applications for the TTR20

The proper operation of a transformer relies almost entirely on the electrical properties of its windings. To ensure continued proper operation, transformers are tested to verify that their electrical properties have not changed from design specifications. A TTR is an extremely useful instrument for testing transformer windings because it can help locate several types of problems within single - and three-phase transformers.

It is used to determine the no-load accuracy of CTs and PTs and also determine the need to further test faulty CTs and PTs.

The TTR20 applies voltage to the high-voltage winding of a transformer and accurately measures the resulting voltage from the low voltage winding. The ratio of voltages is directly proportional to turns ratio. In addition, the unit measures excitation current and polarity.


4

INTRODUCTION

Upon Receipt of the TTR20

Check the equipment received against the packing list to ensure that all materials are present. Notify Megger of any shortage. Telephone 610-676-8500.

Examine the instrument for damage received in transit. If any damage is discovered, file a claim with the carrier at once and notify Megger or its nearest authorized sales representative, giving a detailed description of the damage.

This instrument has been thoroughly tested and inspected to meet rigid specifications before being shipped. It is ready for use when set up as indicated in this manual.

Safety First

Be sure to read the safety information in Chapter 2 thoroughly and observe all safety precautions and recommendations.

How to Use This Manual

Typographic Conventions

G

CAUTION

Cautions alert you to possible damage to equipment.

WARNING

F

Warnings alert you to conditions that are potentially hazardous to people.

NOTE: Notes provide important information.


5

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6


2

SAFETY

Overview

The TTR20 must be used on de-energized transformers. However, the transformer to which the test set is connected is a possible source of highvoltage electrical energy and all persons making or assisting in tests must use all practical safety precautions to prevent contact with potentially energized parts of the transformer and related circuits. Persons actually engaged in the test must stand clear of all parts of the complete high-voltage circuit, including all connections, unless the test set is de-energized and all parts of the test circuit are grounded. Persons not directly involved with the work must be kept away from test activities by suitable barriers, barricades, or warnings.

Treat all terminals of high-voltage power equipment as a potential electric shock hazard. There is always the possibility of voltages being induced at these terminals because of proximity to energized high-voltage lines or equipment.

Always disconnect test leads from power equipment before attempting to disconnect them at the test set. The ground connection must be the first made and the last removed. Any interruption of the grounding connection can create an electric shock hazard.

Any repair or component replacement must be performed by qualified service personnel.

Safety Requirements

Megger has made formal safety reviews of the initial design and any subsequent changes. This procedure is followed for all new products and covers areas in addition to those included in applicable standards. Regardless of these efforts, it is not possible to eliminate all hazards from electrical test equipment. For this reason, every effort has been made to point out in this instruction manual the proper procedures and p recautions to be followed by the user in operating this equipment and to mark the equipment itself with precautionary warnings where appropriate. It is not possible to foresee every hazard that may occur in the various applications of this equipment. It is therefore essential that the user, in


7

M addition to following the safety rules in this manual, also carefully consider all safety aspects of the test before proceeding.

§ Safety is the responsibility of the user.

§ Follow your company safety procedures.

§ Misuse of this equipment can be extremely dangerous.

§ The purpose of this equipment is limited to use as described in this manual. Do not use the equipment or its accessories with any device other than specifically described.

§ Never connect the test set to energized equipment.

§

Do not use the test set in an explosive atmosphere.

§ Corrective maintenance must only be performed by qualified personnel who are familiar with the construction and operation of the test set and the hazards involved.

§ Refer to IEEE 510 - 1983, IEEE Recommended Practices for Safety in High-

Voltage and High-Power Testing, for additional information.

If the test equipment is operated properly and all grounds correctly made, test personnel need not wear rubber gloves. As a routine safety procedure, however, some users require that rubber gloves be worn, not only when making connections to the high-voltage terminals, but also when manipulating the controls. Megger considers this an excellent safety practice.

Users of equipment should note that high-voltage discharges and other sources of strong electric or magnetic field may interfere with the proper functioning of heart pacemakers. Persons with heart pacemakers should obtain expert advice on the possible risks before operating this equipment or being close to the equipment during operation.

Cautions and Warnings

Warning and caution notices are used throughout this manual where applicable and should be strictly observed.


8

3

CONTROLS & CONNECTORS

Overview

The TTR20 is a simple, push-to-test instrument with few buttons and controls. It has no menus except for a print button.

Contrast

Backlight

This knob adjusts the viewing resolution of the screen.

A momentary depression of the switch will either activate or de-activate the backlight. It will remain ON for a period of three minutes without activity.

Power ON Switch

Press this switch to turn the TTR20 on.

Power OFF Switch

Press this switch to turn the TTR20 off.

DISPLAY SCREEN

LCD displays menus and test information.

KEYPAD

4-button keypad for entering menu selections and navigating through the various screens.

Display Screen

CONTRAST

Back Light switch

Power OFF switch

Keypad

Power ON switch

Figure 3-1 TTR20 Display & Control Panel


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Connectors

PRINTER

TEST CABLE

Figure 3-2 TTR20 Top Side Connector Panel

TEST CABLE

Plug receptacle for connecting test leads to the high-voltage (H) and low-voltage (X) windings of a transformer. The plug and receptacle are keyed to prevent the cable from being inserted incorrectly, and to make certain that the correct cable is used.

RS-232/PRINTER

A DB-9 male connector for connecting a printer or to upload data in real time to a PC (using

HyperTerminal).

