GE Kelman DGA 900 Plus Guide

GEDE-GA_M-DLIS-TE.MA-041 Rev 1.1 4-Mar-22
GE
Grid Solutions
Kelman™ DGA 900 Plus
Transformer Monitoring System
Installation & Commissioning Manual

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 2 of 99
Contents
Page
1Introduction......................................................................................................7
1.1 Product Overview................................................................................................................................7
1.2 Scope ........................................................................................................................................................7
2Safety .................................................................................................................8
2.1 Symbols ...................................................................................................................................................8
2.2 Safety Statements..............................................................................................................................8
3Technical Specifications ..............................................................................10
4Compliance .....................................................................................................12
5Transformer Monitoring System (TMS)...................................................13
5.1 TMS Options .......................................................................................................................................15
6Card Option #1: Thermal Models...............................................................17
6.1 Sensor Input Configuration..........................................................................................................17
6.2 Wiring....................................................................................................................................................17
6.3 Temperature Sensors.....................................................................................................................18
6.4 CT Sensors...........................................................................................................................................21
7Card Option #2: Cooling Status Monitor .................................................23
7.1 Sensor Input Configuration..........................................................................................................23
7.2 Wiring....................................................................................................................................................24
8Card Option #3: OLTC Monitor...................................................................26
8.1 Sensor Input Configuration..........................................................................................................26
8.1.1 Tap Position Sensor.........................................................................................................................................26
8.1.2 Motor Torque Measurement........................................................................................................................26
8.2 Motor Power Converter.................................................................................................................30
9Card Option #4: Bushing & PD Monitor....................................................33
9.1 Installation Layout...........................................................................................................................33
9.2 Inside the Hub Module...................................................................................................................34
9.3 Power & Communications ...........................................................................................................36
9.4 Bushing Adaptors.............................................................................................................................36
9.4.1 Bushing Adaptor Cables ................................................................................................................................37
9.4.2 Install a Bushing Adaptor ..............................................................................................................................44
9.5 High Frequency Current Transformer (HFCT) .....................................................................47
9.6 Magnetically Mounted Temperature Sensors .....................................................................50
9.7 Cabinet Connections ......................................................................................................................52
9.7.1 Bushing Adaptors & Neutral CT(s).............................................................................................................52
9.7.2 Magnetically-Mounted Temperature Sensors ......................................................................................53
9.8 Bushing Adaptor Circuit Integrity Test Record....................................................................54
9.8.1 Required Material.............................................................................................................................................54
9.8.2 Test Procedure ..................................................................................................................................................55
10 Commissioning & Service ............................................................................71
10.1 Factory Settings................................................................................................................................71
10.2 Models...................................................................................................................................................72
10.3 OLTC Monitor Commissioning....................................................................................................73
10.3.1 Prerequisite Commissioning Steps ...........................................................................................................74
10.3.2 Establish Baseline Settings ..........................................................................................................................77
10.3.3 Download DGA 900 Plus data to Perception.........................................................................................79
10.3.4 Generate Configuration Files.......................................................................................................................81

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10.3.5 Import Configuration Files to DGA 900 Plus..........................................................................................85
10.3.6 Finalisation..........................................................................................................................................................85
10.4 Bushing & PD Monitor Commissioning...................................................................................87
10.4.1 General Settings ...............................................................................................................................................87
10.4.2 Voltage Measurement ....................................................................................................................................87
10.4.3 C1% Measurement ..........................................................................................................................................88
10.4.4 C.4 Tan δ(Power Factor) Measurement .................................................................................................89
10.4.5 PD Live HF Noise Threshold Measurement............................................................................................90
10.4.6 PDI Associated Power Measurement.......................................................................................................91
10.4.7 PD Average Apparent Charge Measurement ........................................................................................92
10.4.8 PD Max Apparent Charge Measurement ................................................................................................92
10.4.9 Export Setting ....................................................................................................................................................94
10.4.10 Finalisation ........................................................................................................................................................95
Parts and Tools List for Bushing & PD monitor.....................96
A.1 GE-supplied items (shipped with the product)...................................................................96
A.2 GE Field Service Engineer (FSE)-supplied items.................................................................97
A.3 Customer-supplied Items.............................................................................................................98
Contact & Copyright Details ...............................................................................99

