DWR-10-User Manual Octuserequip.com/files/specs/5067/DWR-10-User Manual_Rev2.pdfDC resistance of windings is measured by passing DC current through the unknown resistance, and measuring

User Manual Model DWR-10 Reporter

Winding Resistance Test Set

ADWEL International

Limited

Copyright © 2004 ADWEL International Ltd.

Copyright in this document is owned by ADWEL International Limited except for information supplied by other parties.

No reproduction of the whole or any part is to be made without the authority of ADWEL International Limited

DWR-10 Reporter™ is a trademark of ADWEL International Ltd.

Head Office:

ADWEL International Ltd. 50 Ironside Crescent, Unit 6 Toronto, ON, Canada M1X 1G4 Tel: 416-321-1988 Toll-free: 800-463-9371 (Canada/U.S.) Fax: 416-321-1991 Email: [email protected] Web: www.adwel.com European Office:

ADWEL International Ltd. Park House, Greenhill Crescent Watford Business Park Watford, Herts, WD18 8PH United Kingdom Tel: 44-(0) 1923-254433 Fax: 44-(0) 1923-218278 E-mail: [email protected]

Version 02, September 2004

Table of Contents

September 2004 Page iii

Table of Contents

Safety Warnings............................................................vii Safety Symbols...................................................vii

High Voltage Safety Precautions ......................viii Built-in Safety Precautions..................................ix Power Source.......................................................ix

Chapter 1, Introduction...................................................1 Application............................................................1

Features ................................................................2 Options and Accessories .....................................3

Standard Accessories ............................................. 3 Test Leads .................................................... 3

Optional Rigid Carrying Case ................................ 4 Custom Lead Lengths ............................................ 4 Optional 'T' Version............................................... 4

Operating Principles.............................................4

Chapter 2, Getting to Know the DWR-10 .......................7 Main Controls........................................................8

Navigation Knob ................................................... 8 Standard Buttons ................................................... 8 Switches and Connections...................................... 9 Buttons for 'T' Version......................................... 10

LCD Screen .........................................................10

Main Status Panel ...............................................12 Manual Mode ...................................................... 12 Timed Mode........................................................ 13

Table of Contents

Page iv September 2004

Measuring Window ............................................ 14 Channel Board..................................................... 15

Protection Circuit State............................... 15 Measurement Display ................................. 16

Current/Dump Status Bar..................................... 17 Toolbars ............................................................. 19

Default Toolbar ................................................... 20 Print Toolbar ....................................................... 21 Keyboard Toolbar................................................ 21

Menu List............................................................ 23 Menu Structure.................................................... 24 Unit Definition Menu Option ............................... 24 Mode Menu Option ............................................. 26 Print Menu Option............................................... 26 Time Interval Menu Option ................................. 26 Files Menu Option............................................... 27 System Menu Option ........................................... 28

Prompt Messages .............................................. 30 Regular Messages................................................ 30 Warning Messages............................................... 30 Error Messages.................................................... 31

Chapter 3, Measuring with the DWR-10....................... 33 Preparation......................................................... 33

Locating the DWR-10.......................................... 33 Setting Input Voltage........................................... 33 Turning On the DWR-10 ..................................... 34 Setting Outputs and Ranges ................................. 34

List of Current Outputs and Ranges ............ 35 Connecting to Transformer .................................. 35

Testing One or Two Windings .................... 36 Series Connection Table ............................. 37

Changing Tap and Winding Names...................... 38 Test Modes......................................................... 39

Testing in Manual Mode...................................... 39

Table of Contents

September 2004 Page v

Testing Without Saving .............................. 40 Testing and Saving ..................................... 40 Stability of Readings................................... 41

Testing in Timed Mode........................................ 42 Changing Windings and Testing Taps...............45

Changing Winding Connections........................... 45 Testing Tap with On-load Tap Changer................ 45 Testing Tap with De-energized Tap Changer........ 46

Chapter 4, File Management.........................................47

File Viewer...........................................................47 Quick Start .......................................................... 47 Open File Viewer................................................. 48 File Information................................................... 49 Delete One File.................................................... 50 Delete All Files.................................................... 51

Transferring Files to a PC...................................51 Transfer Procedure............................................... 51 DWR File Transfer Window ................................ 53 File Information................................................... 53

Printed Reports...................................................55

Appendix A, Technical Specifications.........................57

Appendix B, Connection Diagrams .............................59 Winding Diagrams ..............................................59

Single Phase, One Winding.................................. 59 Single Phase, Two Winding Test.......................... 60 Three Phase, Two Windings, Accessible Neutral.. 61 Three Phase, One Winding, Non-Accessible Neutral ................. 62 Delta Delta, Two Windings.................................. 63

ANSI Vector Diagrams & Connection Matrices .64

September 2004 Page vii

Safety Warnings

The DWR-10 can produce lethal voltages. This can occur in any high-voltage equipment when there is an interruption in current.

Comply with all equipment grounding instructions to avoid dangerous electrical shocks.

Only properly trained personnel should use the DWR-10. Safety is the responsibility of the user.

1. Read all safety and operating instructions before operating the equipment.

2. Retain this User Manual for future reference.

3. Heed all safety warnings on the equipment and in the manual.

4. Follow all operating instructions.

Safety Symbols In this manual, the safety symbol with an exclamation point alerts you to operating and maintenance instructions that you need to follow to protect your safety.

Safety Warnings

Page viii September 2004

On the test set, the symbol with a "lightning flash arrow" alerts you to the presence of an uninsulated voltage with enough magnitude to produce an electric shock.

Whenever there is current in the load, a flashing warning logo will appear, along with a warning message and an audible warning tone.

High Voltage Safety Precautions The DWR-10 test set and any transformer to which it is connected are possible sources of high-voltage electrical energy.

Anyone using the test set must take all practical safety precautions to prevent contact with energized parts of the equipment and related circuits.

• Never connect the test set to energized equipment.

• Do not use the test set in an explosive atmosphere.

