Ultrasound technology can be used to proactively detect abnormalities in ring main units (RMUs) by analyzing the ultrasonic sound patterns produced during faults. This allows identification and prevention of failures before they become critical, avoiding SF6 gas leakage which contributes to global warming. A technology was developed using ultrasound sensors to detect corona, tracking, and arcing in RMUs based on their unique ultrasonic frequencies and intensities. Applying this technology from 2012-2016 identified abnormal RMUs, prevented over 750 failures, and avoided the release of 0.05 million metric tons of carbon dioxide equivalent of SF6 gas into the atmosphere. An app was also created for centralized data recording and management to further optimize inspections and reduce carbon emissions

1. GHG EMISSION CONTROL- A
PROACTIVE ELECTRICAL ASSET
MANAGEMENT THROUGH
ULTRASOUND TECHNOLOGY
Event/Meeting
Date & Venue

2. 2
Problem Definition
RMU Flashover SF6 Gas Leakage
High Revenue Losses
due to R&M Cost
Unsafe Working
Environment
High Down
Time
Customer
dissatisfaction

3. 3
Present technology not sufficient to prevent RMUs failure and gas leakage
SF6 gas Leakage from RMUs adding to Global warming
Switch Gears produce sound before the abnormality becomes critical
Sound is produced due to ionization which in infant stage is in
Ultrasound region and the sound is variable
Corresponding to the sound, there must be a pattern as well
Analysis of the wave pattern produced due to ionization can be used to
identify the nature of fault and the criticality
Outcome of Analysis
Need of a Technology:
Proactively Detects the Abnormality in the RMUs
Fix the Gas Leakage Problem

4.  They are more directional and travel in a straight line.
 Localized to the source of emission.
Discharges in Power system that generally produce
Ultrasonic Frequency:
Characteristic Phenomena
Arcing
Tracking
Corona
Not possible to
capture at the
initial stage
Not possible to
detect by other
methods like
Infrared Scanning
No standard
guideline
4

5. CORONA IDENTIFICATION
• Hissing Noise
• Uniform peaks at equal
intervals of time
• Frequency domain pattern
has harmonics of the line
frequency and they are
visible in its pattern
• Corona discharge happens
at the peak of the cycle
• Corona discharge produces
ozone and nitrous oxide
5

6. • Low current pathway from
top to ground through the
insulator.
• Can happen anywhere in
the positive cycle.
• Harmonics are not
present.
• Less uniformity in
pattern and popping
sound occurs.
• Advantage: Identification
at this stage can prevent
the switch gear failure
TRACKING IDENTIFICATION
6

7. • High Current pathway
from top to ground
through insulator which
don’t even require high
voltage.
• It is quick and abrupt
with buzzing sound.
• Burst of Energy
extending for large
periods of time.
• Most random pattern so
it is easily recognizable.
ARCING IDENTIFICATION
7

8. 8
1845
240
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2012-2013
No. of RMUs Scanned
No. of RMU Failed
Global and Local Impact
 Greenhouse gas leads to Global
Warming
 Amount of SF6 Gas in each RMU
breaker chamber= 3 Kg
 Global Warming Potential of SF6 gas=
23900
 For a Failure of one RMU, SF6 Gas
escaped= (23900*10-9 *3=) 0.0000717
Million Metric Tons of Carbon-di-Oxide
Equivalent (MMTCDE).
In 2012-2013, 240 Nos. of RMUs failed
resulting into the escaping of SF6 gas
equivalent to
(0.0000717*240=) 0.017208MMTCDE

9. 9
Ultrasound Scanning
Abnormality Frequency(Hz) Intensity
Corona
50,100,150,200,25
0,300,350…all
harmonics
Between -8.0
dBμV to -5
dBμV
Tracking 50,100,150,200.
Between -5.0
dBμV to -2.0
dBμV
Arcing
No component of
Line Frequency
Greater than -
2.0 dBμV

10. 10
Proactive SF6 Gas Leakage Detection and Fixing
 Proactive SF6 gas Leakage
Detection in the Switch Gears
is done using a gas leakage
detector.
 Leakage points are marked for
further action.
 Unique compound consisting of
poly chlorides is used as
corrective action for the leakage
points identified
 Refurbishment of 5 nos. of
breaker chambers that have
even exploded using the unique
compound thus reusing and
revenue saving is also ensured
GAS
Leakage
Detector

11. 11
No. of
RMUs
Scanned
Abnormal
RMUs
RMUs
Failed
RMUs
Saved
SF6 Escaped/
Prevented
(MMTCDE)
2012-
2013
1845 NA 240 0 0.0172080
2013-
2014
2200 238 30 208 0.0149136
2014-
2015
2565 250 14 236 0.0169212
2015-
2016
3200 268 7 261 0.0187137
SF6 Gas Escaped Into Atmosphere
SF6 Gas Prevented From Escaping
Into Atmosphere
Curtailed SF6 Gas Emission
 Ultrasound Technology accompanied
with Gas Leakage Detection have
made it possible to diagnose Switch
Gears in a way like a Doctor diagnoses
patients
 From 2013-14 to 2015-16, around 750
nos. of RMUs have been prevented
from failure accounting to stopping of
0.05 MMTCDE from escaping into the
environment which is around 2% of
GHG emitted in India per year

12. 12
Another Step: App for Carbon Reduction
 Man-Hour Optimization
 Earlier 20 Switch Gears Inspected
per day
Now 30 to 35 Switch gears are
Scanned per day using the App.
 For Scanning the same number
of switch gears, number of
vehicle based trips reduced by
50% reducing carbon emission.
 Centralized Data Record Center
 Earlier paper was used to record
data on site.
Now data recording through app has
quashed the use of Paper.
 Scanning Data is available to
everybody at all the time
without using paper.

13. Thank You