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List of Tables and Figures
Page
Table 3-1: Measurements & Operating Specifications.......................................................................... 10
Table 4-1: Type Tests .............................................................................................................................. 12
Figure 5-1: TMS inputs overview ............................................................................................................ 13
Figure 5-2: Option packs dataflow ......................................................................................................... 14
Figure 5-3: Hub module PCB faceplates................................................................................................. 15
Table 5-1: DGA 900 Plus card options.................................................................................................... 16
Table 6-1: Thermal Models inputs .......................................................................................................... 17
Figure 6-1: Thermal Models wiring......................................................................................................... 18
Figure 6-2: Magnetic mount temperature sensor ................................................................................. 19
Table 6-2: Oil temperature sensor specification ................................................................................... 19
Figure 6-3: Magnetic mount temperature sensor –installation overview........................................... 20
Figure 6-4: Split core CT.......................................................................................................................... 21
Table 6-3: CT dimensions........................................................................................................................ 21
Table 6-4: CT specifications .................................................................................................................... 22
Table 6-5: CT options .............................................................................................................................. 22
Table 7-1: Cooling Status inputs............................................................................................................. 23
Figure 7-1: Cooling Banks –analogue inputs & CTs............................................................................... 24
Figure 7-2: Cooling Banks –digital inputs (25 mA max & 24 V max) ................................................... 25
Table 8-1: OLTC Monitor inputs.............................................................................................................. 26
Figure 8-1: OLTC Monitor wiring –three phase..................................................................................... 28
Figure 8-2: OLTC Monitor wiring –single phase .................................................................................... 29
Figure 8-3: Power Converter................................................................................................................... 30
Figure 8-4: Power Converter –specifications & dimensions ................................................................ 30
Figure 8-5: Power Converter –wiring example...................................................................................... 31
Figure 9-1: General installation layout –single transformer ................................................................ 34
Figure 9-2: General installation layout –bank of 3 single phase transformers ................................... 34
Figure 9-3: Hub module .......................................................................................................................... 35
Figure 9-4: Hub module with Thermal Models and Bushing Monitor cards ......................................... 35
Figure 9-5: Bushing Adaptor –without top cover.................................................................................. 37
Figure 9-6: Bushing Adaptor –with top cover ....................................................................................... 37
Table 9-1: GE-supplied materials ........................................................................................................... 38
Table 9-2: Customer-supplied tools....................................................................................................... 39
Table 9-3: Coaxial cable preparation...................................................................................................... 39
Table 9-4: Connecting to the Bushing Adaptor...................................................................................... 40
Table 9-5: Connecting to the grounding switch..................................................................................... 41
Table 9-6: Connecting to the Neutral CT................................................................................................ 42
Figure 9-7: Bushing Adaptor with cap.................................................................................................... 44
Figure 9-8: Bushing Adaptor with initial threads covered in grease..................................................... 45
Figure 9-9: Bushing Adaptor with all threads covered in grease .......................................................... 45
Figure 9-10: Liquid-tight fitting thread................................................................................................... 46
Figure 9-11: Bushing adaptor terminal block......................................................................................... 46
Figure 9-12: Tightening order ................................................................................................................. 47
Figure 9-13: HFCT cannot be installed if a switch is on cable from the Neutral Bushing to ground... 48
Figure 9-14: HFCT installed on cable from the Neutral Bushing (H0) directly to ground .................... 48
Figure 9-15: Star configuration (Y-Connection)..................................................................................... 49
Figure 9-16: HFCT installed after the switch on cable from the Neutral Bushing to ground .............. 49
Figure 9-17: HFCT –example.................................................................................................................. 50
Figure 9-18: MMTS rear view .................................................................................................................. 50
Figure 9-19: MMTS front view................................................................................................................. 50