10


4

SETUP, CONNECTIONS AND OPERATION

General Instructions

When testing high-voltage transformers, caution must be used at all times and all safety precautions followed. Read and understand all safety information contained in Section 2, Safety.

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. For some transformers, connections to ground may be left in place.

F

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.

Check that a lead set connected is labeled for TTR20 test set operation.

The TTR20 has been designed to test a variety of transformers, such as: Single phase, Three phase (one phase at a time), CTs, PTs and Voltage Regulators.

Do not leave the TTR20 test set exposed below -20

0

C or above 55

0

C for more than 2 hours. Such conditions will lead to shortened service life of batteries.

When storing the TTR20 at temperatures below -20

0

C or above 55

0

C, remove the batteries. See Battery Replacement for detail.

Transformers

The setup and connection instructions pertaining to ratio, polarity, and phase relation assume that the transformer under test, connections, and terminal markings comply with the requirements of ANSI C57.12.70-1978 American

National Standards Terminal Markings and Connections for Distribution and

Power Transformers. The H leads of the test cable are the exciting leads.


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The TTR20 may supply up to 100 mA of excitation current. The TTR20 will automatically select the appropriate test voltage (8 V, 1.5 V, or 0.5 V) when testing transformers.

Single-Phase, Two-Winding Transformers

Perform the following setup procedure for single-phase, two-winding transformers:

1. Connect the test lead set to the TEST CABLE receptacle of the TTR20 test set. Make sure that the connector is fully engaged into the receptacle.

2. Connect the clips marked H1 and H2 of the test lead to the corresponding

(high-voltage winding) terminals of the transformer under test.

3. Connect the clips marked X1, 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 voltage regulators.

NOTE: When properly connected, expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result).

If the sign is "-", then check the lead connections.

Distribution Transformers with Two Secondary Windings

The TTR20 may test the turn ratios of distribution transformer secondary windings (one at a time). Perform the following setup procedure for single-phase distribution transformer with two secondary windings:

1. Connect the test lead set to the TEST CABLE receptacle of the TTR20 test set. Make sure that the connector is fully engaged into the receptacle.

2. Connect the clips marked H1 and H2 of the test lead to the corresponding


3. When testing X1-X2 winding, connect, respectively, the clips marked X1 and X2 of the test lead to the X1 and X2 terminals of the transformer under test. Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result). ). See Figure 4-5.

4. When testing X3-X2 winding, connect the X1 clip to X3 transformer terminal, and connect the X2 clip to X2 transformer terminal. Expect that


12

Setup, Connections & Operation

polarity of the windings is reversed (“-” sign is displayed in front of the turns ratio test result). See Figure 4-6.

5. When testing full secondary winding (X1 – X3), connect X1 clip to X1 terminal, connect X2 clip to X3 terminal. Remove the ground connection to

X2 transformer terminal before starting the test. Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result). See Figure 4-7.

H1 LEAD

X1 LEAD

H1

X1

TTR20

H2 LEAD

H2 X2

TRANSFORMER

X2 LEAD

Figure 4-1 Setup for Testing Single-Phase Transformer

TTR20

H1 LEAD

H1

X1 LEAD

X1

H2 LEAD

X2 LEAD

H2

X2

AUTOTRANSFORMER

Figure 4-2 Setup for Testing Single-Phase Autotransformer


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TTR20

H1 LEAD

SOURCE

S

SHUNT

WINDING

SERIES

WINDING

X1 LEAD

"RAISE"

DIRECTION

L

R

L

LOAD

H2 LEAD

SL

COMMON

Figure 4-3 Setup for Testing Single-Phase, Type A (Straight Design) Step Voltage Regulator

SERIES

WINDING

X1 LEAD

TTR20

SOURCE

S

H1 LEAD

"RAISE"

DIRECTION

R

L

L

LOAD

SHUNT

WINDING

H2 LEAD

X2 LEAD

SL

COMMON

Figure 4-4 Setup for Testing Single-Phase, Type B (Inverted Design) Step Voltage Regulator


14


H1 LEAD

H1 X1

X1 LEAD

TTR20

X2

X2 LEAD

H2

H2 LEAD

X3

Figure 4-5 Setup for Testing X1 – X2 Winding of Distribution Transformer

(H2 and X2 Grounded)

H1 LEAD

H1 X1

X2 LEAD

TTR20

X2

H2

H2 LEAD

X3

X1 LEAD


(H2 and X2 Grounded)

H1 LEAD

H1 X1

X1 LEAD

TTR20

H2 LEAD

H2

X2

X3

Remove Ground

Connection

X2 LEAD



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Three-Phase, Two-Winding Transformers

Perform the following setup procedure for three-phase, two -winding transformers:

1. Connect the test cables to the test set.

2. Connect the clips marked H1 and H2 of the test lead to the phase being tested


3. Connect the clips marked X1 and X2 of the test lead to the phase being tested

(low-voltage winding) terminals of the transformer under test.

F

WARNING


The unused H0 and X0 terminals of the transformer should be kept clear of ground and personnel because they could become energized during the test.

With wye connected windings, a neutral connection is normally available.

Three-Phase, Three-Winding Transformers

This type of transformers has primary, secondary and tertiary windings. Primary and secondary windings are tested as a regular three-phase, two-winding transformer. To test tertiary winding, perform the following setup procedure:

1. Connect the test cables to the test set.

2. Connect the clips marked H1 and H2 of the test lead to the phase being tested


3. Connect the clips marked X1 and X2 of the test lead to the corresponding tertiary phase being tested (low-voltage winding) terminals (Y1 and Y2) of the transformer under test.

