Test de rigidez dielectrica para aceites de transformadores

1. 1
Dielectric Oil Test Set Family
Model OTS

2. 2
Agenda for Discussion
Applications
Customers
OTS Product Range Improvements
Customer Common Key Issues
Customer Issues Resolved by OTS
Key Features
OTS Configured to Order

3. 3
What is the test looking for?
Aging and / or oil contamination by changes in…
• Electrical properties
–Moisture content
–Chemical contamination
–Solids & particles
Change in conditions inside apparatus due to..
• Arcing
• Overheating
• Vibration

4. 4
How is the Test Performed
The test involves application of a rising voltage (at a set rate
of rise) across a specially shaped brass electrodes within a
container of a specific volume.
For specific standards, the oil is circulated within the container
– to replicate convection seen in oil within transformers.
The test is repeated for a pre-determined number of times,
waiting between tests and averaging the results.
The pass/fail is pre-dermined for specific international
standards, and differs for different customers.
Electrodes used within different standards

5. 5
Why test the oil breakdown voltage?
A quick and easy test for equipment in service for:
• Detecting oil moisture and contaminant content before
catastrophic failure
• Predicting remaining transformer life
• Maintaining equipment safety
• Fire prevention
• Maintaining reliability
Checking new oil prior to filling new equipment
Acceptance of new oil deliveries
• Bulk oil shipments
• Separate drum filling of small tank
• Re-processing of used oil

6. 6
Applications
Testing dielectric strength of oil used in:
• Super-grid transformers in Transmission systems
• Distribution transformers at Regional Electrical sites
• Regulating transformers
• Instrument transformers
• Reactors
• Circuit breakers
• Cables
• Bushings
• Capacitors

7. 7
What does the oil do?
Used as an insulation medium
Cooling by circulation

8. 8
Customers
Utility contractors
• Substations mainly
Power Utilities
• Power Stations mainly
Service Provider
Rail Companies
• Including locomotive HV step down transformers and switchgear
Oil test Lab / House / Company
• Providing testing service to all of the above
Transformer / switchgear Manufacturer (OEM)
Oil companies
• Testing new oil during manufacturing

9. 9
Product Range Changes
Megger Old Range
• Laboratory instruments
– OTS60AF/2
– OTS80AF/2
– OTS100AF/2
• Portable instruments
– OTS60PB
– OTS60SX
Megger New Range
• Laboratory instruments
– OTS60AF
– OTS80AF
– OTS100AF
• Portable instruments
– OTS80PB
– OTS60PB
– OTS60SX Continues

10. 10
Customer Common Key Issues
1. Too heavy/bulky for field use
2. “Oil testing is a messy business”
3. Unreliable results
4. Standard testing is complex
5. Instrument is too fragile
6. Ease of test result recording and reporting
7. Ownership costs
8. Change of test standards

11. 11
1. Heavy to carry (portable use)
New Portable Units Lightest in the World
• OTS60PB from only 15.38 kg
• OTS80PB from only 19.48 kg
Important Health and Safety issue
Even the OTS100AF from only 29.58kg
New ergonomic integral side handles
• Provides natural lifting position

12. 12
1. Heavy to carry (portable use)
Visual size / weight differences
OTS80PB OTS60PBOTS60AF OTS80AF OTS100AF
From
65 lb
From
42.9 lb
From
33.9 lb
Laboratory unit Portable unit Portable unit

13. 13
1. Heavy to carry (portable use) - cont
Optional padded carry bag for portable units
Optional transport case for portable units

14. 14
2. “Oil testing is a messy business”
All OTS range share common test vessel featuring:
• Unique easy pour spout
• Unique easy clean shape

15. 15
2. “Oil testing is a messy business” ……continued
OTS have unique test chamber drain
• Easy removal of accidentally spilt oil
• Pipe located on rear of instrument
• Could be plumbed into laboratory waste oil system

16. 16
2. “Oil testing is a messy business” ……continued
Unique test chamber design shaped for easy clean
• No sharp edges or contours

17. 17
2. “Oil testing is a messy business” ……continued
ASTM D1816 testing
Fill oil to level mark and fit impeller lid
Baffle excludes air without displacing oil from vessel
No mess, baffle
sits on oil