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Figure 9-20: MMTS side view - #1........................................................................................................... 50
Figure 5-21: MMTS #1 with jumper ........................................................................................................ 51
Figure 5-22: MMTS #2/3 without jumper ............................................................................................... 51
Figure 9-23: Bushing adaptor connections ............................................................................................ 52
Figure 9-24: CANbus Connection on the DIN rail .................................................................................. 53
Figure 9-25: Coax BNC to clips cable...................................................................................................... 54
Figure 9-26: Two-pin connector and release key .................................................................................. 54
Figure 9-27: Primary and secondary switches closed to isolate signal ................................................ 55
Figure 9-28: AntScope New measurement –Configure > AA-170 Analyzer........................................ 56
Figure 9-29: Open calibration ................................................................................................................. 56
Figure 9-30: Limits scan range................................................................................................................ 57
Figure 9-31: AntScope measurement - Open........................................................................................ 57
Figure 9-32: Configure > Save last measured data > as “open” calibration ......................................... 58
Figure 9-33: Save As “calibOpen” ........................................................................................................... 58
Figure 9-34: Short calibration................................................................................................................. 59
Figure 9-35: AntScope measurement - Short........................................................................................ 59
Figure 9-36: Configure > Save last measured data > as “short” calibration......................................... 60
Figure 9-37: Save As “calibShort” ........................................................................................................... 60
Figure 9-38: Load calibration.................................................................................................................. 61
Figure 9-39: AntScope measurement - Load......................................................................................... 61
Figure 9-40: Configure > Save last measured data > as “load” calibration........................................... 62
Figure 9-41: Save As “calibLoad” ............................................................................................................ 62
Figure 9-42: Bushing adaptor measurement......................................................................................... 63
Figure 9-43: AntScope measurement - AdaptorOnly............................................................................ 63
Figure 9-44: Save As “AdaptorOnly”....................................................................................................... 64
Figure 9-45: Save As “AdaptorInstalled” ................................................................................................ 64
Figure 9-46: AntScope measurement - AdaptorInstalled ..................................................................... 65
Figure 9-47: AntScope measurement –AdaptorInstalled (with Cpar measurement)......................... 65
Figure 9-48: Resistance between cable shield and ground................................................................... 66
Figure 9-49: Resistance measurement .................................................................................................. 67
Figure 9-50: Bushing Adaptor Calibration Data..................................................................................... 67
Figure 9-51: R2 resistance measurement.............................................................................................. 68
Figure 9-52: Calibration - Input Impedance ........................................................................................... 68
Figure 9-53: R3 total resistance measurement ..................................................................................... 69
Figure 9-54: Input voltage measurement .............................................................................................. 69
Table 9-7: Results.................................................................................................................................... 70
Figure 10-1: Service > Factory Settings.................................................................................................. 71
Figure 10-2: Service > Models................................................................................................................. 72
Table 10-1: OLTC software requirements.............................................................................................. 73
Table 10-2: OLTC files ............................................................................................................................. 74
Figure 10-3: Successful connection to DGA 900 Plus............................................................................ 74
Figure 10-4: OLTC Model Alarms Configuration .................................................................................... 75
Figure 10-5: OLTC Motor Torque Total Time (%) ................................................................................... 76
Figure 10-6: OLTC Motor Torque Total Time (%) –Alerts Off ............................................................... 76
Figure 10-7: OLTC Tap Position Tracking Configuration –parameters ................................................ 77
Figure 10-8: Configuration Import –TapPositionCalibration.cfg .......................................................... 78
Figure 10-9: OLTC Motor Torque Configuration - parameters.............................................................. 78
Figure 10-10: Tap position movements —an example ......................................................................... 79
Figure 10-11: New > DGA 900 Plus database ........................................................................................ 80
Figure 10-12: Add / Remove Measurements Points > Tap Position & OLTC Motor Torque ................ 81
Figure 10-13: Microsoft Excel —Commissioning_Document_v1.2 —Dashboard homepage ............. 82
Figure 10-14: TapPositionCalibration.cfg............................................................................................... 83

