Research Article Design of a UHF Antenna for Partial Discharge … · 2020. 1. 13. · arm...

Research ArticleDesign of a UHF Antenna for Partial Discharge Detection ofPower Equipment

Youyuan Wang Junfeng Wu Weigen Chen and Yajun Wang

State Key Laboratory of Power Transmission Equipment amp System Safety and New Technology Chongqing UniversityChongqing 400044 China

Correspondence should be addressed to Youyuan Wang 1028456357qqcom

Received 23 July 2014 Revised 25 September 2014 Accepted 29 September 2014 Published 15 October 2014

Academic Editor Tao Zhu

Copyright copy 2014 Youyuan Wang et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A single-armArchimedean spiral antenna that can be directly fed by a 50Ω coaxial cable is investigated in this study Every antennaparameter is optimized under simulation to make the antenna work in the ultra-high frequency band The influence of dielectricmaterials feed cone angle and antenna duty ratio is also examined Partial discharge (PD) experiments on several typical artificialinsulation defects are conducted and a single-arm Archimedean spiral antenna and a typical microstrip antenna are utilized forPD measurement The PD characteristics of different insulation defects are also analyzed Results show that the designed antennais suitable for ultra-high frequency monitoring The detection sensitivity of the single-arm spiral antenna is superior to that of theordinary microstrip antenna The former can be utilized in wide-band measurement fields

1 Introduction

Partial discharge (PD) detection has been applied extensivelyin transformer fault diagnosis and online monitoring Latentinsulation faults in transformers can be determined effec-tively through PD detection Early studies have shown thatthe increase time of the PD pulse generated in transformer oilis very short and the pulse width is at the nanosecond levelThus the electromagnetic signal caused by the PD pulsecan contain the ultra-high frequency (UHF) band The UHFsignal is extracted individually to reduce the influence ofnoise on the PD signal The frequency band of commonelectromagnetic interference is not in the range of the UHFband thus eliminating the interference through UHF detec-tion is feasible Reference [1] has demonstrated the feasibilityof using the Archimedean spiral antenna to detect theUHF partial discharge signal emitted from power transform-ers Several experiments have also been designed to studyantenna performance International scholars have conducteda series of studies on the Archimedean spiral antenna Thesize of the Archimedean spiral antenna is reduced bychanging the shape of the antenna arms or performingseveral complex loading techniques at the feed terminal

the antennarsquos performance at low frequency is improvedsimultaneously according to [2ndash6] The radiation character-istic of the antenna is changed by transforming the overallstructure of the antenna according [7 8]

However all of the Archimedean spiral antennas referredto above cannot eliminate the restraint of the feed balun inwhich the structure increases the height of the antenna profileand the complexity of the antenna An Archimedean spiralantenna that is fed in an unbalanced manner was proposedin 2009 by Nakano et al who in 2010 also proposed asingle-arm Archimedean spiral antenna whose bandwidth issufficiently wide [9 10] The single-arm Archimedean spiralantenna in [9] was built on a printed circuit board tomake theantenna practical [11] However the single-armArchimedeanspiral antennas in [9 11] do not function in the UHF bandthus they cannot be directly applied to PDdetection of powerequipment If these types of antennas are to be used manyparameters should be optimized

A single-arm Archimedean spiral antenna designedaccording to UHF detection requirements is thus developedin this studyThe eccentric feed method employed in [9 11] ismodified because of the change in parameters The effects ofvarious parameters on the antenna are discussed and several

Hindawi Publishing CorporationJournal of SensorsVolume 2014 Article ID 839386 8 pageshttpdxdoiorg1011552014839386

2 Journal of Sensors

well-designed trials are implemented to prove the practicalvalue of the proposed antenna