• Stand clear of all parts of the high-voltage circuit, including all connections, unless the test set is de-energized and all parts of the test circuit are grounded.

• Keep other people away from test activities with suitable barricades or warnings.

• Treat all terminals of high-voltage power equipment as potential electric shock hazards. Voltages may be induced at these terminals because of proximity to energized high-voltage lines or equipment.

• Always disconnect test leads from the power equipment before disconnecting them at the test set. The ground connection must be the first made and the last removed.

Safety Warnings

September 2004 Page ix

• Wearing rubber glovers is recommended as a routine safety precaution whenever working with the test set.

• Maintenance must be performed by qualified personnel who are familiar with the construction and operation of the test set and the hazards involved.

High-voltage discharges and strong electric or magnetic fields may interfere with heart pacemakers. If you have a pacemaker, obtain medical advice on the possible risks before getting close to the energized test set.

Built-in Safety Precautions To prevent operator injury or equipment damage, the current output is protected against interruptions that may occur during testing. The test set's two potential channels are equipped with bi-polar over-voltage crowbars, which provide a low resistance path for inductive current if the excitation leads are disconnected while the test set is energized.

Power Source The DWR-10 operates from a single-phase power source. It requires a two-pole, three terminal, live, neutral, and ground type connector.

The voltage to ground from the live pole of the power source must not exceed the maximum rated operating voltage—the unit is equipped with a voltage selector power input module. Ensure the voltage is properly selected before use. The neutral pole must be at ground potential.

Safety Warnings

Page x September 2004

Before connecting to the power source, determine that the instrument rating matches the voltage of the power source and has a suitable two-pole, three-terminal grounding type connector.

Before plugging in the three-wire power cord, make sure the receptacle is properly wired and has a ground contact. Do not bypass the grounding connection. Any interruption of the grounding connection can create an electric shock hazard.

September 2004 Page 1

Introduction

The Digital Winding Resistance Reporter, Model DWR-10, provides accurate, high-resolution measurement of transformer winding resistance.

Application Transformers have many internal connections that can become loose as a result of poor quality, vibration from years of service, or from through faults.

The DWR-10 provides valuable information about the condition of the transformer windings by measuring the DC resistance in the windings. The winding resistance test also checks for correct transformer connections and changes to the tap ratio.

The test is performed by injecting DC current through the resistance and measuring the resulting voltage drop.

Test results are an important tool in preventing unplanned outages and premature failures. A winding resistance test should be applied as part of a preventive maintenance program or as a routine test in a manufacturing process.

The winding resistance test is particularly valuable for transformers with on-load tap changers, because they have hundreds of bolted connections and moving contacts.

Chapter

1

Chapter 1 — Introduction

Page 2 September 2004

Features • Ability to measure and save more than 10,000 high-

resolution test results, including tap and winding details, and transformer nameplate data

• High resolution (4½ digits) and high accuracy (0.25%) for precise measurements

• Connects directly to a PC for transferring files to other applications, using RS-232 and USB ports

• Data easily imported to Microsoft Excel® and Microsoft Word® for quick generation of graphs and other user-defined calculations

• Large, color LCD screen, 120 mm x 90 mm (4.75" x 3.5"), for entering equipment details and presenting results, in various languages

• Bright LCD screen for easy viewing on a sunny day

• Graphical user interface (GUI) uses familiar pull-down menus and toolbars

• Multi-language operation

• Easy to use file manager, with files named according to the transformer serial number

• 40-character wide built-in printer, which uses standard 3-inch wide thermal paper, and produces easy-to-read rows and columns

• Easy report generation using Microsoft Excel®

• Screen navigation via a cursor, which is controlled by a turn-and-press knob

• Waterproof, rugged, and reliable



• Sigma-delta A/D converters and notch filters on input channels to eliminate effects of substation noise

• Robust power supply for fast testing of large power transformers

• Remote tap-changer operation

Options and Accessories

Standard Accessories

The DWR-10 comes with these standard accessories:

• test leads, 10 m in length (30 ft) • User Manual (this document) • accessories case • training video • three rolls of thermal paper for the printer • calibration certificate

Test Leads

Each DWR-10 comes with test leads for testing a single winding:

• a positive pair consisting of a positive current and a positive potential lead

• a negative pair consisting of a negative current and a negative potential lead

To test two windings in series, additional cables areprovided:

• a jumper cable • a single positive potential lead • a single negative potential lead



Optional Rigid Carrying Case

To carry or transport the DWR-10 safely, the instrument is also available in an injection-molded case with rigid reinforced walls.

An extendable handle and 3-inch wheels make maneuvering easy.

Layered foam filling protects the instrument from the impacts of everyday travel. The silicone o-ring seal protects the DWR-10 from salt air, water, sand, and dust.

Custom Lead Lengths

Test leads are also available in longer lengths of 12 m (40 ft) or 15 m (50 ft).

Optional 'T' Version

The DWR-10 is available in an optional 'T' version. In this model, measurements can be taken automatically at set intervals, and the date and time of the winding resistance measurement is also recorded.

The interval measurements are stored in a single file, as opposed to multiple files for the standard DWR-10 model.

Operating Principles DC resistance of windings is measured by passing DC current through the unknown resistance, and measuring the resulting voltage drop The DWR-10 calculates the resistance by the formula R=E/I

Measuring small DC resistance in a highly inductive environment can be a challenging task. The voltage across an inductor is defined by the formula V = L di/dt. Some



power transformers have an inductance over 1000 henrys. Therefore, minute changes in current will result in undesirable voltage swings that can make it impossible to measure the DC resistance of the transformer windings.

The ADWEL DWR-10 addresses this challenge in several ways, so that the instrument can achieve stable resistance readings on the largest transformers in record time.

• The DWR-10 uses a powerful, highly regulated, and filtered constant current source to drive current through the windings.

• It uses a 10 A (30 V) source, which is enough to drive the core quickly into saturation where small changes in current have no effect on the measured resistance.

