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COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
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1. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
RESEARCH ARTICLE
OPEN ACCESS
A measurement technique to identify and locate partial discharge
in transformer with AE and HFCT
Urairat Fuangsoongnern1, 2, Asst. Prof. Dr.Winai Plueksawan2
1
2
Provincial Electricity Authority, Bangkok, Thailand
Faculty of Engineering Kasetsart University, Bangkok, Thailand
ABSTRACT
This paper proposes a measurement technique to identify and locate the occurrence of partial discharge (PD) in
the insulation of oil immersed and dry type distribution transformers. With reference to IEEE Std. C57.1272007, four acoustic transducers type PD-TP500A were used to locate PD and one HFCT (High frequency current
transducer) was used to identify PD. This process could accurately identify and locate the source of PD
occurring at any position in a distribution transformer. The result of the findings enabled us to prevent damage
and deploy defensive maintenance measure on the distribution transformer in time.
Keywords - Partial Discharge, Oil Type Transformer, Dry Type Transformer, Acoustic Emission, High
Frequency Current Transducer
I.
Introduction
Transformer is the main equipment which
used to modify the voltage in the high voltage from
one level to another level in order to supply electricity
through transmission lines or distribution lines.
Transformers are used for 24 hours and transformers
could be damaged by the PD occurring. The research
is intended to detect PD in distribution transformers
by measuring the PD and identify PD. The measured
signal is the waveform shown through computer
screen. Bring up the waveform and locate the source
of PD occurring at any position in a distribution
transformer to analyses for planning in order to
prevent damage and preparing to maintenance
distribution transformers to prevent damage in
distribution transformers.
II.
Components Of The Transformer
Most of the structure of the transformer
consists of 3 major components: Core: iron core of a
transformer is made from metal sheets, coated with
dielectric laminate. Material of dielectric laminate,
made from Ferromagnetic, has good magnetic
properties. The high magnetic permeability help
reducing the magnetic leakage phenomena.
Winding: Conducting coil of a transformer is
generally made of copper or aluminum wire, wrapped
with insulation.
Insulation: the insulation of transformer is intended to
prevent winding’s exposure to the core steel and
prevent each turn of coils from touching one another.
In general, transformer consists of two types.
Oil Immersed Transformer consists of winding, core,
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insulation oil, tank, HV bushing, LV bushing and oil
level gauge. Mineral oil is used as insulation and
cooling.
Dry Type Transformer consists of winding, core,
connector and cooling fan. Resin is used as insulation
III.
Causes And Effects Of Transformer
Damage
The major cause of transformer insulation
deterioration and damage is caused by Partial
Discharge (PD). The insulation of the electrode, one
side or both sides may be a solid, liquid or gas. Partial
discharge occurs in the insulation. With a high electric
field is not uniform or insulation is not uniform or
homogeneous or other contaminating. Electric field
stress at some point in the insulation is higher than the
critical electric field stress. But may not have caused a
complete breakdown. But it only partially [1, 2, 3, 4, 5].
IV.
Theory Of The Measurements,
Identification And Location Of The
Occurrence Of Partial Discharge
Measurement techniques and analysis signal
can be divided into the two modes:
Off-line Monitoring: Off Line Monitoring Partial
Discharge measurement is being measured when all
the devices stop working (Shut down system).
On-line Monitoring: On Line Monitoring Partial
Discharge measurement is conducted while all the
devices are operating normally and being nonstop
working. In the measurement of the partial discharge
in this mode, the Partial Discharge occurs while
supply being on only [6].
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2. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
In this article, the researchers measured the PD in the
transformers using the On-line Monitoring described in
AE method (Acoustic Emission: IEEE Std. C57.1272007) [9] and HFCT (High Frequency Current
Transducer).
4.1
Acoustic Emission technique
Acoustic Emission technique is testing by sending
sound waves through an advanced non-destructive
testing [7, 8]. The principle is to measure the frequency
and the energy released when the crack expansion or
when the phase change in the material and the energy
that is released from the physical change in a solid
material. Caused by external force or by a change in
temperature such as the fluid and within the crack.
Which the object is detected by the release of energy
and precise to predict the position of the Partial
Discharge [9, 10, 11].
can be viewed in trend, table view, 2D graph, 3D
graphic and amplitude-pulse.
5.2
Description of equipment used in the test
5.2.1PD-TP500A
PD-TP500A is a tool which is used for analysing
signal and the findings signal of partial discharge of
equipment. PD-TP500A has five channels consist of
four of AE (Acoustic Emission) and a HFCT (High
Frequency Current Transducer) sensors detecting the
signal simultaneously, compare the signals to
determine whether the signal originated from inside of
the equipment or outside. When comparing all four
signals from AE sensors, the location of the source
can be determined.
