Raytech mini-ATOS User manual

INSTRUCTION MANUAL
ENGLISH
mini-ATOS
mini Automatic Transformer
Observation System
RAYTECH AG, OBEREBENESTRASSE 11, CH-5620 BREMGARTEN, SWITZERLAND

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Contents
1Safety Precautions.............................................................................................................. 5
1.1 Operators Qualifications .............................................................................................. 5
1.2 High Voltage Apparatus Accessibility During the Tests................................................ 5
1.3 Ground the Instrument................................................................................................. 5
1.4 Before Applying Power ................................................................................................ 6
1.5 Keep Away from Live Circuits...................................................................................... 6
1.6 Do Not Operate in An Explosive Atmosphere .............................................................. 6
1.7 Do Not Substitute Parts or Modify Instrument.............................................................. 6
1.8 Do Not Operate in A Condensing Humidity or Under Rain........................................... 6
1.9 Always Keep Distance from the Test Object During the Tests ..................................... 6
2Unpacking........................................................................................................................... 8
3Introduction......................................................................................................................... 9
4Calculation and Measurement Methods.............................................................................10
4.1 Turns Ratio Measurement...........................................................................................10
4.1.1 Principle...............................................................................................................10
4.1.2 Voltage Ratio and Turns Ratio.............................................................................10
4.1.3 Relative Error.......................................................................................................12
4.2 DC Resistance Test....................................................................................................13
4.2.1 Principle...............................................................................................................13
4.2.2 Temperature Correction.......................................................................................14
4.2.3 Resistance Deviation...........................................................................................15
4.3 Demagnetization.........................................................................................................16
4.3.1 Raytech SPP Demagnetization Method...............................................................17
4.3.2 Three-Phase Transformer Demagnetization........................................................18
4.4 Magnetic Balance.......................................................................................................19
5Measurement Setup...........................................................................................................20
5.1 Connecting Test Cables to Transformer Terminals.....................................................20
6Operation Elements...........................................................................................................22
6.1 Mains Input, Fuse and Mains Switch...........................................................................22
6.2 Ethernet Interface.......................................................................................................22
6.3 USB Interfaces (1x Host, 2x Device)...........................................................................22
6.4 Safety Indicators.........................................................................................................22
6.5 Protective Earth Terminal ...........................................................................................23
6.6 Emergency Stop.........................................................................................................23

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6.7 Display and Touch Panel............................................................................................23
6.8 Low Voltage Side Receptacles ...................................................................................23
6.9 High Voltage Side Receptacles...................................................................................23
6.10 Thermal Printer...........................................................................................................23
6.11 Tap Control.................................................................................................................23
6.12 External ......................................................................................................................23
6.13 Current Clamp Receptacle..........................................................................................23
6.14 Temperature Channels Receptacles...........................................................................23
7User Interface....................................................................................................................24
7.1 Home Screen..............................................................................................................24
7.2 Archive .......................................................................................................................25
7.3 Templates...................................................................................................................27
7.4 Settings.......................................................................................................................28
7.4.1 Date and Time.....................................................................................................28
7.4.2 Regional ..............................................................................................................28
7.4.3 Naming Scheme..................................................................................................29
7.4.4 Networking...........................................................................................................29
7.4.5 Remote Access....................................................................................................30
7.4.6 Maintenance........................................................................................................31
7.4.7 License................................................................................................................32
8Test Objects.......................................................................................................................33
8.1 Power Transformer.....................................................................................................33
8.1.1 Windings..............................................................................................................34
8.1.2 Winding Configuration Autodetect........................................................................37
8.1.3 Nameplate...........................................................................................................38
8.1.4 General................................................................................................................39
8.1.5 Tap Changer........................................................................................................41
8.1.6 Electrical Values..................................................................................................42
9Inspection and Test Plan....................................................................................................46
10 Measurements ...............................................................................................................49
10.1 Turns Ratio.................................................................................................................49
10.1.1 Table view modes................................................................................................50
10.1.2 Turns ratio settings..............................................................................................52
10.1.3 Turns Ratio Results View.....................................................................................53
10.2 Winding Resistance....................................................................................................54
10.2.1 Dual Supply Winding Resistance.........................................................................56
10.2.2 Winding Resistance Settings ...............................................................................57