18. 18
3. Reliable test results
Precision electrode gap adjustment
• Quick and easy to adjust
Unique electrode gap locking mechanism
• Prevents gaps moving through handling
• Prevent accidentally moving adjustment
• New accurate and smooth gap gauges
Precision thumb wheel
electrode gap adjustment
Gap is then locked with unique
mechanism
Precision thumb wheel
electrode gap adjustment
Gap is then locked with unique
mechanism

19. 19
3. Reliable test results …..continued
Transformer Design
• Limit dissipated power in arc
• Reliability, more rugged
Direct Output Breakdown Detection
• Improved accuracy
• High speed disconnection time
Breakdown detection both in terms of current and
voltage
• Compliance with ASTM and IEC requirements

20. 20
3. Reliable test results …..continued
Optional new voltage calibration meter VCMD100
• Not oil filled so no leaks
• Highly visible LED display
• Digital for ease of reading
• Confidence in results
Built in automatic temperature measurement
• Auto recorded on all test results
• Standards specify temperature of sample
• E.g. IEC require 20 ºC ± 5 ºC

21. 21
4. Standard Testing is too Complex
OTS Portable user interface
Clear colour display
Easy navigation keys
Intuitive menu system
OTS Laboratory user interface
Additional keys for easy data entry

22. 22
5. Instrument is too fragile
Internal transformers and
components able to handle
rugged transport
Extremely strong
Polycarbonate display and
chamber lid
Large impact absorbing
corner mounted rubber feet
Impact and chemical
resistant plastic test vessels

23. 23
5. Instruments are too fragile - cont
Tough chemical resistant key pads
Optional transport case for portable units
Optional padded carry bag for portable units

24. 24
6. Test result recording and reporting
Test results are saved to:
• Internal memory
• USB stick
– Saves carrying the portable instrument into the office
• or a print out
All at the press of a button
Can accommodate up to 10 breakdowns
Bar Code Scanner – fast automated results
Scrolled down
on display

25. 25
6. Ease of test result recording and reporting
…….continued
All OTS AF* come with PowerDB Lite as standard
• Quickly produce professional report forms
All new OTS PowerDB
compatible
* OTS PB TBA

26. 26
7. High Cost of Ownership
More robust design means less likely to be in the
repair shop, less transport cost to and from repair
shop, more trusted results
High quality, built to last, no need to replace for
many years to come.
New breakdown tolerances and voltage accuracy
means less doubt in results, and faster
testing when readings are questioned.
Low cost additional or replacement
test vessels.

27. 27
8. Change to Test Standards
Preloaded standards can be updated via
a USB memory stick
New standards can be updated via a
USB memory stick
Users can produce new custom tests by
adding new or modifying an existing one
and saving to new test name
New or amended standards may be
downloaded from www.megger.com

28. 28
CONCLUSION - Key Features
1. Lightest portable (PB) models in market
2. Precision test vessel with lockable electrode
gap setting
3. Transfer of results via USB flash drive plus
updating new test standards
4. Ultra fast (< 10 μs) HV switch off time –
Consistent results
5. USB barcode scanner (AF only)
6. All new OTS share common accessories
7. VCM100D / VCM80D check meter (option)
8. Automatic oil temperature sensing
9. Sunlight readable colour display and intuitive
user interface

29. 29
New OTS Configured to Order
Flexible order options to suit customer
requirements and / or budget
Order code configuration determined on Data sheet
OTS60PB OTS80PB OTS60AF OTS80AF OTS100AF
Configured items Options
Built in
Not fitted
NiMH (light weight)
Lead Acid (low cost)
Mains supply only
UK plug fitted
EU Schuko plug fitted
US plug fitted
Australian plug fitted
No plug fitted
Supplied
Not Supplied
ASTM (cylindrical and mushroom)
IEC (Spherical and mushroom)
Full set (ASTM and IEC)
Supplied
Not Supplied
Electrode set (shape) supplied
Carry case
Battery
Mains / Line supply lead
Printer
Vessel lid mounted impeller stirrer