• By connecting the primary and secondary windings in series, the speed of saturation and stability of the readings is increased because there are more amp-turns contributing to the flux in the core. The resistance measurement of both windings is made at the same time on channels A and B.

The instrument works best when the transformer core has been driven into saturation by the DC current. In this condition, the readings stabilize quickly and are not affected by small changes in current.


Getting to Know the DWR-10

This chapter describes the various features, tools, and screens of the DWR-10, and how to navigate the system.

Chapter

2

Chapter 2 — Getting to Know the DWR-10


Main Controls

Navigation Knob

The navigation knob is located at the bottom center of the DWR-10 panel. To operate the knob:

• Turn clockwise to move to the right.

• Turn counter-clockwise to move to the left.

• When the cursor passes over a button or field, the button or field is highlighted. Press the knob to select the button or enter data in the field.

• The highlight will automatically pass from field to field as you turn the knob (i.e., clockwise scrolls down and counter-clockwise scrolls up).

• Press and hold the knob for one second to save and exit a field.

Standard Buttons

Various buttons control the display functions. They are located around the main screen on the DWR-10 panel.

Item Description Back Press to cancel or return to the previous menu

level, and ultimately back to the default toolbar. Tap Changer

Press to remotely change the tap on the transformer winding.

Menu Press to open the menu list.



Item Description Tap/Winding Press to open the Tap, Winding selection frame

and define their names. Test/Dump Press to start or stop output current.

Switches and Connections

Power to the system is supplied through a standard outlet and detachable power cord at the top left of the DWR-10 panel. The power entry module along the top of the panel includes the power switch, fuses, voltage selector, voltage indicator, and connections.

Item Description Power plug To connect the power supply cord to a wall outlet

(top left of panel). Main power switch

Switches the DWR-10 on and off (switch at top left of panel).

Voltage selector and indicator

Part of the main power switch. Use a screwdriver to switch the voltage to either 115 V or 230 V.

A Channel A voltage connection (top center of panel). Use insulated banana plugs.

B Channel B voltage connection (top center of panel). Use insulated banana plugs.

Current contacts

Screw-secured current injection contacts, similar to binding posts (to the left of the A and B voltage connections). Position the connector to avoid interference with the wings of the binding posts.

Tap To connect the tap changer switch to the tap motor of the transformer (top center of panel). Use insulated banana plugs.

Metal ground binding post

A non-insulated post to ground the DWR-10 to the system power grid (to the right of the power switch).



Item Description Emergency button

Cuts off the DC current output (not the instrument power supply). It is the large red mushroom button located at the bottom center of the DWR-10 panel. When you press this button, data is saved with the letter 'N' at the end of the filename, to indicate that the measurement file was not closed properly.

RS-232 port (DB9)

To transfer the readings to a PC (to the left of the emergency button).

USB port To transfer the readings to a PC (to the left of the emergency button).

Buttons for 'T' Version

Item Description Clock On/Off Press to start or stop the clock and enable it to

count Total Time. When in Timed mode, you can inject current and dump data without stopping the timer.

Auto On/Off Press to start or stop the timed interval measurement as per the specified interval. When you start the measurements, actual resistance values will be saved, including the Total Time, and the Next Measurement will count down. You can temporarily stop the automatic readings to change windings or taps by pressing the Test/Dump button. Then resume automatic readings.

LCD Screen The LCD screen is divided into four parts:

• main status panel (on top) • measuring window (center)



• current/dumping status panel (under the measuring window)

• toolbars (lower screen)

Message line for commands and warnings. Protection indicator shows when current dumping

is being done through that channel. Highlight and press knob to save measured values. Toolbars: highlight and press buttons to set test

current, resistance range, or auto-range; also to save and end, or to scroll through results. (A print toolbar and keyboard toolbar are also available on some screens.)

Date and time always displayed. Reading Stability indicator shows green when

measured reading becomes stable. Bright, easy-to-read 4½ digit display of measured

resistance.



Indicates actual test current.

Main Status Panel For detailed information on how to use Manual mode and Timed mode, see page 39.

Manual Mode

In Manual mode, the main status panel indicates the following information:

Item Description Serial number

If a serial number for the tested transformer was entered in the Unit Definition window (the main data entry screen; see page 24), it will display in the upper left corner of the main status panel. Otherwise, this space will be blank.

Date Located to the right of the serial number. Time Located just under the Date indicator.

(Note: Set the date and time in the date/time window of the System menu.)

Command prompt

Located just under the serial number and date/time indicators, this provides either instructions (black) or warnings (red).



For a complete list of possible messages that can be displayed in the command prompt, see page 30.

Timed Mode

When the DWR-10 is set to Timed mode, the main status panel displays differently. The three fields on the right display only in Timed mode.

Item Description Total Time Indicates the total testing time since the beginning

of the session. Interval Time Displays the chosen interval between two saved

measurements, in seconds. During the interval time, the test set records data automatically.

Next meas. Indicates the remaining time before the next measurement to be saved. This is a countdown loop that continues unless the timed interval is interrupted. It displays only if the Auto on/off button has been pressed to turn on timed interval measuring. When in manual mode (that is, the clock is running but timed interval saving is off), only the Total Time and Interval Time display.



Measuring Window

The measuring window is the center part of the display. Two channel boards provide all necessary information about each measuring channel—A and B, along with corresponding data.

Between the channel boards are the Tap and Winding tags, which display the names of the tap and winding. They can be modified here.

Above the Save button is the measuring position information (e.g., 03/02). The left digit tells you where the displayed measurement is located in the measuring list when you scroll through the values. The right digit indicates the total number of readings recorded for that measurement—either manually, or manually plus automatically (timed).

The position display updates automatically each time a new measurement is recorded in a timed interval sequence, and each time you press the Save button in Manual mode.



Channel Board

Each channel board (A and B) displays measurement data for that channel.