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Figure 10-15: OltcGroups.cfg.................................................................................................................. 84
Figure 10-16: OltcRefData.cfg................................................................................................................. 84
Figure 10-17: Required files for OLTC commissioning .......................................................................... 85
Figure 10-18: Configuration Import –TapPositionCalibration.cfg, OltcGroups.cfg & OltcRefData.cfg85
Figure 10-19: OLTC Tap Position Tracking Configuration...................................................................... 86
Figure 10-20: BMT > General Settings.................................................................................................... 87
Figure 10-21: BMT > Configuration......................................................................................................... 87
Figure 10-22: Voltage Measurement...................................................................................................... 88
Figure 10-23: Bushing ............................................................................................................................. 88
Figure 10-24: Exponential Moving Average Configuration.................................................................... 89
Figure 10-25: Measured Phase Angle..................................................................................................... 89
Figure 10-26: Bushing Alarms Configuration......................................................................................... 90
Figure 10-27: Exponential Moving Average Configuration.................................................................... 90
Figure 10-28: Live HF Noise .................................................................................................................... 90
Figure 10-29: HF Gain Control ................................................................................................................ 91
Figure 10-30: PD > Primary > Associated............................................................................................... 91
Figure 10-31: PD Alarms Configuration > Primary PDI .......................................................................... 92
Figure 10-32: PD > Primary > Avg Apparent Charge.............................................................................. 92
Figure 10-33: PD Alarms Configuration > Primary PD value ................................................................. 92
Figure 10-34: PD > Primary > Max Apparent Charge............................................................................. 93
Figure 10-35: PD Alarms Configuration > Primary PD value ................................................................. 94
Figure 10-36: PD Alarms Configuration > Primary B PD Max ................................................................ 94
Figure 10-37: PD Alarms Configuration > Primary C PD Max ................................................................ 94
Figure 10-38: BMT > General Settings.................................................................................................... 95
Figure 10-39: Bushing Adaptor Failure Alarms...................................................................................... 95
Table A-1: GE-supplied items ................................................................................................................. 96
Table A-2: GE FSE-supplied items .......................................................................................................... 97
Table A-3: Customer-supplied items...................................................................................................... 98
Related Documents
Ref#
Title
MA-024
DGA 900 Installation Manual
MA-025
DGA 900 Operator Guide
MA-040
DGA 900 Plus - Operator Guide
Abbreviations & Definitions
Abbreviation
Meaning
HFCT
High Frequency Current Transformer
HMI
Human Machine Interface
HV
High Voltage
LOTO
Lock Out, Tag Out procedure
LV
Low Voltage
OLTC
On Load Tap Changer
PD
Partial Discharge
RTD
Resistive Temperature Detectors

MA-040 –DGA 900 Plus - Operator Guide - Rev 1.1 4-Mar-22 Page 7 of 99
1INTRODUCTION
1.1 Product Overview
The Kelman™ DGA 900 Plus (the product) builds on the existing multi-gas online DGA
900 system with additional monitoring capabilities and a series of data models to
provide a complete transformer monitoring solution. This flexible offering combines the
latest technology and a range of options via a modular and retrofittable architecture. The
product uses additional sensors and electronic cards to gather and process key
transformer operational data. The latest firmware is embedded with intelligent
algorithms that utilise this data to determine incipient transformer faults early. Other
important transformer characteristics are also monitored and together this delivers an
integrated and comprehensive assessment of transformer health. Depending on the
options chosen, the product offers the following capabilities:
▪Thermal models
▪Cooling status
▪OLTC monitoring
▪Bushing monitoring & Partial Discharge (PD) detection
▪Perception Fleet software
1.2 Scope
This manual must be read in conjunction with the standard DGA 900 manuals as listed in
the Related Documents section above. The standard ‘DGA 900 Installation Manual’
provides important pre-installation considerations and core installation details that
must be read prior to installation in order to prepare the site and obtain the necessary
equipment in advance of the installation.
This product contains additional sensors, electronic cards and firmware to provide a rich
monitoring and modelling feature set as described in the respective Operator Guides.
Principally, this manual describes the Hub module and all hardware installation tasks
that are unique to the ‘Plus’ designation pertaining to thermal models, cooling status,
OLTC monitoring, bushing and partial discharge monitoring, such as bushing adaptor
connections, temperature sensors, CTs, related wiring details and preparatory tasks. This
manual also describes essential configuration operations and first start-up procedures
that must be done in the HMI as part of the commissioning phase. To configure and
generate all the data models, including setting alarms, refer to the ‘MA-040 –DGA 900
Plus –Operator Guide’. For all other aspects of the installation, particularly regarding the
Analysis module including standard requirements and safety statements, refer to the
standard DGA 900 Installation Manual.
The ‘DGA 900 Plus’manuals build on the standard ‘DGA 900’manuals referenced in the
Related Documents table above, and together they form the comprehensive ‘DGA 900
Plus’ documentation set. Collectively the manuals examine installation for all options
including mounting, plumbing, power, electronics and communications, and
comprehensive use of the HMI for configuration, communications, alarm settings,
calculations and error notifications to avail of all monitoring and modelling functionality.