F

WARNING


With wye connected windings, a neutral connection is normally available.


16


Current Transformers (CTs)

Connections to CTs are made backwards compared to power, distribution or potential transformers. The H terminals on the test lead set must be connected to the X terminals on the CT; and the X terminals on the test lead set must be connected to the H terminals on the CT.

NOTE: Dots on the housing of the transformer are commonly used to identify terminals of the same polarity.

F

WARNING

Failure to observe proper connections will result in a safety hazard and may result in damage to the test set or CT. Failure to observe voltage rating of low-current X winding may result in damage to the CT.

NOTES:

1.

The TTR20 may supply up to 100 mA of excitation current. The TTR20 will automatically select the appropriate test voltage (8 V, 1.5 V, or 0.5

V) when testing CTs. Some current transformers with turn ratio of 50:5 and less may require more than 100 mA of excitation current when excited from 0.5 V source. These CTs can not be tested with the TTR20.

2.

Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result).


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Unmounted CTs

NOTE: The illustrated connection diagrams are provided as connection guides and do not suggest the physical location of the bushings / terminals of the device being tested.

Figure 4-8 shows the setup for testing unmounted current transformers.

Figure 4-9 shows the setup for testing the taps on a multiple-tap CT.

POLARITY

DOT

H1 LEAD H2 LEAD

X1 X2

H2

X2 LEAD

BUS OR USE

HEAVY GAUGE

LEAD WIRE

H1

CT

X1 LEAD

Figure 4-8 Setup for Testing Unmounted Current Transformer

H1 LEAD

X1

X1 LEAD

X2

H1

X1 LEAD

TTR20

X3

H2

X1 LEAD

X4

X5

TRANSFORMER

Figure 4-9 Setup for Testing Taps on Multiple Tap CT


18


Bushing Current Transformer (BCT) Mounted on Single-Phase, Two-

Winding Transformer

A turn-ratio test can be performed on a BCT after it has been mounted on a circuit breaker or power transformer entrance bushing. The test can be performed without removal of the BCT from the equipment. Connect the TTR20 to BCT as shown in Figure 4-10.

NOTES:

1. Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result).

2. A jumper lead is not supplied with the TTR20.

BCT POLARITY MARKER (TYP)

X1 LEAD

H1

X1

X2

H2

BCT

JUMPER

LEAD

H1 LEAD

H2 LEAD

X2 LEAD

POWER

TRANSFORMER

Figure 4-10 Setup for Testing BCT Mounted on Single-Phase Two -Winding Transformer


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General Operating Procedure

Proceed only after reading and fully understanding Section 2, Safety, and setting up the test set as described. An operator who is familiar with the contents of this manual, the test setup, and the operation of the test set may follow the condensed operating instructions provided with the test set.

EMERGENCY SHUTDOWN

(Removal of Test Voltage from device being tested.)

Press RED KEY on the keypad to terminate test.

Description of Menusand Test Screens

Data shown on the menus and test screens in Figures 4-11 through 4-14 are for illustrative purposes only. The TTR20 test set menus and test screens are operated by using the keypad. On power up, the test set performs a self-test check, and all hardware and software variables are initialized.

Opening Display Screen

The LCD displays the opening screen (Figure 4-11) as the test set performs a diagnostic self-check of the electronics.

MEGGER

TRANSFORMER

TURN-RATIO TEST SET

TTR20

VERSION : 1.01

SELF-TEST IN PROGRESS

COPYRIGHT 2005

ALL RIGHTS RESERVED

Figure 4-11 TTR20 Opening Display Screen

If at power-up self-testing any errors are detected, one of the error messages listed in the ERROR MESSAGES section will be displayed on the screen.


20


If no errors are detected, the screen showing a battery charge level, in % of full charge, is displayed for 3 sec. If battery level is above 10 %, the START TEST screen (Figure 4-12) appears.

If battery level is below 10 %, the message “BATTERY LEVEL:LOW, APPR.1HR

OF OPERATION REMAINING…” appears on the screen for 3 sec. A customer may continue testing of transformers. The remaining battery capacity is enough for approximately one hour of operation.

If battery level is below 5%, the message “REPLACE BATTERY! UNIT WILL

TURN OFF” appears on the screen. In 10 sec. the TTR20 shuts down. Replace the batteries (six AA-size disposable alkaline batteries) before further attempting to initiate the TTR20 operation.

Start Test Screen

After a successful self-test check, the START TEST screen (Figure 4-12) appears.

-- CONNECT TEST LEADS

TO TRANSFORMER,

-- ? TO START TEST

Figure 4-12 Start Test Screen

When ? is pressed on a keypad, the test starts and the TEST IN PROGRESS screen (Figure 4-13) appears.


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Test in Progress Screen

Figure 4-13 shows the TEST IN PROGRESS screen.

TEST IN PROGRESS…

PRESS RED BUTTON FOR

EMERGENCY SHUTDOWN

Figure 4-13 Test in Progress Screen

If during testing a n abnormal condition is detected, one of the error messages listed in the ERROR MESSAGES section is displayed on the screen.

In case of emergency, press the red button on keypad. It will turn TTR20 OFF.

After emergency situation is gone, turn power ON (green button) to start TTR20 operation.