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10.2.3 Winding Resistance Result View .........................................................................59
10.3 Winding Resistance Interval........................................................................................60
10.3.1 Winding Resistance Interval Settings...................................................................62
10.3.2 Winding Resistance Interval Result View.............................................................64
10.4 Demagnetization.........................................................................................................65
10.4.1 Demagnetization Settings....................................................................................67
10.5 Magnetic Balance.......................................................................................................68
10.5.1 Magnetic Balance Settings ..................................................................................70
10.5.2 Magnetic Balance Result View.............................................................................71
11 Go Taps.........................................................................................................................72
12 Remote Access Instruction.............................................................................................74
13 Interfaces.......................................................................................................................76
13.1 USB............................................................................................................................76
13.2 Ethernet......................................................................................................................76
13.3 External (4pins version)..............................................................................................77
13.4 External (6pins version)..............................................................................................78
13.5 Tap Control.................................................................................................................79
14 Technical Specifications.................................................................................................80
14.1 General.......................................................................................................................80
14.2 Accuracies..................................................................................................................81
14.2.1 Turns Ratio Measurement ...................................................................................81
14.2.2 Resistance Measurements ..................................................................................82
14.2.3 Temperature Measurement..................................................................................82
14.3 Standards and Approvals............................................................................................83
AWarranty Conditions ..........................................................................................................86
A.1 Limitation of Warranty.................................................................................................86
A.2 Arbitration...................................................................................................................87
BMaintenance......................................................................................................................88
B.1 Instrument Cleaning Instruction ..................................................................................88
B.2 How to Insert Paper into Thermal Printer....................................................................88
B.3 Thermal Printer Cleaning instruction...........................................................................89
CIndex..................................................................................................................................90
DContacts ............................................................................................................................92

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1 Safety Precautions
The following safety precautions must be observed during all phases of operation, service and
repair of this instrument. By purchasing this equipment, the purchaser assumes all liability for
the operation and use of this equipment. The intended use of the instrument, its design and
manufacture, is to be conducted within the precautions or other specific warnings located within
this manual. Failure to comply with these precautions and other specific warnings violates the
safety standards of design, manufacture, and intended use. Raytech assumes no liability for the
operation and use of this equipment.
1.1 Operators Qualifications
Only qualified, knowledgeable persons should be permitted to or attempt to operate this test
equipment. All testing personnel should fully familiarize themselves with the correct application
and operation of this and all test equipment before operation.
The measurements should never perform by only one operator without the presence of other
personnel or supervisors. Someone else other than the main operator must be aware and easily
accessible to help in case of an emergency.
1.2 High Voltage Apparatus Accessibility During the Tests
Persons directly and indirectly engaged in the operation of this test equipment should keep
clear of all high voltage apparatus while conducting tests and measurements. A barrier band
must always use so the test object under the test is not accessible to any person during the test.
1.3 Ground the Instrument
The power cord supplied with the equipment must be connected to an electrical receptacle with
an electrically grounded terminal (earthed ground). To minimize shock hazards, the ground
terminal on the instrument must be properly connected to the earth point. In many cases, the
quality of the safety ground terminal provided by the power cord does not fulfil the safety
requirements.
Never connect the instrument to an energized transformer!
WARNING!
Non-grounded instruments are dangerous and may cause damage to
personnel and to the instrument.
WARNING!

