This document describes a carbon nanotube sensor system for monitoring transformer insulation oil. It consists of 3 sentences: The system uses a carbon nanotube sensor to detect combustible gases produced from degradation of insulation oil. It can continuously monitor multiple transformers in real-time through a wireless network. Test results showed the carbon nanotube sensor accurately measured changes in combustible gases compared to gas chromatography analysis.

1. September 2011
Transformer Insulation Oil
Sensing System
0
Unique Sensing Solution
www.snsrevolution.co.kr
Sensor & System Technology
Doc T-1

2. 1
Core Technology
“Carbon Nano-Tube (CNT) Sensor”- Unique Technology”
CNT
Features
CNT has characteristics such as nanometer diameters,
cylindrical structures
Chemical features to absorb and desorb by molecular
unit and far larger surface compared to volume
Application Technology
Major contents of oil, “HYDROCARBONS” undergoes chemical changes by heat
and light, generating combustible gases such as CH4, C2H2, C2H6, C2H4, C3H8
H2 and combustible gases are absorbed in the surface of CNT sensor, making
conductance changed. The measured conductance difference will then be
converted into PPM value.
Unique Sensing Solution

3. 2
Core Technology
Measuring Gas
CNT Sensing Mechanism
• Electrons being adsorbed onto the nanotube surface
• Generating electron transfers
• Changing CNT charge carrier density (and thus resistance)
Electron donating or withdrawing molecules
Unique Sensing Solution

4. 3
CNT Oil Sensor
- Excellent sensing performance in oil
- Reaction through direct contact with oil ;
Additional equipment not required for extracting gas
and degraded materials
- Low cost due to simplified system
- Secured “Unique Technology for CNT Paste”
- Developed “Low Cost Process Technology”
- “Application Technology” to analyze various oils;
Transformers
Auto vehicles
Edible oils for food
Unique Sensing Solution

5. 4
Outline of Sensing System
TCG
&
Degradation
status
Wire
&
Wireless
Inspection
+
Diagnosis
+
Management
Safety
&
No accidents
Measurement;
Total Combustible Gas(TCG),
Degradation status of
insulation oil using CNT sensor
Integrated monitoring functions
utilizing wire-wireless data
transmission system
Preventing accidents and
securing safety by analyzing
transformer status in a real-
time manner
Enhanced efficiencies facilitating;
Inspection,
Diagnosis,
Management of Transformers
Solutions
Unique Sensing Solution

6. 5
Insulation Oil Degradation
Degradation Phenomena : Thermal degradation by operation in a high temperature
Gas
Unique Sensing Solution
Affecting mechanical
strengths in
substation facilities
Increased
vibrations
Generated
combustible gas
Caused
dielectric breakdown
Accelerated by overload operation

7. 6
Criteria
Unique Sensing Solution
Gases Normal Caution Abnormal Danger
H2 Under 400 401∼800 Over 800 -
C2H2 Under 20 21∼60 61~120 120 or more
C2H4 Under 200 201∼500 Over 500 -
CH4 Under 250 251∼750 Over 750 -
C2H6 Under 350 351∼750 Over 750 -
C3H8 Under 250 251∼750 Over 750 -
TCG Under 1,000 1,001∼2,500 2,501~4,000 4,000 or more
Increased amount
of TCG
- -
Over 2,000ppm/year
from “Caution”
Over 3,000ppm/year
from “Abnormal”
Insulation Oil Degradation
Insulation oil analysis method ;
Judging abnormality by TCG amount and amount of each gas

8. 7
Comparison with other products
Comparison
Div. HYDRAN CALISTO TRUE GAS OTS Series
Manufacturer
GE SYPROTEC
CANADA
MORGAN SCHAFFER
CANADA
SERVERON
USA
SNS Revolution
Korea
Main functions
• To monitor dissolved gas of
transformer insulation oil
• To monitor abnormal gas
and moist of Transformer
• To analyze dissolved gas of
transformer insulation oil
• To analyze degradation of
insulation oil
• To measure dissolved gas of
transformer insulation oil and
degradation
Gas, components
to be monitored
H2,CO,C2H4,C2H2
(composition value of 4 gases)
H2, moist
H2,CO,C2H4,C2H2,
C2H6,CH4,CO2,O2
Detection of total combustible
gas amount in transformer
insulation oil
Analysis method Gas amount H2 gas and moist amount Combustible gas amount
Oil degradation and Combustible
gas amount
Price Expensive Expensive Expensive Inexpensive
Far more competitive in “Price” than competitors’
No “Maintenance & Operation”
“Real-Time” base 24 hours monitoring system
Unique Sensing Solution
Additional equipment not required for extracting gas in oil → saving cost