Test Result Screen

At the completion of the test, the TEST RESULTS screen (Figure 4-14) appears.

TEST RESULTS

TEST VOLTAGE: 1.5 V

TURNS RATIO: +12.735

EXC. CURRENT: 34 µA

“

8

“ TO PRINT

“

?

“ FOR NEW TEST

Figure 4-14 TTR20 Test Result Screen

The TEST RESULTS screen displays the test voltage used for the test, the measured turns ratio, the tested winding polarity (“+” for in phase or normal polarity, and ”-“ for out of phase or reversed polarity), and the tested winding excitation current.

From this screen, the test results may be printed out on the optional printer connected to RS232/PRINTER port of the TTR20.


22


To repeat the test or to start a new one, press the

?

button on a keypad.

Use with the Optional Printer

If you are using the optional printer, plug the printer cable supplied into the

RS232/PRINTER receptacle on the TTR20 test set and turn it on. A separate manual is supplied with the printer. Refer to it for specific information about how to connect, operate, and care for the printer.

NOTE: TTR20 should be turned on before turning on a printer.

Header information and test results may be printed from the test results screen

MEGGER

TTR20 TRANSFORMER TURN RATIO TESTER

CATALOG NO. TTR20

TRANSFORMER ID:

TTR S/N:

COMMENTS:

TEST RESULTS

TEST VOLTAGE: 8.0 V

TURNS RATIO:+69.966

EXC.CURRENT: 96.4µA

TEST RESULTS

TEST VOLTAGE: 8.0 V

TURNS RATIO:+79.966

EXC.CURRENT: 94.4µA

Figure 4-15 Sample Test Report


23

M

Configuration

To print a paper copy of the existing printer settings:

While holding down the "On-Line" switch, turn on the printer. The following list will print (factory default settings shown).

Figure 4-16 Printer Configuration Printout

24



If you want to leave the settings as they are, press the "FEED" switch.

If you need to change a setting, press the "ON LINE" switch to enter the reconfiguration mode. For each group of switches, press the "FEED" switch if all the settings are okay. Press the "ON LINE" switch if a setting needs to be changed. At an individual setting, press the "FEED" switch if it is okay and press

"ON LINE" to change that setting.

HyperTerminal Configuration

The following is the HyperTerminal configuration:

Baud: 19,200

Data Bits:

Parity:

8

None

Stop Bits: 1

Flow Control: None


25

M

M

26


5

MAINTENANCE AND TROUBLESHOOTING

Maintenance

Maintenance should be performed only by qualified persons familiar with the hazards involved with high-voltage test equipment. Read and understand Section

2, Safety, before performing any service.

The TTR20 test set is sturdily constructed and requires no periodic maintenance.

Routine maintenance is all that is required for the TTR test sets. Inspect the cable assemblies occasionally to ensure they are in good condition.

The appearance of the TTR test set can be maintained by occasionally cleaning the case, panel and cable assemblies. Clean the outside of the carrying case with detergent and water. Dry with a clean, dry cloth. Clean the control panel with a cloth dampened with detergent and water. Do not allow water to penetrate panel holes, because damage to components on the underside may result. An all-purpose, household spray cleaner can be used to clean the panel. Polish with a soft, dry cloth, taking care not to scratch the display screen cover. Clean the cables and mating panel receptacles with isopropyl or denatured alcohol applied with a clean cloth.

Calibration Check

A complete performance and calibration check should be made at least once every year. This will ensure that the TTR20 test set is functioning and calibrated properly over the entire measurement range. The TTR20 calibration is performed on each new or repaired unit before sending it to a customer. There is a special

TTR20 final calibration procedure which requires a NIST-traceable test equipment to be used. As a result of such calibration procedure, each TTR20 may be NIST certified.

To check the TTR20 calibration at a customer site or in the field, the Megger

Calibration Standard Cat.No550055 or equivalent standard should be used. To perform a quick simplified calibration check, the Megger Calibration Standard

CatNo550555 may be used. The last standard has eleven switchable turn ratio settings which cover the turns ratio range from 1:1 to 2000:1. Using these

Calibration Standards will confirm proper calibration of TTR20.


27

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TTR20 Functional Test

A customer may want to make sure that the test set is functioning properly before testing a transformer. Traditionally, for the transformer turns ratio testers, a customer performed this test by connecting H1-X1 and H2-X2 test leads. The 1:1 turns ratio was expected to be measured. Additionally, the displayed test results were interpreted as a test set calibration check.

TTR20 test set is designed and optimized for the transformer turns ratio testing. It uses a mixed analog-digital technique to provide the accurate readings of the tested transformer turns ratio. The test set measurement approach is based on high impedance input and output transformer voltage monitoring circuits. The high impedance of the monitoring circuits is optimized for the accurate transformer turns ratio testing.

When performing a TTR20 functional test, the H and X test leads interconnect the input and output monitoring circuits without a transformer being connected.

Such connection cause an impedance mismatch and, as a result of the mismatch, the displayed turns ratio reading is not exactly 1:1 as it may be expected. A customer should be aware that a functional test is not a real transformer turns ratio test. Due to the intrinsic and inevitable impedance mismatching, the TTR20 functional test readings may be from 0.9980 to 1.0020.

The TTR20 functional test readings do not represent the TTR20 calibration. It simply shows that the TTR20 test set circuitry functions properly. To check the

TTR20 calibration, a customer should use the Calibration Standards mentioned in the Calibration section of the manual.