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 8 of 99
2SAFETY
2.1 Symbols
The meaning of symbols used on the Kelman™ DGA 900 Plus:
Caution. Refer to the Installation Manual / Operator Guide to prevent death,
injury, equipment damage or loss of data.
Electrical Hazard. Risk of electric shock.
Primary Protective Earth connection.
Hot surfaces may be present.
The meaning of symbols used in this manual:
WARNING
A procedure, practice, or condition could cause death or serious injury
and/or significant equipment damage.
A procedure, practice, or condition could cause minor injury, equipment
damage or loss of data.
Electrical Hazard: Risk of electric shock.
2.2 Safety Statements
The following safety statements must be observed:
The customer and installer are responsible for ensuring that all local
regulations and site policies are complied with concerning safe working
practices.
The minimum ambient temperature for installation and service activities is
−10 °C..
If the equipment is installed or used in a manner not specified by the
manufacturer, the protection provided by the equipment may be impaired.
If working at height, third parties must have received appropriate training
for working at height prior to work commencing. This includes, but is not
limited to, ‘Working at height’ and ‘Using Mobile Elevated Working
Platforms’ training.

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If working at a height greater than 4 feet (1.2 metres) or at a height greater
than that stipulated by national or site regulatory requirements, it is the
responsibility of the installer to ensure that planned work complies with
those requirements.
The installer shall also ensure that any third-party equipment, such as an
approved platform, scaffold or lift is suitable and safe before commencing
work. Ladders or improvised platforms do not meet GE service engineer
requirements.
Do not open the cabinet during inclement weather.
Before commencing any installation or maintenance work, ensure that the
product is disconnected from the mains supply via the external switch or
circuit breaker.
Once installed, this product may have more than one source of electrical
supply. Disconnect all supplies at their source before accessing the cabinet
for servicing. Follow the site lockout-tagout (LOTO) procedure.
Ensure all power sources, including relays, are de-energised as stipulated
by lockout-tagout (LOTO) requirements before performing any
maintenance work inside the product.
The product is operated with the door shut under normal use. The door
shall be kept locked and should only be opened for service access by
suitably qualified and authorised service personnel. During service access,
hazardous voltages are accessible
Only GE-trained and certified personnel may commission GE Kelman
products. Commissioning tasks include making any connections and/or
performing any work within the module, or performing tasks such as
purging the oil circuit between the transformer and the product, and/or all
first start-up procedures relating to equipment or firmware/software.
WARNING: All procedures in this manual must be followed. Any deviation
could cause irreversible damage to the transformer being monitored and/or
the product, and could lead to property damage, personal injury and/or
death.
Bushing monitoring falls outside the scope of UL61010-1 and CSA C22.2 No.
61010-1 and has not been evaluated. When these products are installed in
the United States and Canada, use of bushing monitoring voids the UL
listing / certification of the product.