Protection Circuit State

Item Description Protection Indicates when current dumping is being done

through the crowbar of that channel. The LED indicator is gray when the crowbar is open (while measuring or dumping) and turns to red when the crowbar closes, dumping the transformer energy through the voltage channel instead. A warning message appears: “CROWBAR PROTECTION ACTIVATED.” When the current drops, the crowbar circuit resets itself and all warning messages disappear.

Reading Stability

Indicates if the voltage reading (and displayed resistance reading) has stabilized. The LED indicator is gray when the DWR-10 is idle, when it is dumping current, or when measuring has begun but is not yet stabilized. It turns yellow when approaching stability (1% or less variation in the value for ten consecutive readings). It turns green once the nominal current value is reached and the resistance measurement is almost the same each time (within a 0.25% tolerance for ten readings in a row).



Measurement Display

The measurement display shows the actual resistance value and the unit of measurement. If no measurements have been taken yet, a series of dashes will display.

If one of the channels is not used, it can be turned OFF using the range switch for that channel.

The channel boards display information about the tap and winding, as well as readings for recorded measurements. The number of readings is displayed above the Save button between the channel boards (right digit). In the screen example above, there are two readings for measurement number 3.



Current/Dump Status Bar

The status bar in the above screen example indicates that current has built up in the transformer, to 100% of nominal value.

The status bar examples above shows the current building up inside the transformer winding. To the right of the bar graph, the current build-up is shown as a percentage and in amps.

When it reaches 100%, the current has stabilized to the nominal value. The amperage shown will be the same as the nominal current value on the Current button (left side of the default toolbar). The Reading Stability indicator turns green.

When the test is finished, press the Test/Dump button. The Current Status tag changes to Dump Status and the bar graph turns red. The percentage and amperage values go to zero.



A yellow warning indicator on the left of the status bar appears when the current injection begins, and remains until dumping has ended. Do not disconnect any leads during this time.

A warning prompt also appears on the main status panel (red background), warning you not to disconnect the leads while testing or dumping.



Toolbars Toolbars can be displayed by pressing a button on the screen, by selecting an option, by pressing the Back button, or by pressing a button on another toolbar. There are three toolbars:

• Default toolbar • Print toolbar • Keyboard toolbar

Each toolbar has several control buttons. To activate a button, turn the knob to move the cursor over it and highlight it, then press the knob.

There are three types of control buttons:

Setting buttons — Examples: Current and Range buttons. When pressed, the button is activated, allowing you to adjust a setting by looping through a finite number of possible values as you turn the knob. Press to select a value and de-activate the button. If you press the Back button while a setting button is activated, you will de-activate the button but leave the original setting value unchanged.

Function buttons — Examples: Print and Feed buttons These buttons perform a simple command and act as momentary pushbuttons (that is, you do not have to re-press to de-activate, as with Setting buttons).

Action buttons — Example: Scroll Readings buttons. These buttons act like an on/off switch. When pressed, the button background turns light blue and remains activated until you press it again or press the Back button. Use action buttons to perform a simple action (not setting a value).



Default Toolbar

The default toolbar is displayed on start-up and has five control buttons. When another toolbar is displayed, you can press the Back button to return to the default toolbar.

Item Description Current This setting button can be set to one of four

possible values as you turn the knob: 10A, 1A, 0.1A, and 0.01A. The default value is 10A. The Current button is locked during measuring (current injection), but is available at all other times. When you change the current setting, the A and B channel ranges are updated—they stay the same if their actual setting is available for the new current setting. If not, they automatically switch to the closest, most precise range value available.

A and B Range buttons

These setting buttons can be set to one of six values as you turn the knob: four ranges values, AUTO, and OFF. Available range values depend on the nominal current setting (displayed on the Current button). If you set the range to AUTO, the title blinks, displaying A Range and A Auto alternately, indicating that the actual setting is Auto range. See the example below.

Scroll Readings

Press this action button to scroll through the readings taken since the beginning of the test. It shows one reading at a time. The corresponding tap and winding names are also displayed. (You can see where you are by looking at the numeric list position above the Save button.)



Item Description End & Record Session

Press this function button to save the entire measuring file. This button closes a reading file properly. It is highlighted by default when you first activate the default toolbar. When you press this button, a warning window displays: “Save in Progress, Please Wait.”

Print Toolbar

Display the print toolbar by choosing the Print option in the menu list.

Item Description Print Press to print the reading report. Feed Press to make thermal paper come out of the

printer in increments of 1mm. Press and hold down the knob to make the paper feed continuously.

Reset Press to make the printer stop and clear its spooler. This has no effect on readings that are in memory. The purpose of this button is to allow you to stop printing in error, or if there is a paper jam or other printer problem.

See page 55 for information about test reports and print-outs.

Keyboard Toolbar

You can display the keyboard toolbar in several ways:

• Display the Unit Definition window (select from the menu list).



• Select a tap or winding field, or press the Tap/Winding button.

• Press the Save button when the serial number field is still blank.

To enter or modify data using the keyboard toolbar:

1. Turn and press the knob to select a field on the screen. This action clears the field of any pre-existing data and opens the keyboard toolbar. The End button on the keyboard also becomes active.

2. Use the knob to highlight individual letters and numbers on the keyboard.

• Turn the knob clockwise to travel from A to End on the keyboard, and counter-clockwise to travel in reverse from End to A.

• When the knob highlight reaches the end of the keyboard (or the beginning), it automatically cycles back to the A (or End) button.

3. Press on a highlighted letter or number to enter it in the activated field.

• Press the CAP button to enter all text in capital letters.

• Enter a space by pressing the Space button. • If you make a mistake while entering data in a

field, press Backspace ( ), select the character to delete, and press.

• Delete an entire field by pressing Clear Field.



4. Continue highlighting and pressing letters and numbers till the field is complete. A maximum of twenty (20) characters can be entered per field.

5. When the field is complete, press the End button on the keyboard. Or, press and hold the knob for one second. Both actions save the new data in the field.