2 Antenna Design

21 Working Principle The working principle of a double-arm Archimedean spiral antenna can be explained with cur-rent band theory If the length difference between two armsis half of the wavelength the radiation on the adjacent spiralarms is superimposed As a result radiation is centered on thespiral ring belt the circumference of which is approximately120582 [12] The working principle of a single-arm Archimedeanspiral antenna can also be explained with current bandtheory The difference is that the radiation is not from twoantenna arms but from a single one which eventually shor-tens the effective length of the antenna armThe antenna canalso achieve circular polarization with a wideband afterappropriate adjustments

22 Antenna Structure Thestructure of the antenna is shownin Figure 1The antenna is mainly composed of a single spiralarm an FR4 board a disc and a coaxial pin A gradually cutstructurewas applied to this antenna to reduce the intensity ofthe terminal reflected current [13] A cone feed was utilized toimprove the frequency characteristics The antenna rotationis right-handed More details are provided in Figure 2 TheFR4 boardwith relative dielectric constant 120576 = 44 and dielec-tric loss tan 120575 = 0002 was selected as the substrate of theantenna The outer radius of the spiral (119877out) is 956mm andthe inner radius (119877in) is 159mm The number of spiral laps(119899) is 10 the antennarsquos arm width (119908) is 35mm and thespiral growth rate (119886sp) is 1267mmradThedistance betweenthe disc and spiral antenna (119867) is 5mm and the disc radius(119877disc) is 30mm

3 Simulation and Optimization

31 Simulation Model The popular electromagnetic simu-lation software ANSYS HFSS was utilized to design theantennaThe solver is based on finite elementmethod (FEM)To simplify the simulation process the thin metal sheet wasreplaced with a 2D plane and the boundary conditionwas setto perfect E The structure of the antenna can be understoodmore clearly if Figures 1 and 2 are considered togetherThe FR4 board whose influence on antenna performance isillustrated in the succeeding chapters was omitted in the earlysimulation processThe excitation port was set to the lumpedone

32 Analysis of the Simulation Results The features of theantenna were analyzed through fast sweep method thefrequency band of which is 05 GHzndash3GHz As an importantindicator of antenna performance the impedance character-istic is mainly related to the impedance matching case ofthe antenna VSWR and 119878

11are always utilized to value the

impedance matching case in engineering [14] If an antenna

Single spiralarm

FR4 board

Dielectric

Disc

H

x

zRinRout

Rdisc

Figure 1 Schematic of the antenna structure

Coneangle

DiscFeedport

Coaxialpin

W

L

X

Y

Z

Figure 2 Feeder structure of the simulation model

is equipped with only one port 11987811and reflection coefficient

Γ are equal in value The specific formulas are as follows

Γ = 11987811=119885119894minus 1198850

119885119894+ 1198850

VSWR = 1 + |Γ|1 minus |Γ|=1 +1003816100381610038161003816119878111003816100381610038161003816

1 minus1003816100381610038161003816119878111003816100381610038161003816

(1)

where 119885119894is the value of input impedance and 119885

0is the

characteristic impedance of the feed line the value of whichis mainly 50Ω If impedance matching is 119885

119894= 1198850 reflection

coefficient Γ becomes zero Thus the value of Γ or 11987811

isexpected to be small

Return loss which is one of the output parameters ofANSYS HFSS is also an important indicator of antennaperformance The calculation formula is

Return Loss = 10lg|Γ|2 = 20lg |Γ| = 20lg 1003816100381610038161003816119878111003816100381610038161003816

(2)

Journal of Sensors 3

052 075 100 125 150 175 200 225 250 274

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

Frequency (GHz)

Retu

rn lo

ss (d

B)

Figure 3 Frequency sweep analysis of return loss

Figure 3 shows the relationship between antenna returnloss and frequencyThe return loss which is less than minus10 dBcorresponds to the frequency band 115 GHzndash24GHz Theabsolute bandwidth becomes 125GHzHowever the antennaperformance at low or high frequency is less than expectedbecause of the changes in the effective radiation area of theantenna When the antenna operates at a low frequencythe radiation area is located at the edge where the effectiveradiation part is not long enough If the antenna operates at ahigh frequency the radiation area becomes the feed terminalwhich is near the disc and coaxial pinThese factors influenceantenna performance