To perform a TTR20 functional test proceed as follows:

1. Turn TTR20 power on (green button on a keypad).

2. Connect H1 lead to X1 lead, and H2 lead to X2 lead.

3. After self-test is complete and start test screen appears, press

?

to start testing.

NOTE: This is not a 1:1 ratio calibration check due to different impedances between the instrument's H-side circuitry and X-side circuitry.

F

and personnel.

WARNING

4. Turn ratio reading on the test results screen should be from +0.9980 to

+1.0020.


28

Maintenance and Troubleshooting

Battery Replacement

TTR20 test set is powered up from six AA-size disposable alkaline batteries. A battery holder (contained six batteries) is installed in a battery compartment on the back side of the instrument housing. The compartment door is fixed to the housing by two screws.

To replace the batteries proceed as follows:

1. Remove the battery compartment door.

2. Lift up a battery holder from the compartment. Unplug a battery strap.

3. Replace all six batteries by the new ones. Use AA-size disposable alkaline batteries only. Observe the proper polarity of the batteries. A negative battery terminal (flat bottom portion of battery) should be placed against a battery holder spring. The batteries should be installed in series. See a battery holder for proper polarity and battery installation orientation.

4. Connect a battery strap back to the battery holder. Install the battery holder into the compartment.

5. Replace the battery compartment door and secure it with screws.

6. Turn on TTR20. It should display the opening screen, then the battery level screen. The battery level displayed depends on many factors including type of battery installed, battery manufacturing date, battery storing conditions, etc. In average, the new battery level displayed should be above 80 %.

NOTE: The TTR20 is delivered with high-capacity (3135 mAh)

"Titanium" batteries installed. The specified operating time of 12 hours is based on using these high-capacity batteries or equivalent.


29

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Troubleshooting

The Troubleshooting Guide, Table 5-1, is arranged to help you evaluate the reasons for TTR20 test set malfunction. The table lists possible TTR20 test set malfunctions which may be encountered during operation and lists possible causes. Electronic circuit repairs should not be attempted in the field. Refer to

Repair section. Refer to Appendix B for a list of spare parts.

Table 5-1 Troubleshooting Guide

MALFUNCTION POSSIBLE CAUSE

Display stays blank after POWER switch is turned on.

Battery is discharged.

CONTRAST potentiometer not adjusted.

Defective display or electronics.

Any error message on the screens See ERROR MESSAGES section

Test results erratic

Defective test leads (open circuit, poor connection).

Problem in test specimen (poor connection).

Problem in TTR20 measuring circuit.

Incorrect connection of leads.

Incorrect marking of a transformer.

Defective transformer.

Printer power not turned on.

Can not obtain printout when printer is connected.

Printer battery discharged.

Problem in TTR20 printer interface electronics.

Printer cable is defective or is a null-modem cable.


30


Error Messages

All TTR20 error messages are divided by 3 categories: self-test error messages, test error messages, and miscellaneous error messages.

The self-test error messages may appear on the opening screen during power-up self-test procedure. The Table 5-2 below shows the messages.

Error Message

Table 5-2 Self-test Error Messages

Description of error and action required

UNIT INOPERATIVE One of the power supply voltages is too low, or A/D converter is not working for the reference oscillator. Contact the factory for repair.

REPLACE BATTERY!

UNIT WILL TURN OFF

The remaining battery capacity is less than 5

%. Unit will turn off in 10 sec. Replace all six batteries. After the batteries are replaced, continue testing.

The test error messages may appear on the screens during testing of transformer. The Table 5-3 below shows the messages.

Error Message

Table 5-3 Test Error Messages


REPLACE BATTERY!

UNIT WILL TURN OFF

EXC.CURRENT TOO

HIGH

The remaining battery capacity is less than 5 %.

Unit will turn off in 10 sec. Replace all six batteries. After the batteries are replaced, continue testing.

Excitation current is higher than 100 mA. Check for any wrong test cable connections or transformer winding shorts.


31

M

Error Message Description of error and action required

CHECK CONNECTIONS The test leads are not properly connected to transformer. Connect the leads properly.

Test lead(s) is open. Contact the factory for repair.

Transformer winding(s) is open. Fix the problem before continuing the test.

CONNECTIONS

REVERSED

TURN RATIO >10,000

H and X test lead connections are reversed.

Connect H and X test leads properly.

TURN RATIO < 0.8

The tested turns ratio is higher than 10,000:1.

Causes test to stop. Check for bad or open test lead connections.

Transformer winding(s) is open. Fix the problem before continuing the test.

The tested turns ratio is less than 0.8:1. Causes test to stop. Check for bad or shorted test lead connections.

Transformer has a winding turn(s) shorted. Fix the problem before continuing the test.

UNIT NOT CALIBRATED Tested turns ration is not calibrated. Contact factory for possible problem(s).

The miscellaneous error message may appear on the screens during printing functions. The Table 5-4 below shows the message.

Error

Message

Table 5-4 Miscellaneous Message


PRINT

ERROR

There was an error during printing a report. Try again. See

Table 5.1. If failed, contact the factory for repair.

When an error message appears on a screen indicating an abnormal operating condition, verify the condition by taking a repeat measurement before attempting


32

Repair


to take any corrective action. Also, refer to the Troubleshooting section for malfunctions and possible causes.