6. Repeat the above steps for other fields.

7. Press the Back button to close the keyboard toolbar and return to the default standard toolbar.

Menu List Display the main menu by pressing the Menu button on the DWR-10. A list of options appears. If the option has an arrow beside it, further options are available on a sub-menu list. Each option and sub-option is described below.



Menu Structure

Unit Definition Mode

Manual Timed

Print Time Interval Files

Open File Viewer Delete One File Delete All Files

System Date/Time Sound

High Medium Low Off

Communication Port USB RS-232

Language About DWR

Unit Definition Menu Option

Select this option to display the Unit Definition window. This window also displays when you try to save a measurement but the serial number has not yet been entered.

The Unit Definition window defines the information to be saved with a file. When it displays for the first time, it is empty.

When data has been entered previously, the window displays the last entry by highlighting the background in the upper text field.



Enter data in the Unit Definition window using the keyboard toolbar, which displays automatically when the window opens.

Item Description

Serial number

Enter the serial number of the transformer.

Company Enter your company name. Station Enter a substation number. Designation Enter a transformer number. Manufacturer Enter the name of the transformer manufacturer. Operator Enter your name. Notes Enter any relevant information about the

transformer or the measurement. Temperature If desired, enter a temperature value. This can be

the ambient temperature around the transformer, or the temperature of the transformer itself.



Mode Menu Option

The Mode option on the menu list allows you to select the measuring mode for the DWR-10, either manual or timed. Manual mode is the default value.

For detailed information on these modes, see page 39.

Print Menu Option

Select the Print option to display the Print toolbar. Then press the Print button on the toolbar to print the measurement data for the selected tap or winding.

Time Interval Menu Option

Select the Time Interval option to change the time interval setting after it has been entered in Timed mode. The Time Interval setting window appears.

Change the number of seconds by turning the knob and pressing OK when the correct number is highlighted. The default value is 15 seconds. It can be set from 5 seconds to 100 seconds.



Files Menu Option

The Files option allows you to open the File Viewer to open or delete a single file, or delete all files.

For detailed information on the File Viewer, see page 47.



System Menu Option

Select the System menu option to adjust various settings that do not influence the measuring. There are five sub-menu options.

Item Description

Date/Time Displays a window where you can update the date and time (turn and press the knob). Format is yy/mmm./dd and hh:mm.

Sound Select the intensity of the audio signal, or turn it

off.



Item Description Communication port

Select the serial communication port for downloading files to a PC.

Language Select the language. The default is English.

Selecting another language will automatically convert all screen and field information to that language.

About Displays information about the DWR-10, including

software versions, serial number, and ADWEL contact information.



Prompt Messages Various messages may display in the command prompt line, as described below.

Regular Messages

Regular messages provide information on the instrument status, or suggest an action to take. They display in white letters on a black background.

Press Test Dump to Start Measuring — displays on startup and whenever the instrument is idle and no command is active.

VIEW FILE, Press Back to Normal Mode — displays in the File Viewer window, indicating that you can view a measurement file, then press the Back button to return to the main screen.

Warning Messages

Warning messages are always displayed in white letters on a red background. They indicate a possibility of danger for the operator or for the test set.

TESTING do not disconnect LEADS — displays when current is being injected and no other command is active.

DUMPING do not disconnect LEADS — displays when dumping current, with no other command active.

EMERGENCY BUTTON ACTIVATED — displays when the emergency button has been pressed.

CURRENT DISCONNECTED!!! — displays when the current loop has been broken.



CROWBAR PROTECTION ACTIVATED — displays when the Potential Input Protection circuit is activated. The Protection indicator on each channel board will also turn red.

Error Messages

Error messages may sometimes appear in a pop-up window (not the command prompt line). They indicate problems with the DWR-10.

Error messages comes with an error number, which can be helpful for the service person to diagnose and repair the problem. Record the text of the error message and the error number and contact ADWEL International for additional help and information.


Measuring with the DWR-10

Preparation

Locating the DWR-10

Find a convenient location for the DWR-10.

• It should be within 15 to 20 feet of all transformer connections and tap changer controls.

• Horizontal or vertical mounting will allow easy access to the front panel for reading and adjusting.

• Be sure not to block the fan intake on the rear side, or the fan outlet on the front panel.

Setting Input Voltage

The power entry module at the top of the DWR-10 panel includes the power switch, fuses, voltage selector, and voltage indicator.

Chapter

3

Chapter 3 — Measuring with the DWR-10


Before connecting the DWR-10, ensure you set it to the correct AC voltage as used in your country. Use a screwdriver to switch the voltage.

• 115 V — for ranges between 90 V and 132 V • 230 V — for ranges from 198 V to 256 V

Turning On the DWR-10

Turn on the power switch. A splash window appears with the ADWEL logo and the DWR logo. It also displays the code versions of the hardware.

Each time the instrument starts up, it goes through a memory defragmentation process that compacts space for new recordings.

Setting Outputs and Ranges

By default the instrument will be set for 10 amp output, with the measuring scales in Auto range. (10 amps is suitable for any resistance up to 2 ohms).



Other current outputs can be set to test resistance up to 2000 ohms. Refer to the following table for a complete list of current outputs and measuring ranges. Always use the highest current possible, because this will provide the fastest testing.

Use the default toolbar to change the current and ranges:

• Press the Back button to display the default toolbar.

• Use the knob to highlight and press the function you want to change (Current, Range A, Range B, etc.)

• If you are using only one channel, use the Range button to set unused channels to the off position.

• Press the Back button to return to the main screen.

List of Current Outputs and Ranges

Each of the DWR-10's four current ranges can be set to four resistance ranges, as well as Auto or Off.