Directivity which is another important performanceindex of the antenna is shown in Figure 4 The figure alsoprovides the 3D radiation pattern of the antenna operatingat the frequency of 12 GHz The antenna can radiate right-handed and left-handed polarized waves to both sides of theantenna plane similar to the traditional Archimedean spiralantenna The maximum radiation directivity is at the 119911-axis(120579 = 0180∘) Subsequent simulation shows that the radiationpattern at the 119909-119910 plane is no longer omnidirectional becausethe simulation frequency increases The radiation pattern isapproximately heart-shaped when the simulation frequencyis 17 GHz The radiation pattern becomes elliptical when thesimulation frequency is 20GHz

The phenomenon referred to above is shown in Figure 5The lobe splitting phenomenon will appear at the radiationpattern of the 119910-119911 plane if the simulation frequency continuesto increase These results suggest that the asymmetric struc-ture of the single-arm Archimedean spiral antenna resultsin the asymmetric radiation pattern of the antenna Whenthe effective radiation area is located within the range ofthe bottom disc the radiation pattern is completely affected[9] The radius of the disc is 30mm Thus if the antennaoperates at a frequency of more than 16GHz the effectiveradiation area will be located within the range of the discTheradiation pattern changes when the antenna operates at 17and 20GHz

The double-arm Archimedean spiral antenna is a typicalcircular-polarization antenna and the single-arm one canalso be utilized as a circular-polarization antenna Axial ratiois an important parameter to evaluate the performance ofcircular polarization The circularly polarized bandwidth is

49269e + 000

42175e + 000

35080e + 000

27966e + 000

20892e + 000

13798e + 000

67037e minus 001

minus39044e minus 002


minus14579e + 000

minus21673e + 000

minus42956e + 000

minus50050e + 000

minus57144e + 000

minus28767e + 000

minus35851e + 000

Gai

n to

tal (

dB)

Figure 4 3D radiation pattern of the antenna

minus520

minus240

90

60

30

0

minus30

minus60

minus90

minus120

minus150

minus180

150

120

f = 12Gf = 17Gf = 20G

020

040

Figure 5 2D right-handed polarized radiation pattern at the 119909-119910plane (120579 = 30∘)

usually defined as the frequency range that corresponds tothe axial ratio whose value is less than 3 dB The frequencyresponse of the antenna axis ratio is shown in Figure 6 Thecircularly polarized bandwidth is 062GHzndash203GHz andbasically meets the design requirement

33 Impact of the Antenna Parameters The FR4 board wasreplaced by air to simplify the simulation model Howeverantennas are typically fabricated on a printed circuit boardThus analyzing the effect of dielectric materials on antennaperformance is necessary When the dielectric is changed


Frequency (GHz)050 100 150 200 250 300

000

500

1000

1500

300

AR

(dB)

Figure 6 Frequency response of the antenna axis ratio

051 060 070 080 090 099

minus2279

minus1250

000

1250

2500

3617

ResidenceReactance

Frequency (GHz)

Zi

(Ω)

Figure 7 Frequency response of the antennarsquos input impedance

from air to FR4 which is utilized to manufacture theprinted circuit board the frequency response of the antennarsquosinput impedance changes immediately as shown in Figure 7Figure 7 also shows that the frequency band moves towardthe low-frequency band and the impedance decreases to30Ω Numerous simulations have indicated that if the size ofthe antenna remains constant impedance 119885

119894cannot be close

to 50Ω even if other parameters (except the dielectric mate-rial of the antenna) change significantly Thus in this studythe dielectricmaterial used between the antenna arm and discis not a single type Air and FR4 comprise the material Thethickness of the FR4 board is only 1mm and the thickness ofthe air layer is 4mm Several insulation brackets were utilizedto guarantee themechanical connection between the antennaarm and disc The simulation results show that the influenceof the dielectric can be ignored if the thickness of the FR4board is only 1mmThe previous simulation conclusions canbe employed in the current antenna If the antenna works inanother environment such as in the oil or in the SF