Open connections, wrong connections, open windings, shorted windings, high resistance windings, other abnormal transformer problems, or a combination of these may cause a large deviation from nominal turn ratio or indicate an unusual message. The unusual operating conditions may be caused by an abnormal leakage reactance or capacitive coupling within the transformer windings.

Megger offers a complete repair and calibration service and recommends that its customers take advantage of this service in the event of equipment malfunction.

Contact your Megger representative for instructions and a return authorization

(RA) number. Equipment returned for repair should be shipped prepaid and insured and marked for the attention of the Repair Department. Please indicate all pertinent information including problem symptoms and attempted repairs. The catalog number and serial number of the test set should also be specified. Pack the TTR test set, including all cables, in a carton (original shipping carton if available) with adequate dunnage in accordance with best commercial practice.

Seal the carton with waterproof tape.

Ship to: Megger

Attn: Repair Dept, RMA #

Valley Forge Corporate Center

2621 Van Buren Avenue

Norristown, PA 19403 USA

1-610-676-8500


33

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34


Appendix A

SPECIFICATIONS

Electrical

Type of Power

Six AA-size disposable alkaline batteries

12 hrs of continuous field operation when new Energizer

®

X91 batteries or equivalent (with average capacity of 3135 mAh) are used

Pollution Degree

TTR20 is designed for Pollution Degree II

Regulatory Compliance

IEC 61010-1

Environmental Protection

Dust and shower protection to IP54

Output Test Voltage and Current

3 test voltages, auto matically selected: 8V rms, 1.5V rms or 0.5V rms

Test current: up to 100 mA

Test Frequency

55Hz, internally generated providing a universal 50 / 60 Hz test set.

Loading of Test Transformer

Less than 0.1 VA


35

M

Measuring Ranges

Turn ratio: 0.8:1 to 10,000:1, 5 digit resolution

Current: 0 to 100 mA, 4 digit resolution

Transformer Polarity: NORMAL (in phase) or REVERSE (out of phase)

Accuracy

Turn ratio: ±0.1% (0.8 to 2000)

±0.15% (2001 to 4000)

±0.25% (4001 to 10,000)

Measurement Method

Current (rms): ±(2% of reading + 1 digit)

In accordance with ANSI/IEEE C57.12.90

Transformer Winding Phase Relationship

ANSI C57.12.70-1978

CEI/IEC 76-1:1993 and Publication 616:1978

Measuring Time

4 sec for turns ratio, excitation current, and phase displacement (polarity) testing.

Display

Wide temperature range LCD module, 128 x 64 dots, 21 characters by 8 lines.

36


Appendix A

Interface

Printer port: DB-9 male connector

Cable used: 9-pin D-type connectors, standard extension female-female RS232 cable (for TTR20 to a PC connection. The cable is not included in accessory supplied);

9-pin D-type connectors, null modem female-male

RS232 cable (for the optional serial printer connection. The cable is included in optional printer package)

Data exchange rate: up to 57.6 Kbaud for the field firmware upgrading and 19.2 Kbaud for test report printing on the optional serial printer

Environmental Conditions

Operating temperature range:

Storage temperature range:

Relative humidity:

-15 to 55

°

C (5

°

to 130

°

F)

-50 to 60

°

C (-60

°

to 140

°

F) to 90% noncondensing (operating)

95% noncondensing (storage)

Physical Data

Dimensions: (240 x 115 x 50 mm) (H x W x D)

9.5 x 4.5 x 1.9 in.

Weight

Test Set: 890 g (1.9 lbs.) with Leads 1.4 kg (3.1 lbs.)


37

M

Optional Accessories

§ Battery/line-powered serial thermal printer package for 120 V ac

(p/n 35755-1). The package includes the thermal printer, a battery pack, an AC adapter and an interface cable.

§ Battery/line-powered serial thermal printer package for 230 V ac

(p/n 35755-2). The package includes the thermal printer, a battery pack, an AC adapter and interface cable.

§ Lead sets for single phase transformer testing, shielded, heavy-duty clip-end terminated. The leads are marked according to ANSI Standards.

§

Additional printer paper, one roll, (p/n 26999)

§ USB Serial Adapter (p/n 35871) for connecting a TTR20 RS232 port to a PC

USB port. The adapter is used if a PC does not have an RS232 port.

§ Battery Replacement (six required) p/n 35956

38


Appendix B

ORDERING INFORMATION & SPARE PARTS LIST

Ordering Information

Item

TTR20 Transformer Turns Ratio Test Set

Included Accessories

Canvas carrying bag and Accessory Pouch

Cat. No.

TTR20

55-20008

35956

35938

Battery ( six AA-size disposable alkaline batteries included)

TTR20 Lead Set, 1.8 m (6 ft)

Instruction manual

Optional Accessories

AVTMTTR20

Battery/line-powered, serial, thermal-printer package, 120 V ac 35755-1

Battery/line-powered, serial, thermal-printer package, 230 V ac 35755-2

RS232 cable for connecting to a PC (for firmware upgrading) 33147-18

TTR20 Lead Set, 3.6 m (12 ft) 35942

TTR20 Lead Set, 6 m (20 ft)


Semi-hard fabric transport case

36013

36042

35788

Battery replacement (six required)

Additional printer paper, 1 roll

USB Serial adapter

35956

26999

35871

Certificate of calibration CERT-NIST


39

M

Spare Parts

Item

Battery door

Knob, CONTRAST

Battery replacement (six required)





Additional printer paper, 1 roll

Battery Holder

Megger Part Number

55-20003

55-20004

35956

35938

35942

36013

36042

26999

EV22410-006

40


Appendix C

Connections and Vector Voltage Diagrams

Table C-1 and C-2 show winding diagrams for standard transformers and nonstandard transformers for power and distribution transformers marked in accordance with the ANSI standard.