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3TECHNICAL SPECIFICATIONS
The product meets the following technical specification as outlined in Table 3-1.
Table 3-1: Measurements & Operating Specifications
BUSHING & PD MEASUREMENTS
Input current measuring range
2 mA –200 mA rms, 1% of reading
Relative phase angle accuracy
0.01 deg of angle
Maximum number of PD measured
200 pulses per cycle (50 to 60 Hz)
Measurement category for signal inputs
CAT III. 5 V AC rms, 200 mA; on each phase
Maximum bushing temperature at bushing adaptor
90 °C (194 °F)
ENVIRONMENTAL
Unit operating temperature
−40 °C to 55 °C (−22 °F to 131 °F)
Bushing adaptor operating temperature
−40 °C to 90 °C (−40 °F to 194 °F)
at bushing tapping point
Storage temperature
0 °C to 45 °C (−32 °F to 113 °F)
Altitude
Up to 2000 m (6500 ft) above sea level
Atmospheric pressure
Up to 1050 mbar
Operating humidity
10 –95% RH non-condensing
Enclosure*1
IP56, NEMA 3RX
Bushing adaptors
IP66
Weight *2
Analysis module: 33.4 kg (73.6 lb)
Hub module: 22.2 kg (48.9 lb)
2 m PCC cable: 0.8 kg (1.83 lb)
Product weight: 56.4 kg (124.33 lb)
Bushing adaptor (each): 0.350 g (0.8 lb)
Pollution degree
2
POWER
Nominal input voltage range:
100-250 V DC 4 A
100-240 V AC, 50/60 Hz, 4 A
Input voltage range:
90-264 V AC
90-275 V DC
AC frequency range:
45-65 Hz
Single phase Alarm Relays: NO and NC provided*3
10 A 250 V AC, 10 A 30 V DC,
0.3 A 110 V DC, 0.12 A 220 V DC
Over Voltage Category
II
Fuses *4
10 A 600 V AC/DC EATON KLM-10
DC distribution fuses –Schurter Series SPT
250V DC 8 or 6.3 A
Coin cells
Panasonic CR2450 3 V 620 mAh
TOP OIL TEMPERATURE SENSOR (Bushing Monitor)
Operating Voltage
12 V DC
Communication
CAN bus
TOP OIL TEMPERATURE SENSOR (Models)
Communication
4-20 mA

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*1 Note: It is possible for a small amount of condensation to form on the inner surface of
the Analysis enclosure. This occurs under certain environmental conditions and
does not affect the performance or reliability of the product.
*2 Note: The weight depends on the order specification. The stated weight is for a base
product without packaging and excludes options such as a mounting stand.
Check the shipping document for the exact packaged weight.
*3 Note: Maximum DC breaking capacity for a resistive load.
*4 Note: Use only the approved and recommended fuse to ensure continued fire
protection and compliance.

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4COMPLIANCE
The product is designed to meet the following type tests as listed in Table 4-1.
Table 4-1: Type Tests
CATEGORY
STANDARD
Performance
Criteria
TEST
EMC Emissions
EN 61326-
1:2006
CISPR 11
A
Radiated & Conducted Emissions
FCC Part 15
Meets the
requirements of A
Radiated & Conducted Emissions
EN 61000-3-2
A
Harmonic Current Emissions
Limits
EMC Immunity
EN 61326-
1:2006
IEC 61000-6-5:
2015
EN 61000-4-2
B
Electrostatic Discharge
EN 61000-4-3
A
Electromagnetic Field Immunity
EN 61000-4-4
B
Electrical Fast Transients
EN 61000-4-5
B
Surge Immunity
EN 61000-4-6
A
Conducted RF Immunity
EN 61000-4-8
A
Magnetic Field Immunity
EN 61000-4-11
B, C
Voltage Dips & Interruptions
IEC 61000-4-16
A
Mains frequency voltage
IEC61000-4-17
A
Ripple on DC power supply
IEC61000-4-18
B
Damped oscillatory wave
EN 60255-5
5 kV, 2 kV &
500 V DC
Impulse, Dielectric & Insulation
resistance testing
Environmental
Tests
IEC 60068-2-1
−40 °C
Cold
IEC 60068-2-2
55 °C
Dry Heat
IEC 60068-2-6
10 –500 Hz,
0.5 g operation
10 –500 Hz,
1 g endurance
Vibration
IEC 6IEC0068-2-
30
55 °C, 95% RH
Damp Heat
IEC60068-2-6
Vibration (sinusoidal)
IEC60068-2-27
Vibration (bump, shock)
EN 60529
IP56
Degree of Protection
Safety
IEC 61010-1
2010
EN 61010-1
2010
UL61010-1*5
CSA C22.2 No.
61010-1*5
*5 Note: Bushing monitoring falls outside the scope of UL61010-1 and CSA C22.2 No.
61010-1 and cannot be included in any third-party certification for North
America.