Current Auto Range Range 1 Range 2 Range 3 Range 4 Channel

Off

10 [A] X 0.1uΩ–1.9999mΩ

1uΩ-19.999mΩ

10uΩ-199.99mΩ

0.1mΩ-1.9999Ω

X

1 [A] X 1uΩ-19.999mΩ

10uΩ-199.99mΩ

0.1mΩ-1.9999Ω

1mΩ-19.999Ω

X

0.1 [A] X 10uΩ-199.99mΩ

0.1mΩ-1.9999Ω

1mΩ-19.999Ω

10mΩ-199.99Ω

X

0.01 [A] X 0.1mΩ-1.9999Ω

1mΩ-19.999Ω

10mΩ-199.99Ω

0.1Ω-1999.9Ω

X

Connecting to Transformer

Ensure that the transformer to be tested is isolated and de-energized prior to testing.



If the substation is energized, choose a location that is on the de-energized side of the transformer to reduce effects on induction on the test cables and the test set. The test set can tolerate up to 40 volts p-p (peak to peak) between positive and negative terminals, and no more than 50 V from any terminal to ground.

Testing One or Two Windings

Transformers may be tested one winding at a time or two windings at a time, since the DWR-10 has two channels. Two-winding testing is recommended when testing a low-voltage winding on a large capacity transformer (i.e., over 100 MVA).

By connecting the primary and secondary windings in series, the speed of saturation and stability of the readings is increased because there are more amp-turns contributing to the flux in the core. The resistance measurement of both windings is made at the same time on channels A and B.

The polarity of the windings to be connected in series must be considered—the amp-turn effect must be additive, otherwise, there is no advantage to the series connection.

If the transformer is a single-phase unit with terminals marked as H1, H2, X1, and X2, connect as follows:

• Connect the jumper between H2 and X1 (rule of thumb is to connect the jumper between opposite polarities).

• Connect the positive current to H1.

• Connect the negative current to X2.

• Ground one of the points for safety reasons.

This concept can also be applied to three-phase transformers. The table below gives a few examples for



common vector groups. Other connections may be configured by connecting the windings as implied by the connection diagrams in Appendix B.

In a four-terminal connection, the current and potential leads must not touch each other, and the potential connections must be electrically within the current lead connections.

Series Connection Table

Current connections Voltage connections

Type Test + Current

– Current Jumper CH-A CH-B

1 H1 X2 H2-X0 H1-H2 X0-X2 2 H2 X3 H3-X0 H2-H3 X0-X3

Delta/ Wye Dyn1 5 3 H3 X1 H1-X0 H3-H1 X0-X1


Delta/ wye Dyn11 15 3 H3 X0 H1-X3 H3-H1 X3-X0


Wye/ wye YNyn0 7 3 H3 X0 H0-X3 H3-H0 X3-X0


Wye/ delta YNd1 9 3 H3 X1 H0-X3 H3-H0 X3-X1



Changing Tap and Winding Names

Taps and windings need to be designated with labels in DWR-10 before measurements can be saved. Editing of tap and winding names can be done at any time.

1. Press the Tap/Winding button. The A-channel board displays, along with the keyboard toolbar.

2. Enter a tap name, using a maximum of three alphanumeric digits. (In the example above, the tap name is '1.' If no tap name is entered, the field displays with three dashes.)

3. To save, press the End button, or press and hold the knob for one second. The cursor highlight will move to the first winding indicator field.

Note: To skip a field, turn the knob to highlight the next field.

4. Enter the first winding name (H1 in the screen example above) and press End.

5. Enter the second winding name (H2 in the screen example above) and press End. The B-channel board displays.



6. Repeat the above steps for the B-channel.

7. Press the Back button to exit.

Test Modes There are two modes of operation: Manual and Timed.

In Manual mode, you can manually take and record measurements one at a time. There are two manual methods:

• Testing without saving — Perform a fast test without saving any results or data.

• Testing and saving — Save all measured results, tap and winding details, and details about the transformer and its location. You can also produce reports that include all saved data.

In Timed mode, measurements can be taken automatically at set intervals (or manually), and the date and time of the winding resistance measurement is also recorded. Measurements are saved in a single file, as opposed to multiple files for Manual mode. The Timed mode is an optional feature that only comes with the 'T' version of the DWR-10. It is normally only used by transformer manufacturers who must record time data at the end of a heat run to calculate hot resistance.

Testing in Manual Mode

To test in Manual mode:

1. Decide if you want to test and save the results to a file in the memory of the DWR-10, or if you want to test without saving.



2. Decide if you want to test one winding at a time, or two windings in series. (To test two in series, see the instructions above.)

3. Connect the test leads to the transformer.

4. Select Manual mode from the menu list.

Testing Without Saving Use this method if you want to test without saving results and data.

1. Press the Test/Dump button to start the current injection.

2. Press the Test/Dump button again when you are finished. The current indicator will turn red indicating the current is discharging.

3. Do not disconnect the test leads until the reading becomes zero.

Testing and Saving

Use this method if you want to save results and transformer data to a file for future printing or report production.

1. Press the Menu button and open the Unit Definition window.

2. Enter the serial number of the transformer.

3. Enter other data as required in the Unit Definition window (optional).

4. Press the Back button.

5. If required, press the Tap/Winding button to enter tap and winding information.



6. Press the Test/Dump button to apply current and start the test. (See Stability of Readings, below).

7. When the reading is stable, highlight the Save icon and press the knob to save the readings. The displayed measurement results will be saved for both channels. (Each time you click on Save, a new reading is saved into the file.)

If you have not yet entered a serial number for the transformer, the Unit Definition window will display when you press the Save button. This is because data cannot be saved without the serial number, which becomes the filename.

1. Enter the serial number.

2. Enter other data as required in the Unit Definition window (optional).

3. Press the End & Record Session button to save the manual file properly.

If desired, you can conduct more tests on the transformer. See Taps and Windings on page 45.

Note: At least one measurement must be saved (automatically or using the Save function); otherwise, the End & Record Session button cannot save a file.

If you terminate the test by turning off the main power switch, the file will be saved with the letter N at the end of the filename, to indicate that the test was ended improperly.