To make a measurement on a three-phase power transformer with TTR20 test set, match the vector diagram from the transformer nameplate to the corresponding winding connection diagram from Table C-2. Then connect the

TTR20 test leads to the appropriate transfo rmer winding terminals of phase A.

Put an external jumper, if required. After phase A test is complete, reconnect the test leads to phase B. Put an external jumper, if required. After phase B test is complete, reconnect the test leads to phase C. Put an external jumper, if required. Compare the measured test results to the calculated turns ratios.

NOTE. Three phase transformer may be tested in any order. For example, phase

C, then phase A, and then phase B turns ratio may be tested.

The tables show the windings tested for each of the three phases. The tables also show the relationship between the measured turn ratio and the actual lineto-line voltage ratio. For the ANSI specification, the rated voltage on the high-voltage winding is represented by V

H

; V

X

represents rated voltage on the low-voltage winding.


41

M

T-Type Transformers

T-type transformers represent a special type of three-phase transformers. This transformer may be tested as a single phase transformer.

To make a measurement on a T-type transformer, the jumpers indicated in Table

C-1 should be applied to the appropriate terminals of the T-type transformer. The

TTR20 measured turns ratio should be compared to the calculated turns ratio indicated in Table C-1.

Notes to Table C-1

1. Any connection(s) to g round/case of T-type transformer on H or X side should be removed before testing a transformer.

2. Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result)

Table C-1 ANSI Transformer Winding Phase Relationship

IEC

Vector

Group

Winding Connection

High-Voltage

Winding (H)

Low -Voltage

Winding (X)

External

Jumpers

Phase tested

T-T

30 lag

T-T

0

H

1

X

1

-

H

1

-H

2

X

1

-X

2

H

2

-H

3

X

1

-X

2

B

A

B

A

Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

1

- H

2

H

1

– H

3

X

1

- X

2

X

1

– X

3

H

1

– H

3

H

2

– H

3

X

1

- X

2

X

1

– X

3

T-T

30 lead

H

2

-H

3

X

1

–X

3

B

A H

1

– H

3

H

2

– H

3

X

1

– X

3

X

2

– X

1

Calculated

Turn Ratio

V

H

V

X

V

H

V

X

V

H

•

V

X

V

H

V

X

•

2

3

2

3

V

H

V

X

•

2

3

V

H

V

X

•

2

3


42

Appendix C

Notes to Table C-2

Transformer terminal markings for distribution and power transformers marked in accordance with requirements of American National Standard Institute, Inc

(ANSI) standard C57.12.70 – 1978.

Definition of Symbol Designations

X

0

*

V

H

V

X

H

1

, H

2

, H

3

External terminals on HV transformer winding.

X

1

, X

2

, X

3

External terminals on LV transformer winding.

H

0

External neutral terminal on HV transformer winding.

External neutral terminal on LV transformer winding.

Inaccessible neutral point on HV or LV transformer winding.

Nameplate voltage rating (line-to-line) of HV transformer winding.

Nameplate voltage rating (line-to-line) of LV transformer winding.

A, B, C a, b, c

Winding tested on HV side of transformer.

Winding tested on LV side of transformer.


43

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2

3


Copyright 1999



Megger

Winding Connection

Diag

No.

1

IEC

Vector

Group

1

φ

1ph0

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

1

φ

External

Jumpers



1

φ

1ph6

Dd0

1

φ

A

B

C





Winding Tested

High-

Voltage

Low -

Voltage

Winding

H

1

- H

2

Winding

X

1

- X

2

H

1

- H

2

X

2

- X

1

H

1

- H

3

H

2

- H

1

H

3

- H

2

X

1

- X

3

X

2

- X

1

X

3

- X

2

Measured

Turn Ratio

V

H

V

X

V

H

V

X

V

H

V

X

4 Dd6

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

5 Dyn1 A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

1

- X

0

X

2

- X

0

X

3

- X

0

V

H

•

V

X

3

6 Dyn7

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

0

- X

1

X

0

- X

2

X

0

- X

3

V

H

•

V

X

3

7 YNyn0

A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

1

- X

0

X

2

- X

0

X

3

- X

0

V

H

V

X


44

Appendix C


Copyright 1999



Megger

Winding Connection

Diag

No.

8

IEC

Vector

Group

YNyn6

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers



Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

H

1

2

H

3

- H

0

- H

0

- H

0

X

0

- X

1

X

0

- X

2

X

0

- X

3

Measured

Turn Ratio

V

H

V

X

9 YNd1

A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

1

- X

2

X

2

- X

3

X

3

- X

1

V

X

V

H

•

3

10 YNd7 A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

2

- X

1

X

3

- X

2

X

1

- X

3

V

X

V

H

•

3

11 Dy1

12 Dyn5

13 Dy5

A

B

C

A

B

C



H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

- H

3

H

2

- H

1

H

3

- H

2

H

H

1

2

H

3

- H

3

- H

1

- H

2

X

1

- *

X

2

- *

X

3

- *

V

H

•

3

V

X

X

3

- X

0

X

1

- X

0

X

2

- X

0

V

H

•

V

X

3

A

B

C

H

3

- H

2

H

1

– H

3

H

2

– H

1

H

1

- H

3

H

2

– H

1

H

3

- H

2

X

3

- *

X

1

- *

X

2

- *

V

H

•

V

X

3


45

M


Copyright 1999



Megger

Winding Connection

Diag

No.