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 13 of 99
5TRANSFORMER MONITORING SYSTEM (TMS)
A fully integrated TMS is illustrated in Figure 5-1. In addition to the analytics performed
on dissolved gases, the DGA 900 Plus accepts multiple inputs from an array of sensors.
Figure 5-1: TMS inputs overview
These sensors gather operational data on the internal workings of a transformer that
allow the DGA 900 Plus to:
▪produce thermal models on key aspects of a transformer’s condition
▪monitor and model the cooling status of fans and pumps
▪monitor the condition of the OLTC mechanism
▪monitor 3/6 bushings
These capabilities are delivered by several TMS option packs that are installed in the Hub
module and are field retrofittable. Each pack has dedicated PCB card options and are
supplied with the relevant sensors (unless otherwise stated). These cards receive the
sensor data and process it according to advanced algorithms. Some interdependencies
do exist between the various cards with some inputs and outputs feeding into other
models as illustrated by the relationship schematic shown in Figure 5-2.
Note: Consult with your GE representative to ensure that the correct option pack(s)
are part of your installation.

MA-040 –DGA 900 Plus - Operator Guide - Rev 1.1 4-Mar-22 Page 14 of 99
Figure 5-2 illustrates the dataflow, inputs and relationships between the various option packs.
Figure 5-2: Option packs dataflow

MA-040 –DGA 900 Plus - Operator Guide - Rev 1.1 4-Mar-22 Page 15 of 99
5.1 TMS Options
The Hub module has four PCB slots as shown in Figure 5-3. From left to right, the first
slot houses the Controller PCB as described in the standard DGA 900 Installation
manual. Depending on the chosen combination of options, the other three slots as
highlighted house the I/O cards for the additional analogue and digital inputs related to
the additional modelling and monitoring capabilities.
Figure 5-3: Hub module PCB faceplates
The four available card options are:
Thermal Models_Card_Option_#1:
Cooling Status Monitor
OLTC Monitor
Bushing Monitor
The system can host up to any three of the above four card options.

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Table 5-1 lists all the permutations for the four cards in the three slots.
Table 5-1: DGA 900 Plus card options
Slot 1
Slot 2
Slot 3
Default Card
-
-
Thermal Models
-
-
Thermal Models
Cooling Status
-
Default Card
-
Bushing Monitor
Thermal Models
-
Bushing Monitor
Thermal Models
Cooling Status
Bushing Monitor
Default Card
OLTC Monitor
Bushing Monitor
Default Card
OLTC Monitor
-
Thermal Models
OLTC Monitor
-
Thermal Models
OLTC Monitor
Bushing Monitor
Thermal Models
Cooling Status
OLTC Monitor
The default card refers to the DGA 900 I/O PCB card as described in the standard DGA
900 Installation Manual.
The required sensors must be installed as per the standard common input sensors (4-20
mA, RTD and/or CT). The I/O PCB has six analogue inputs as standard (five of which are
customer configurable) and three digital inputs. The final configuration for each board is
different depending on the option packs chosen. A label on the PCB faceplate indicates
the final configuration. All sensors are supplied as part of the package (unless otherwise
requested/stated).
The product is supplied with factory default settings for all parameters, e.g. alarm
thresholds. For optimal performance, specific settings are required for each installation
and for the OLTC and Bushings monitors, precise commissioning steps must be followed
as defined in Section 10.3 and Section 10.4 respectively. For all other operational details
relating to the software interface for configuration, bushing settings, data readings and
alarms, refer to the ‘MA-040 –DGA 900 Plus –Operator Guide’.
Note: The Analysis module is dedicated to dissolved gas analysis as outlined in ‘MA-
024 - DGA 900 Installation Manual’ & ‘MA-025 - DGA 900 Operator Guide’.