Figure 2. Power PD System Model (PD-TP500A)
Figure 1. Illustration of typical propagation paths for
the acoustic PD signal
4.2
High Frequency Current Transducer technique
High Frequency Current Transducer technique has
been specifically designed to measure the signal of
Partial Discharge in contrast, it has a ferrite core to be
suitable for the device to be measured. The main
applications in the measurement the signal of Partial
Discharge devices use HFCT consistent with ground
wire of the transformer. Partial discharge test with
HFCT on line transfer impedance measurement
method is a technique in which units of measure are in
the form 2.4 mV/1mA.
V.
5.2.2 AE Sensor
AE Sensor (Type R15I: Preamplifier 100x) has a
sensitivity of 20 pC. Frequency range is from 50 kHz
to 300 kHz. The sampling rate is 18 MHz. (max). The
detected signals will be amplified 100 times for
further processing.
Figure 3. AE Sensor
5.2.3 HFCT Sensor
HFCT Sensor (Type 50/100: 1mA/2.4mV) has a
sensitivity of 5 pC. Frequency range is from 100 kHz. to
30 MHz. The sampling rate is 20 MHz (max). The signal
rate is one to 2.4.
The Equipments Used In The
Experiment
5.1
Partial Discharge Signal Analysis is online
The device which used to display on the computer
screen called Power PD (PD-TP500A). It used for
measuring the Partial Discharge online for
transformers with Sensors 2 types of AE Sensor and
HFCT Sensor is connected to the PD-TP500A via
coaxial cable at a distance of 20 meters and connected
to HFCT at a distance of 10 meters. The signals from
four AE sensors and a HFCT are measured
simultaneously and the data is saved in computer [12].
The software will analyze the frequency of measured
signal, burst time, spectrum and the location of the
source [13]. The data from the continuous monitoring
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Figure 4. HFCT Sensor
5.3
Preparation for the test
Equipment used in testing are:
5.3.1 AC power source
5.3.2 Sets of equipment PD-TP500A consists of AE
Sensor and HFCT Sensor and computer to display the
measurement and analysis of the signal Partial
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3. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
Discharge by connection Power PD (PD-TP500A) to
computer via Port USB.
5.3.3 Equipment used to measure the partial discharge
signal must be loading and running at all times.
5.3.4 When the equipment provided and installed to
measure signal of partial discharge completed and
then performed to detect and measure the signal. The
result of signal to analysis and locate the source of the
signal detected.
If none of the sensors were able to detect any signals
of PD Burst, it could be concluded that no PD
occurred within the transformer, as shown in Figure 8.
Figure 8. Display of No Partial Discharge
Figure 5. Configuration of PD-TP500A
VI.
Reading Data And Signals Attained
From The
Experiment
If signals were detected by AE sensors only, it could
be concluded that the signals could either be a
mechanical signal, floor vibration or some sort of
loose parts inside the transformer, as shown in Figure
9, Figure 10, and Figure 11 respectively.
Figure 6. Display of Software
If PD Burst were detected from both AE sensors and
HFCT sensor. It could be concluded that the PD
occurred within the transformer, as shown in Figure 7.
Figure 7. Display of Partial Discharge Detect
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Figure 9. Display of a Mechanical Signal inside
the transformer
Figure 10. Display of Arcing signal inside the
transformer
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4. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
Figure 13. The position of AE sensor installation for
Oil Immersed Transformer (Core Form: Single Phase)
Figure 11. Display of Signal from inside of core
vibration
If signals were detected from the HFCT sensor only, it
could be concluded that the signals could be
mechanical signals or from arcing inside the
transformer or it could be signals of PD caused by
external transformer as shown in Figure 12.
Figure 14. The position of AE sensor installation for
Oil Immersed Transformer (Core Form: Three Phase)
Figure 15. The position of AE sensor installation for
Oil Immersed Transformer (Shell Form: Single Phase)
Figure 12. Display of Partial Discharge outside
the transformer
VII.
The Installation of AE Sensors And
HFCT Sensor
The installation of AE sensors referred to the
IEEE Std C57.127-2007, Guide for the Detection and
Location of Acoustic Emissions from Partial
Discharge in Oil-Immersed Transformers and
Reactors [9, 14, 15, 16]. AE 1: Installed at Top of
Side 1 (HV Side), AE 2: Installed at Bottom of Side 2
(Left Side), AE 3: Installed at Top of Side 3 (LV
Side) and AE 4: Installed at Bottom of Side 4 (Right
Side)
Figure 16. The position of AE sensor installation for
Dry Type Transformer
VIII.