9. 8
Comparison
Div. HYDRAN CALISTO TRUE GAS OTS Series
Merits
• Instant site monitoring
• Continuous monitoring and
recording major gases
• Monitoring 4 Tr at the same
time
• Site installation type
suitable for monitoring trends
• Easy maintenance
• Analyzing causes of
each pattern
• Site measuring/analysis
possible
• Analyzing various gases
• Easy installation at site
• Integrated diagnosis system
with sensors installed in each Tr
(Max. 255 Trs)
• Additional equipment not
required for extracting gas →
Low cost
• No maintenance & operation
• Tr capacity is not limited ;
Multi applicable for large Tr,
pole Tr, ground Tr
Demerits
• Required equipment to
convert liquid into gas
• Required new column for
replacing or recalibrating due
to residual gas of the
previous analysis
• Required replacing sensor
rather frequently
• Measuring dissolved
gas amount not possible
• Only measuring H2 and moist
• Required skilled analyzer
• Real Time monitoring not
possible
• Expensive equipment
• Lack of data reliability
when analyzing 2 or more
Tr in parallel
• Required site data
accumulation
• Analysis of each gas not
possible (※)
Comparison with other products
(※) According to international regulation, ASTM D 3612, only total combustible gas amount is measured
for analyzing transformer insulation oil status.
Unique Sensing Solution

10. 9
Introduction of system
OTS-1000 / OTS-2000
Major Component
Sensor module body for insulation oil
degradation detection
Materials for installation
Real-time monitoring system
Unique Sensing Solution

11. 10
Introduction of system
Specification
Main Sensor Module
CNT Oil Sensor
Data Transmission parameters
1. Degradation status of insulation oil
2. Total Combustible Gas(TCG) amount
3. Temperature and time
Data transmission
1. Wire or wireless online communication
2. Long-term data accumulation; more than 10 years
3. Diagnosing insulation oil status & alarm
function installed in the system; LED lights
OTS-100 / OTS-2000
Unique Sensing Solution

12. 11
Transformer
System Flow – Transformer oil degradation sensing
Introduction of system
OTS-2000
Unique Sensing Solution

13. 12
Wire/Wireless
Communication
< Web Server >
Users
Internet
< Transformers > < SNS Sensing System >
<OTS-2000>
Type A
Type B
Type C
System Configuration
Introduction of system
<OTS-100>
Unique Sensing Solution

14. 13
Unique Sensing Solution
1. Sensor module / Case
2. Materials for installation
3. Real-time program
Introduction of OTS-2000
Main Sensor Module Cabon Nano Tube(CNT) Oil Sensor
Data transmission factor Time, oil degradation & TCG, temperature
Measured range TCG, accelerated degradation status of insulation oil
Measured gas
TCG: H2, C2H2, C2H4, CH4, C2H6, CO
(based on ASTM D3612 criteria)
Diagnosis method
Diagnosing transformers status by analyzing data patterns measured
(Daily, weekly, monthly, total change amount)
CNT Sensor End Of Line (EOL) 15 years or more
Warranty 3 years
Operation temperature 0 ~ +120 ℃
Operation height 4,000M or less
Size (Width×Height×Depth) 400×500×200mm
Weight 15 ~ 22Kg
Case material STS 304 or AL5005
Case surface treatment Power coating
Oil circulation pump Solenoid pump: 500~700ml/Min.
Oil pipe 3/8" OD copper steel or stainless steel
Length of oil pipe Sucking: 2 ~ 20M, Outflow: 2 ~ 20M
Power 85 ~ 260 VAC, 50 ~ 60 Hz, 350W
Communication RS485, RS232, Ethernet,, Wi-Fi
Data save period 10 years (6 times of diagnosis per a day)
Diagnosis of abnormality Diagnosis function installed for abnormality of sensor, pump, circuit
Software NMS Program
Technical SpecificationConfiguration

15. 14
Integrated System Configuration
Diagnosis program 1 - NMS (Network Management System)
※ General Figure
Transformer Oil Sensing Management SystemLogo
Monitoring
Sensing
Setting
Statistics
Administrator
setting
Notice
Unique Sensing Solution
Abnormal