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 17 of 99
6CARD OPTION #1: THERMAL MODELS
The thermal card option generates the base models relating to thermal and moisture
readings. It integrates data from the existing DGA analysis (for moisture and ambient
temperature) and accepts inputs from two 4-20 mA inputs to obtain top- and bottom -oil
temperatures (see Section 6.3) and up to three split core CT sensors for transformer load
(see Section 6.4).
6.1 Sensor Input Configuration
Table 6-1 lists the types of inputs used by the Thermal Models.
Table 6-1: Thermal Models inputs
Input
Label
Sensor Type
AIN 1
CT H/H/A/H
CT
AIN 2
CT X/X1/B/C
CT
AIN 3
CT Y/X2/C/Y
CT
AIN 4
Top Oil Temperature
4-20 mA
AIN 5
Bottom Oil Temperature
4-20 mA
AIN 6
spare
None / CT / 4-20 mA / RTD
DIN 1
spare
12-24 V
DIN 2
spare
12-24 V
DIN 3
spare
12-24 V
Note: The default range for the Thermal CTs is 0-5 A. Other ranges are available on
request with advance notice.
Thermal Models requires the installation and wiring of up to three CTs and two
temperature sensors provided with the Thermal Models pack. These are to be wired as
shown in Figure 6-1 and in accordance with the ‘MA-024 –DGA 900 Installation Manual’.
The Top Oil Temperature sensor should be installed in a vertical position on one of the
long sides of the transformer, typically between 20-30 cm from the top, and horizontally
in the middle. The Bottom Oil Temperature sensor should be installed as per the Top Oil
Temperature sensor, but 20-30 cm from the bottom.
6.2 Wiring
The wiring for the Thermal Models is shown in Figure 6-1. Wetting terminals accept up to
14 24 V DC connections with a cable cross section of 0.14 mm² to 2.5 mm², AWG: 14 –
26.

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 18 of 99
Figure 6-1: Thermal Models wiring
Figure 6-2 to Figure 6-4 below show the temperature sensors and CT in detail.
6.3 Temperature Sensors
The temperature sensors measure the top and bottom oil temperatures of the main tank
and the OLTC temperature. An example is shown in Figure 6-1 and comprises of a self-
contained PT100 with a built-in 4-20 mA transmitter which is powered from the
monitoring unit and provides a 4-20 mA output that is read by the analogue input card.
The temperature sensor is enclosed in a plastic weatherproof housing and magnetically
mounts to the side wall of the transformer main tank or the OLTC side wall.

MA-041 –DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1 4-Mar-22 Page 19 of 99
Figure 6-2: Magnetic mount temperature sensor
The oil temperature sensor specification is shown in Table 6-2.
Table 6-2: Oil temperature sensor specification
Item
Value
Enclosure
Plastic
Output
4-20 mA
Wiring
12 m (40 ft) twisted, shielded pair 22 AWG & thermal compound
Operating
temperature
−40 °C to 150 °C (−40 °F to 302 °F)
Size
5.7 × 4.7 cm (2.25 × 1.87 in.)
Weight
230g (8 oz) excluding wire
300 g (11 oz) including wire
Power Requirements
24 V DC
Note: The cable length provided with the temperature sensor is 40 feet (approx. 12
metres).

MA-040 –DGA 900 Plus - Operator Guide - Rev 1.1 4-Mar-22 Page 20 of 99
An overview to the fitting of a magnetic mount temperature sensor to the tank wall is shown in Figure 6-3.
Figure 6-3: Magnetic mount temperature sensor –installation overview