Case Study
8.1
Oil Immersed Transformer
The experiment was conducted on May 31, 2011. The
transformer being tested was an Oil Immersed Type
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5. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
with specifications of 2000 kVA, 22 kV/400-230 V,
50 Hz,3 Phases. The position of AE sensor installation
referred to IEEE Std C57.127-2007 [9].
Figure 20. The result of measured signal of PD
(Move AE and HFCT)
Figure 17. The position of AE sensor and HFCT
on transformer
Figure 18. Signal of partial discharge detection
with AE and HFCT
As shown in Figure 20, after reposition the sensor 2,
sensor 3, sensor 4 and HFCT, the PD location at
sensor 1 could be confirmed. In order to reconfirm the
PD location, all the AE sensors were repositioned
along Y axis (vertical) and HFCT remained on case
ground of side 2.
Figure 21. The position of AE sensor and HFCT
after repositioning
Figure 18 shows the signals detection from AE sensor
1 and HFCT sensor. To confirm the location of PD,
sensor 2, sensor 3 and sensor 4 were repositioned
around sensor 1 and HFCT was moved to the position
of on case ground of side 2.
Figure 22. The result of measured signals of PD
(AE sensors and HFCT repositioned)
Figure 19. Position of AE sensors and HFCT
on transformer
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From Figure 22, after the AE sensors were installed
along the Y axis, it could once again be confirmed
that the PD occurred at the location of AE sensor 1.
To make another reconfirmation, all the AE sensors
were moved to the position of the top of side 1 while
the HFCT remained at the same position.
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ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
Figure 23. The position of AE sensor and HFCT on
transformer (After knowing the source of the signal)
Figure 26. Signal of partial discharge detection
with AE and HFCT
From Figure 26, show the signal detection from AE
sensors and HFCT. In order to reconfirm the PD
location, all the AE sensors were repositioned along X
axis (horizontal) and HFCT remained on case ground
of side 4 as shown in Figure 27.
Figure 24. The result of measured signal of PD
(after AE sensors and HFCT repositioned)
Figure 24, shows that the AE sensors and HFCT sensor
were able to detect and locate the PD at the position of
the top of side 1. The positions of the AE sensors are
shown in Figure 23.
8.2
Dry Type Transformer
The experiment was conducted on November 12, 2010.
The transformer being tested was a Dry Type Transformer
with specifications of 1600 kVA, 24 kV/400-230V, 50
Hz, 3 Phases. The position of AE sensor installation
referred to IEEE Std C57.127-2007 [9].
Figure 25. The position of AE and HFCT on
Dry Type Transformer
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Figure 27. The position of AE sensor and HFCT
after repositioning
Figure 28. The result of measured signals of PD
(AE sensors and HFCT repositioned)
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7. Urairat Fuangsoongnern et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
From Figure 28, after the AE sensors were installed
along the X axis, it could once again be confirmed that
the PD occurred at the location of AE sensor 2. To make
another reconfirmation, all the AE sensors were
repositioned along Y axis (vertical) while the HFCT
remained at the same position as shown in Figure 29.
Figure 32. The result of measured signal of PD
(after AE sensors and HFCT repositioned)
Figure 29. The position of AE sensor and HFCT
after repositioning
From Figure 32, shows that the AE sensors and HFCT
sensor were able to detect and locate the PD at the
position of the top and middle of side 3. The positions
of the AE sensors are shown in Figure 31.
IX.
Figure 30. The result of measured signal of PD
(after AE sensors and HFCT repositioned)
From Figure 30, after the AE sensors were installed
along the Y axis, it could once again be confirmed
that the PD occurred at the location of AE sensor 2.
To make another reconfirmation, all the AE sensors
were moved to the position of the top and middle of
side 3 while the HFCT remained at the same position.
X.
Figure 31. The position of AE sensor and HFCT on
transformer (After knowing the source of the signal)
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Conclusion
From the measurement of partial discharge in
oil immersed transformer and dry type transformer
with on-line monitoring methodology using the PDTP500A in conjunction with acoustic emission (AE)
sensors (reference to IEEE Std. C57.127-2007) and a
clamp-on type high frequency current transducer
(HFCT) to detect and locate PD, it could be
summarized as follow.
9.2
The equipments used for PD measurement,
which are the PD-TP500A, AE sensors and HFCT,
can be installed at the equipment being measured
while it is running, no need to shut down the
equipment and the power system.
9.3
This set of equipments is able to detect and
analyze the problems occurring inside the transformer
in the early state and inform how severe the problem
is. More importantly, it is able to indicate whether the
problem is caused by partial discharge, mechanical
problems, arcing or loose part inside the transformer.