16. 15
Integrated System Configuration
Diagnosis program 3
Monitoring – Warning ListLogo
Monitoring
- Warning List
- Sensing Result
- Equip. status
Sensing
Setting
Statistics
Administrator setting
Notice
Trans 37
Temp. 58.2℃
Sensor 1 0.0001
Sensor 2 0.0001
Sensor 3 0.0001
Trans 38
Temp. 58.2℃
Sensor 1 0.0001
Sensor 2 0.0001
Sensor 3 0.0001
Trans 39
Temp. 58.2℃
Sensor 1 0.0001
Sensor 2 0.0001
Sensor 3 0.0001
Abnormal : Oxygen factory → Section 4 → Transformer No. 37
Unique Sensing Solution

17. 16
Integrated System Configuration
Diagnosis program 5
Logo
Monitoring
- Warning List
- Sensing Result
- Equip. status
Sensing
Setting
Statistics
Administrator setting
Notice
Abnormal : Oxygen factory → Section 4 → Transformer No. 37 → Abnormal Temp.
Monitoring – Warning List
Trans 37 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Oil OK OK OK OK OK OK OK OK OK OK OK OK OK OK chk chk
Temp. 30 33 34 32 35 36 35 34 33 32 31 30 32 33 35 35
Device OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK
Door CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD CLD
Comm. OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK
Unique Sensing Solution

18. 17
Comparison on test result
between “Analyzed gas value” and
“Measured value by CNT oil sensor”
General
Failures of power transformers are detected through
Analyzing gases in insulation oil, using Gas
Chromatography (GC) equipment.
GC is very expensive and has its limitations in
establishing on-line analyzing net-work.
HOWEVER
To verify reliability of CNT oil sensor by a comparison test between
“Analyzed gas value” and “Measured value by CNT oil sensor
Unique Sensing Solution

19. 18
Test outline
Place
Insulation Gas analysis laboratory of EIC
technology Dept, POSCO Gwangyang Steel Mill
Performed by
EIC technology Dept, POSCO
Smart Grid Team, RIST
SNS R&D
Comparison on test result
between “Analyzed gas value” and
“Measured value by CNT oil sensor”
Unique Sensing Solution

20. 19
Comparison on test result
between “Analyzed gas value” and
“Measured value by CNT oil sensor”
Test result
Reliability of CNT oil sensor module was verified
and confirmed which has reacted accurately
corresponding to change of combustible gases.
※ Refer to Annex 1 Research Institute of Industrial Science & Technology(RIST) test report
Unique Sensing Solution

21. 20
Comparison on test result
between “Analyzed gas value” and
“Measured value by CNT oil sensor”
Conclusion
CNT oil sensor module
Reacting
Detecting
It was confirmed that CNT oil sensor module
employing CNT reacted accurately corresponding to
change in density of combustible gases regardless
of temperature of insulation oil.
It was verified that CNT oil sensor module has
detected total amount of combustible gases
(six kinds of gases, H2, CH4, C2H6, C2H2, C2H4
and CO) and it was thus confirmed that CNT oil
sensor is very effective to diagnose transformer oil
degradation status.
Unique Sensing Solution

22. 21
Comparison on test result
between “Analyzed gas value” and
“Measured value by CNT oil sensor”
Conclusion
Compact system
Easy to monitor and handle
Not expensive
Having advantageous merits in constructing on-line monitoring net work
which can prevent failure accidents of power transformers
Minimizing transformer maintenance costs
It is verified that CNT oil sensor is ;
Unique Sensing Solution

23. Thank You
- End of Document -
22
Unique Sensing Solution

24. 23
Annex 1
RIST Test Reports(1/5)
Unique Sensing Solution

25. 24
Annex 1
RIST Test Reports(2/5)
Unique Sensing Solution

26. 25
Annex 1
RIST Test Reports(3/5)
Unique Sensing Solution

27. 26
Annex 1
RIST Test Reports(4/5)
Unique Sensing Solution

28. 27
Annex 1
RIST Test Reports(5/5)
Unique Sensing Solution

29. 28
Annex 2
Analysis data - Transformer insulation oil
Assessment of CNT oil sensor analysis test
Sensing Rate of CNT Sensor
OxidationStability
[mgKOH/g]
DielectricStrength
[KV]
※ MICHANG OIL IND.CO.,LTD Analysis Data 2008.01
Unique Sensing Solution

30. 29
Annex 2
Analysis – Characteristic of transformer insulation oil
Assessment of CNT oil sensor analysis test
Replacement criteria
(Sensing Value)
Unique Sensing Solution