14

IEC

Vector

Group

Dy7

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers

H

3

- H

2

H

1

- H

3

H

2

- H

1

Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

H

1

2

H

3

- H

3

- H

1

- H

2

* - X

1

* - X

2

* - X

3

Measured

Turn Ratio

V

H

•

3

V

X

15 Dyn11 A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

0

- X

3

X

0

- X

1

X

0

- X

2

V

H

•

3

V

X

16 Dy11

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

- H

3

H

2

– H

1

H

3

- H

2

* - X

3

* - X

1

* - X

2

V

H

•

V

X

3

17 Dz0

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

1

- X

3

X

2

- X

1

X

3

- X

2

V

H

V

X

18 Dz6

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

19 YNy0

A

B

C

H

2

- H

0

H

3

- H

0

H

1

- H

0

H

1

- H

0

H

2

- H

0

H

3

- H

0

X

1

- *

X

2

- *

X

3

- *

V

H

V

X


46

Appendix C


Copyright 1999



Megger

Winding Connection

Diag

No.

20

IEC

Vector

Group

Yyn0

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers



Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

H

1

2

H

3

- H

3

- H

1

- H

2

X

1

- X

3

X

2

- X

1

X

3

- X

2

Measured

Turn Ratio

V

H

V

X

21 Yy0

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

1

- X

3

X

2

- X

1

X

3

- X

2

V

H

V

X

22 YNy6

A

B

C

H

2

- H

0

H

3

- H

0

H

1

- H

0

H

1

- H

0

H

2

- H

0

H

3

- H

0

* - X

1

* - X

2

* - X

3

V

H

V

X

23 Yyn6

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

24 Yy6

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

25 Yzn1

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

1

- X

0

X

2

- X

0

X

3

- X

0

V

H

•

3

V

X


47

M


Copyright 1999



Megger

Winding Connection

Diag

No.

26

IEC

Vector

Group

Yz1

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers

H

3

- H

2

H

1

- H

3

H

2

- H

1

Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

1

H

H

3

2

-(H

3

(H

1

-(H

2

+H

2

+H

3

+H

1

)

)

)

X

1

- X

2

X

2

- X

3

X

3

- X

1

Measured

Turn Ratio

V

H

V

X

•

2

3

27 Yzn5

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

3

- X

0

X

1

- X

0

X

2

- X

0

V

H

•

3

V

X

28 Yz5

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

•

2

3

29 Yzn7

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

0

- X

1

X

0

- X

2

X

0

- X

3

V

H

•

3

V

X

30 Yz7

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

2

- X

1

X

3

- X

2

X

1

- X

3

V

H

V

X

•

2

3

31 Yzn11

A

B

C



H

1

- H

3

H

2

- H

1

H

3

- H

2

X

0

- X

3

X

0

- X

1

X

0

- X

2

V

H

•

3

V

X


48

Appendix C


Copyright 1999



Megger

Winding Connection

Diag

No.

32

IEC

Vector

Group

Yz11

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers

H

3

- H

2

H

1

- H

3

H

2

- H

1

Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

1

H

H

3

2

-(H

3

-(H

-(H

2

1

+H

2

+H

+H

1

3

)

)

)

X

1

- X

3

X

2

- X

1

X

3

- X

2

Measured

Turn Ratio

V

H

V

X

•

2

3

33 ZNy5

A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

X

V

H

•

3

34 Zy5

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

•

2

3

35 ZNy11

A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

1

- X

3

X

2

- X

1

X

3

- X

2

V

X

V

H

•

3

36 Zy11

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

1

- X

3

X

2

- X

1

X

3

- X

2

V

H

V

X

•

2

3

37 Yd1

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

1

- X

2

X

2

- X

3

X

3

- X

1

V

H •

V

X

2

3


49

M


Copyright 1999



Megger

Winding Connection

Diag

No.

38

IEC

Vector

Group

YNd5

High-Voltage

Winding

Low -Voltage

Winding

Phase

Tested

A

B

C

External

Jumpers



Winding Tested

High-

Voltage

Winding

Low -

Voltage

Winding

H

H

1

2

H

3

- H

0

- H

0

- H

0

X

3

- X

1

X

1

- X

2

X

2

- X

3

Measured

Turn Ratio

V

X

V

H

•

3

39 Yd5

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

3

- X

1

X

1

- X

2

X

2

- X

3

V

H

V

X

•

2

3

40 Yd7

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

2

- X

1

X

3

- X

2

X

1

- X

3

V

H

V

X

•

2

3

41 YNd11

A

B

C



H

1

- H

0

H

2

- H

0

H

3

- H

0

X

1

- X

3

X

2

– X

1

X

3

– X

2

V

X

V

H

•

3

42 Yd11

A

B

C

H

3

- H

2

H

1

- H

3

H

2

- H

1

H

1

-(H

3

+H

2

)

H

2

-(H

1

+H

3

)

H

3

-(H

2

+H

1

)

X

1

- X

3

X

2

- X

1

X

3

- X

2

V

H

V

X

•

2

3


50

No results