9.4
This method of partial discharge diagnosis is
able to detect and correctly locate the partial discharge
occurring inside the transformer which helps the
transformer maintenance to be carried out effectively
and then prevents the complete breakdown of the
transformer which eventually reduces the cost
occurring from repairing severely damaged
transforme.
Acknowledgments
I would like to express my sincere thanks to
my thesis advisor, Asst. Prof. Dr.Winai Plueksawan
for her invaluable help and constant encouragement
throughout the course of this research. Finally, I most
gratefully acknowledge my parents and my friends for
all their support throughout the period of this
research.
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ISSN : 2248-9622, Vol. 4, Issue 2( Version 5), February 2014, pp.51-58
REFERENCES
Urairat Fuangsoongnern, Winai Plueksawan,
and Promsak Apiratikul, Partial Discharge
Analysis for Power Distribution Transformer
Model, The Proceeding of 46th Kasetsart
University Annual Conference, January 29 –
February 1, 2008, 72-80.
[2] F.H. Kreuger, Partial Discharge Detection
in High-Voltage Equipment, Butterworths,
London, England,1989.
[3] H. Ogihara, Detection and location of
coronas in oil-immersed transformer with
corona detector. Electr. Eng. Jpn., vol. 84,
1964, 12-22.
[4] S. A. Boggs, Partial discharge-Part III:
Cavity-induced PD in solid dielectrics.
IEEE Electr. Insul. Mag., vol. 6, no. 1,
Jan./Feb. 1990, 11-20.
[5] Winai Plueksawan, Promsak Apiratikul,
and Urairat Fuangsoongnern, Partial
Discharge Analysis for Power Distribution
Transformer Model. EECON-31. 31st
Electrical
Engineering
Conference,
October 29-31, 2008, 299-302.
[6] A. Santosh Kumar, Dr. R.P. Gupta, Dr. K.
Udayakumar, and A. Venkatasami, Online
Partial Discharge Detection and Location
Techniques for Condition Monitoring of
Power Transformers: A Review. IEEE
International Conference on Condition
Monitoring and Diagnosis, Beijing, China,
April 21-24, 2008, 927-931.
[7] R. T. Harold, Acoustical technology
applications in electrical insulation and
dielectrics. IEEE Trans. Electr. Insul., vol.
20, no. EI-1, Feb. 1985, 1-3.
[8] B. R. Varlow, D. W. Auckland, and C. D.
Smith, Acoustic emission analysis of high
voltage insulation. IEE Proc.-Sci. Meas.
Technol., vol. 146, no. 5, 1999.
[9] IEEE Guide for the Detection and Location
of Acoustic Emissions from Partial Discharge
in Oil-Immersed Power Transformers and
Reactors. IEEE Std. C57.127-2007.
[10] IEEE Guide for Partial Discharge–Part
XIV: Acoustic partial discharge detection–
Practical application. IEEE Electr. Insul.
Mag., vol. 8, no.1, Jan./Feb. 1992, 34-43.
[11] IEEE Guide for Partial Discharge – Part XIII:
Acoustic partial discharge detection –
Fundamental considerations. IEEE Electr.
Insul. Mag., vol. 8, no.1, Jan./Feb. 1992, 2531.
[12] Prasanta Kundu, N. K. Kishore, and A. K.
Sinha, Simulation and Analysis of Acoustic
Wave Propagation due to Partial Discharge
Activity. IEEE 2006 Annual Report
Conference on Electrical Insulation and
Dielectric Phenomena, 607-610.
[1]
www.ijera.com
[13] R. T. Harold, Acoustical waveguide for
sensing and locating electrical discharge
in high voltage power transformers and
other apparatus. IEEE Trans. Power App.
Syst., vol. PAS-98, no. 2, 1979, 449-457.
[14] Xiaodong Wang, Baoqing Li, Harry T.
Roman, Onofrio L. Russo, Ken Chin, and
Kenneth R. Farmer, Acousto-optical PD
Detection for Transformer. IEEE Transactions
on Power Delivery, Vol. 21, July 3, 2006,
1068-1073.
[15] Su Su Win, Myo Myint Aung, and Wunna
Swe, Partial Discharge Detection and
Localization in Power Transformers. The
8th Electrical Engineering/ Electronics,
Computer,
Telecommunications
and
Information Technology (ECTI) Association of
Thailand Conference, 2011, 673-676.
[16] A. K. Lazarevich, Partial Discharge
Detection and Localization in High Voltage
Transformer using an Optical Acoustic
Sensor. Master of Science Thesis, The
Virginia Polytechnic Institute and State
University, USA, 2003.
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