31. 30
Annex 3 - Insulation Oil Degradation
Components area Degradation phenomenon
Trf
Parts Material Types Impact Indicators
Iron core
Iron core
insulation
Manila paper ,
pressboard
Thermal degradation
Decrease in mechanical strength,
increase in vibration
Occurring variation of noises and
vibrations
Winding wire
Conductor
insulation
Kraft paper
Thermal degradation
Partial discharge
degradation
Pyrolysis of insulating material
1. Decrease in mechanical
strength
┌ Dielectric breakdown
└ Increase in vibration
2. Generation of combustible gas
1. Occurring variation of
dissolved oil gas
2. Decrease in degree of poly-
merization of insulating
paper
3. Decrease in mechanical
strength of insulating paper
Winding wire
insulation
Kraft paper,
pressboard
Coil support
Woods,
pressboard
Lead wire
Conductor
insulation
Kraft paper
Lead support
Woods,
pressboard
Thermal degradation, a
bsorption of partial
discharge degradation
┌Decrease in dielectric strength
└Generation of partial discharge
→Generation of combustible gas→
Dielectric breakdown
1. Dielectric breakdown
voltage
2. Variation of oil gas
3. Increase in moisture in oil
4. Dielectric breakdown
voltage
5. Variation of acid value
Insulation oil
Electric
insulation oil
On-load
tab changer
Insulation oil
Electric
insulation oil
Contact
Copper, Copper
alloy
Abrasion,
corrosion
(copper sulfide)
Damage to contact surface
Increase in contact resistance
Overheating and melting loss
1. Number of change-over
2. Contact resistance
3. Contact status
4. Operating torque
Insulation oil-filled transformers
Unique Sensing Solution

32. 31
Increase of transformer temperature
Increase of temperatures in transformer and cooling system
Winding
wires
Iron cores
Heat generated from
iron cores and winding
wires by no-load or
load losses when
transformers are operated
Difference between
ambient and the
transformer temperature
is defined as increase of
transformer temperature
In case of oil-filled
transformers, generated
heat is emitted through
insulation oil
Unique Sensing Solution
Annex 3 - Insulation Oil Degradation

33. 32
Gases generated in abnormal status
Abnormal phenomena Major gases
Overheated
insulation oil
Low temperature
(Over 300℃)
Ethane(C2H6), Methane(CH4), Ethylene(C2H4)
Middle temperature
(300~700℃)
Methane(CH4), Ethylene(C2H4), Ethane(C2H6)
High temperature
(Over 700℃)
Ethylene(C2H4), Methane(CH4), Ethane(C2H6)
Overheated solid insulator
(Over 200℃)
Carbon monoxide(CO), Carbon dioxide(CO2), Methane(CH4)
ARC during insulation
(Over 1,000℃)
Acetylene(C2H2), Hydrogen(H2), Ethylene(C2H4),
Methane(CH4)
CORONA during insulation
(Over 1,000℃)
Hydrogen(H2), Acetylene(C2H2), Ethylene(C2H4),
Methane(CH4)
Degradation of insulation materials and insulation
oil
Carbon dioxide(CO2), Carbon monoxide(CO)
Carefulness is required when even tiny amount of Acetylene(C2H2) is
detected as it is the gas generated by pyrolysis such as arc and discharge
and it thus makes a drastic development of degradation
Unique Sensing Solution
Annex 3 - Insulation Oil Degradation

34. 33
Type of gases in abnormality transformer
Transformers
Solid insulator
Insulation oil
Carbon
monoxide/
Carbon dioxide
Acetylene/
A lot of Hydrogen
Methane/
Ethane/
Ethylene
Dielectric breakdown of solid
insulator caused by abnormality of
coil and lead wire
• Arc, corona between
conductors
• Discharge from sharp edge of
high voltage zone
• Overheating at bare conductor
• Hot spot caused by mal-
connection at joints
Craft insulating paper,
Press Board etc.
200℃
200~800℃
Over
1,000℃
Decomposition by natural degradation under 100℃
Unique Sensing Solution
Annex 3 - Insulation Oil Degradation

35. 34
Annex 4
GE energy data - Trf. oil degradation detection
Source : Power Transformer Life Extension Through Better Monitoring, GE Energy
Real Time Monitoring of
Thermal Degradation
• Reduce Power Outages :
Quality power supply
• Accident Prevention
→ reduce economic losses
• Efficient system maintenance
Unique Sensing Solution

36. 35
Estimate annual values from
monitoring system
$ 38,325 -$ 16,590 = $21,735.
※ Estimated losses by a damaged
transformer
Losses without proper
monitoring system: $38,325
(100%)
Losses with proper
monitoring system installed:
$16,590 (43%)
Source : Power Transformer Life Extension Through Better Monitoring, GE Energy
Unique Sensing Solution
Annex 4
GE energy data - Trf. oil degradation detection