Stability of Readings

The DWR-10 performs a winding resistance test when you press the Test/Dump button. This starts to inject current into the windings, which can take up to a minute for very large transformers. The DWR-10 then takes a measurement at a fixed interval of one second.



After the current has stabilized, wait for the resistance readings to stabilize. Observe the stability indicators on the screen.

• When readings begin or if they remain unstable, the indicator is gray.

• When 10 consecutive readings have stabilized between a 1% and 0.25% rate of change, the indicator turns to yellow.

• When 10 consecutive readings stabilize to a rate of change of 0.25% or less, the indicator turns green.

Some discretion is required to determine when the readings become stable. When the stability indicator is green, the readings may be completely stable. However, with large transformers, the last digits of the reading may continue to drift lower for a few more seconds or minutes.

Testing in Timed Mode

The Timed mode (on the 'T' version of the DWR-10) allows you to record readings at set intervals (or manually), with the time of measurement saved along with each measurement. This mode is normally used by transformer manufacturers to record several time-stamped resistance measurements in order to plot a curve of resistance versus time.

To test in Timed mode:

1. Press the Menu button and select Timed mode. The Interval Time window displays.



2. Accept or change the interval, anywhere from 5 to 100 seconds. The default is 15 seconds. A 15-second interval means the DWR-10 will perform a winding resistance test every 15 seconds, automatically. (Your chosen time interval will be displayed in the main status panel.)

3. Press the Menu button again and open the Unit Definition window.

4. Enter the serial number of the transformer (if not already entered) and other data, as desired.

5. Press the Back button.

6. Press the Tap/Winding button and enter tap and winding information.

7. At the same time, disconnect the AC source that is injecting the power transformer and press the Clock On/Off button (the measurement duration is recorded in the Total Time field on the main window).

8. Connect the test leads to the transformer windings.

9. Press the Test/Dump button to apply current.

10. When readings are stable, press the Auto On/Off button to start automatic recording of time and resistance (the countdown is recorded in the Next Meas. field on the main window).



When sufficient readings have been recorded, you can either stop the automatic measurements or test another winding.

To stop recording measurements:

1. Press either the End & Record Session button on the default toolbar, or the Clock On/Off button.

2. Press the Test/Dump button.

To test another winding:

1. Press the Auto On/Off button to stop recording (the Next meas. field will display OFF).


3. Change the windings.

4. Press the Test/Dump button again.

5. Edit the Tap and Winding fields if time permits.

6. When readings are stable, press the Auto On/Off button to start recording.

Note: Any time during Timed mode, you can also press the Save button to take additional manual measurements. The Save button is available whether or not the Auto feature is active.



Changing Windings and Testing Taps

Changing Winding Connections

If you need to change the winding connections:

1. Press the Test/Dump button to interrupt the current injection.

2. Change the winding connections.

3. Update the winding names in the Unit Definition window.

4. Press the Test/Dump button again to take new readings.

This can be repeated as many times as necessary, until you press the End & Record Session button on the default toolbar to save the manual file.

Testing Tap with On-load Tap Changer

To test a tap on a transformer with an on-load tap changer (LTC), you must first connect the DWR-10 to the tap changer control circuit.

1. Review the tap changer control drawings and connect the DWR-10's tap changer leads to appropriate points in the control circuit.

2. Ensure that the voltage and current at these points do not exceed the ratings of the DWR contacts.

3. Ensure the current is on.

4. Raise or lower the taps by pressing the Tap Changer button through the range.

5. Edit the Tap field.



6. Press the Auto On/Off button to start recording.

7. Save the reading when stable.

After raising the taps, you may need to change the connections again in order to lower the taps.

Testing Tap with De-energized Tap Changer

To test a tap with a de-energized tap changer (DETC):

1. Press the Test/Dump button to turn the current off.

2. Change taps.

3. Press the Test/Dump button again to turn the current on.

4. Edit the Tap and Winding fields.

8. Press the Auto On/Off button to start recording.

5. Save the readings when stable.

After making as many tests as you want:


2. Press the Back button to display the toolbar.

3. Press the End & Record Session button.


File Management

File Viewer The Files option in the menu list allows you to open the File Viewer to open or delete selected files, or delete all files.

Quick Start

1. Press Open File Viewer from the menu list.

2. Select and press any file.

3. Review the readings in a file by pressing the Scroll Readings button in the toolbar and turning the knob.

4. Print the readings by opening the print toolbar from the menu list and pressing the Print button.

Chapter

4

Chapter 4 — File Management


Open File Viewer

To select and open a saved file:

1. Select Open File Viewer from the menu list.

2. When the list of files appears, the first reading is highlighted blue by default. Turn the knob to highlight a different reading (if necessary).

3. Press to open the file. The Open Confirmation window displays.



4. The red frame around the Yes button indicates that Yes is selected by default. Press to open the file. (Turn the knob to select No and return to the File Viewer.)

5. Press on the Scroll Readings button to scroll through saved data by turning the knob. Newly saved data will appear on the screen, and the number of readings will be adjusted.

6. Press the Back button to de-activate the scroll function..

7. Press the Back button again to exit the File Viewer.

File Information

The File Viewer window lists the following information about each file.

Item Description Idx List order number Serial Serial number of the tested transformer (entered in

Unit Definition window) Mode Measuring mode in which the file was recorded

(M for Manual and T for Timed). No Parent file number (if the file was recorded two or

more times). OK Indicates whether the session was properly saved

and terminated (Y/N). N means the file was saved automatically because something went wrong (for example, a power loss).

Date Date information (dd mmm.yy) Time Time information (hh:mm:ss)



Delete One File

To delete a single file from the File Viewer list:

1. Press the Delete One File menu option.

2. When the list of files appears, the first reading is highlighted red by default. Turn the knob to highlight a different reading if necessary.

3. Press to delete the file.

A window displays to confirm you want to delete the file. Press Yes (the default). The file will disappear from the File Viewer list.

Press the Back button to close the File Viewer.