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1.4 Before Applying Power
Read this manual carefully before operating the system. The instrument is line operated. The
system is designed to be used with either 110VAC or 230VAC 50/60 Hz. The system performs
a self-check each time that it is powered on.
1.5 Keep Away from Live Circuits
Operating personnel must not remove instrument covers. Component replacement and internal
repairs must be made by qualified service personnel. Do not replace components or service this
instrument with the power cable connected. To avoid injuries, always discharge circuits,
disconnect power and remove external voltage sources before touching components.
1.6 Do Not Operate in An Explosive Atmosphere
Do not operate the instrument in the presence of flammable gases or fumes.
1.7 Do Not Substitute Parts or Modify Instrument
Because of the danger of introducing additional hazards, do not install substitute parts or
perform any unauthorized modification to the instrument. Return the instrument to a Raytech
service department for service to ensure proper operation and that safety features are
maintained.
Instruments, which appear damaged or defective, should be made inoperative and secured
against unintended operation until they can be repaired by qualified service personnel.
1.8 Do Not Operate in A Condensing Humidity or Under Rain
Operating the instrument in condensing humidity or under the rain can introduce an electric
shock hazard for the user and also can damage the instrument. This instrument is not supposed
to be installed permanently outdoor.
1.9 Always Keep Distance from the Test Object During the Tests
During performing the tests, there may be a hazardous voltage at the terminals of the test
object. Always keep a distance of a minimum of 1.5m from the test object. The unsafe area
must be specified and restricted with barrier tapes or ropes like Figure 1. Enter the area only
when not testing and when the instrument shows that there is no output voltage which is
specified when the green light indicator on the front panel is on.

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Figure 1: The unsafe area must be specified and restricted with barrier tapes or ropes
Always keep distance from the test object during the tests and the
unsafe area must be specified and restricted with barrier tapes or
ropes
WARNING!

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2 Unpacking
The Instrument
Cable Bags
Measuring Cables H (H0-H3)
Measuring Cables X (X0-X3)
Safety Ground Cable
Power Cord
Spare Paper rolls & Fuses
USB Memory Stick
Instruction Manual (Pre.)

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3 Introduction
The Raytech precision mini–Automatic Transformer Observation System (mini-ATOS) is a
professional multifunctional power transformer and substation diagnosing test instrument
developed by Raytech engineers. It is designed for a high degree of accuracy and ease of use.
This compact and intelligent instrument can perform many routines and advanced tests such as
Winding Resistance (WR), Dynamic Resistance Measurement (DRM), Turns Ratio (TR),
Frequency Response of Stray Losses (FRSL), Magnetic Balance, and other diagnostic
parameters. With the built-in fully automatic multiplexer, only a one-time connection is required for
nearly all functions which saves a considerable amount of time. The portable, rugged case is
perfect for use anywhere onsite or in a laboratory. It is specially designed for fast and easy
measurements with the well-known high precision and quality of all Raytech instruments.
The mini-ATOS field case is a waterproof design (IP67). A pressure
regulator activates when the case is opened to compensate for
atmospheric pressure changes.
INFO:

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4 Calculation and Measurement Methods
4.1 Turns Ratio Measurement
4.1.1 Principle
The transformer turns ratio test is used for measuring the ratio of turns of wires of the two sets of
windings e.g., the primary side and the secondary side of a transformer. The Turns Ratio test does
not tell exactly how many turns of wire are in each coil, but rather, it measures and displays the
ratio of the number of turns of two coils.
This is a useful test to check for shorted turns and also to find probable incorrect settings of tap
changers during manufacturing or repairing.
The mini-ATOS performs the turns ratio by applying voltage on the high voltage side of each phase
and measuring the applied voltage and transformed voltage. Figure 2 represents the very simple
schematic of the measuring circuit.
Figure 2: Very simple schematic of mini-ATOS turns ratio measuring circuit
The excitation current is also measured during the turns ratio test. The value of the excitation
current has a direct relation to the test voltages. A higher test voltage leads to a higher excitation
current. Additionally, the phase angle between the applied voltage and the transformed voltage is
also measured and is included in the results.
4.1.2 Voltage Ratio and Turns Ratio
It is important to understand the differences between transformer voltage ratio and transformer
turns ratio. The voltage ratio is the ratio of rated voltages of two windings but the turns ratio is
exactly the ratio of the number of turns of two sets of windings. For a single-phase Transformer,
the Turns Ratio is the same as the Voltage Ratio, however for a three-phase transformer they may
be different.
As an example, consider a single-phase transformer schematic with a primary side and a
secondary side. The primary side nominal voltage which is written on the nameplate is 6900V and
from the manufacturing data, we know it consists of 15000 turns. And secondary side nominal