Delete All Files

After you have downloaded all the saved files to a PC, you can free up memory on the DWR-10 by pressing the Delete All Files menu option. A warning window displays to confirm that you want to delete all the files.

The default is No. Highlight and press Yes to delete all files.

Transferring Files to a PC The DWR-10 File Transfer software must be installed on the PC to handle the data transfer. To install, insert the CD-ROM into the PC and double-press on Setup DWR File Transfer to run the installation application.

Once you connect the DWR-10 to a PC with the RS-232 or USB cable, the instrument will automatically switch to transfer mode.

Note: You cannot transfer files when the print toolbar is open. Press the Back button to close it.

Transfer Procedure

To transfer files from the DWR-10 to the PC:

1. Connect the DWR-10 to the PC.



2. Turn on the DWR-10.

3. Press the Menu button.

4. Select Systems from the menu list.

5. Select the communication port: RS-232 or USB. (An additional driver is required for the USB port—install this on the PC from the CD-ROM provided.)

6. Close the File Viewer or any open files.

7. Connect the communications cable.

8. On the PC, double-press on the icon DWR File Transfer. This opens the file transfer software, which automatically scans the port to locate the DWR-10 connection.

• If the PC finds the DWR-10 connection, a "Connect!" message displays at the bottom left corner of the screen.

• If no connection is found, a "Not Connect" message displays.

9. On the DWR File Transfer window, select Get Files from the menu bar. All files will be copied to the directory in the PC.

10. Select Quit from the menu bar to close the application.



DWR File Transfer Window

Item Description

Quit Press to close the DWR File Transfer window Select Directory

Press to select the directory where transferred files will be stored.

Get File Press to start transferring data from the DWR-10 to the PC.

Scan Port Press to scan all available ports and check the connection with the DWR-10.

File Information

While transferring files, the DWR File Transfer window displays status messages with header information, filenames, and the number of files.

Downloaded files are standard text files with a *.txt extension. You can open files in Microsoft Excel, Word, Notepad, or any text editor.

An example of a typical filename is: 78QPCT22_T_1-Ok.txt.



Item Description 78QPCT22 Serial number of the transformer _ and - Separator characters T (or M) Test mode. 'T' is Timed mode and 'M' is Manual

mode. 1 Number of files (transformers) with the same name

(serial number) Ok (or N) 'OK' indicates that the file was saved properly.

'N' means the file was saved improperly (e.g., if the main power was lost).

.txt Filename extension



Printed Reports The following figure shows a typical DWR-10 print-out for Manual mode.

Item Description

Header The header area of the print-out displays all the information entered in the Unit Definition window (see page 24). The recorded results of each individual measurement are displayed in the columns below the file header.

Mode Displays the measurement mode for the saved file: Timed or Manual.

Date/Time Displays the date and time the file was saved.



Item Description Serial Displays the serial number of the transformer from

the Unit Definition window. The serial number becomes the file name.

Company, Station, etc.

The rest of the fields in the header display data from the Unit Definition window (see page 24).

Tap / Winding

Displays the name of the tap and winding (will be blank if nothing has been entered). The left column is for the A-channel and the right column is for the B-channel.

Res. Displays the resistance value and measurement unit (left column A-channel; right column B-channel). If a channel is off or over its range, it will display OFF or OVER.

Amp Displays the test current for the recorded measurement in amps: 10, 1.0, 0.1, or 10m.

Interval (timed mode only)

Displays (on the second row) the interval in seconds between two individual recordings of both channels (does not display for files saved in Manual mode).

Total (timed mode only)

Displays (on the second row) the time interval for each same-time recording of both channels (does not display for files saved in Manual mode).


Technical Specifications

Item Description Power Input • 90 to 132 VAC, 50/60 Hz

• 198 to 256 VAC, 50/60 Hz, 550 VA max

Test Current 10, 1, 0.1 and 0.01 amps DC Test Voltage 30 VDC Resistance Measurements

2 auto-ranging channels

Resistance Range

0.1 microohm to 2000 ohms

Protection • Protected from over-voltage transients and substation noise

• High-speed current interrupt detector • Audible warning horn during and after test • Emergency off button

Accuracy ±0.25% rdg ±0.25% FS Resolution 4½ digits Housing Rugged, waterproof case, IP-67 Weight Test set: 11.4 kg (25 lb) Dimensions Test set: 47 cm x 35.7 cm x 17.6 cm

(18½ x 14 x 6-15/16 in) Environmental • Operating temperature: 10º–50ºC

• Storage temperature: 15º–80ºC • Relative humidity: 0–90%, non-condensing

Appendix

A

Appendix A — Technical Specifications


Item Description Graphical User Interface

• 120 mm x 90 mm bright LCD display visible in bright sunlight

• Displays: Actual current, measured values, reading stability, protection status, taps, windings and transformer details

• Keypad buttons and navigation knob to configure, enter, and edit, using a virtual keyboard, menus, and toolbars

Memory At least 100 files with at least 120 measurements each in text files that are compatible with most spreadsheet formats

Embedded Software

• Menus for setting up DWR, changing languages, assigning communication ports

• File manager: files named by serial number; other data includes station, designation, manufacturer, operator, temperature, and notes

Printer Built-in, 40-character wide printer PC Connection Downloads results to PC via USB port or RS-232

connection Approvals CE compliance:

EN61010 EN61326


Connection Diagrams This Appendix contains diagrams showing various options for connecting the DWR-10 to a transformer, as well as ANSI vector diagrams and connection matrices.

Winding Diagrams

Single Phase, One Winding

Appendix

B

Appendix B — Connection Diagrams


Single Phase, Two Winding Test



Three Phase, Two Windings, Accessible Neutral



Three Phase, One Winding, Non-Accessible Neutral



Delta Delta, Two Windings



ANSI Vector Diagrams & Connection Matrices

Documents

DWR-10-User Manual Octuserequip.com/files/specs/5067/DWR-10-User Manual_Rev2.pdfDC resistance of windings is measured by passing DC current through the unknown resistance, and measuring