6gas

it is hard to calibrate the impedance changes because thedielectric between the antenna arm and disc changes So theantenna designed in this paper is suggested to use in the airat normal temperature

050 100 150 200 250 300

minus4500

minus3500

minus2500

minus1500

minus500

Frequency (GHz)

Angle = 42∘

Angle = 66∘Angle = 90∘

Angle = 102∘

S 11

(dB)

Figure 8 11987811corresponding to different cone angles

The inner radius of the spiral antenna is much largerthan the one mentioned in [11] because the working bandof the antenna is included in the UHF band If an eccentricfeedingmethod is employed the structure of the antenna willbecome unstable Thus a conical transition feeding methodwas employed to guarantee structural stability The value of11987811

that corresponds to different cone angles is shown inFigure 8The return loss characteristic of the antenna is idealwhen the cone angle is 90∘ If the cone angle is small thefeeding transition becomes insufficient Moreover when thecone angle becomes too large the current in the feedingmetal sheet which is out of the 90∘ range affects the originalcurrent Thus the cone angle should be 90∘

The width of the antenna arm affects the coupling caseof the adjacent arms Thus analyzing the influence causedby the antenna arm width is necessary If the arm width(119882) changes the separation distance between the adjacentantenna arms will also change Thus the duty ratio whichis defined as 119882119871 (the distance between adjacent arms)was applied to simplify the problem Figure 9 shows therelationship between VSWR and duty ratio at a frequencyof 19 GHz The optimal duty ratio ranges from 035 to 05Thus the duty ratio was set to 044 The effects of otherantenna parameters such as antenna section height and discradius have been fully described by Nakano et al [9] and aretherefore not discussed here

4 Partial Discharge MeasurementResults and Analysis

Three typical power equipment defect models were design-ed to verify the detection capability of the single-arm Archi-medean spiral antenna in the laboratory A typical microstripantenna and a pulse current detection method were alsoutilized to determine whether the single-arm Archimedeanspiral antenna has a practical value in UHF detection

41 Artificial Insulation Defect Model Artificial insulationdefect models were designed based on the models in [15]


Duty ratio

VSW

R

025 035 045 055 065

100

120

140

158

Figure 9 VSWR corresponding to different duty ratios

Epoxyboard

Cylindricalelectrode

Discelectrode

(a) (b) (c)

Figure 10 Three typical power equipment defect models (a)Corona (b) Air-gap discharge (c) Surface discharge

The preparationmethods were adopted from [16]Themodelstructure is shown in Figure 10 The diameter of the cylin-drical electrode is 25mm and the diameter of the disc elec-trode is 80mm which is equal to the diameter of the epoxyboard whose thickness is 05 mm The air-gap defect modelconsists of three epoxy boards themiddle one has a hole witha diameter of 38mmThe curvature radius of the needle elec-trode utilized in the corona defect model is 200120583m and thedistance between the needle electrode and the epoxy boardis approximately 3mm All the artificial insulation defectmodels were placed in glass containers filledwith transformeroil to simulate the discharge in the transformer oil

The wiring diagram is shown in Figure 11 Detectionimpedance was utilized to obtain the pulse current signalcaused by PD The UHF signal captured by the antennasis transported to the oscilloscope through the transmissioncable The distance of the cable is equal to the one used totransport the signal fromdetection impedanceThe detectionimpedance was concatenated into the grounding line of thedefect model and the antennas were set 40 cm far awayfrom the defect model All the test was carried out in theshielding roomwhose size is 6m times 4m times 33mThemaximalsensitivity of the single-arm Archimedean spiral antennaranges from 35 dBi to 73 dBi when the antenna works atdifferent frequencies

Thebackgroundnoise should bemeasured before the testThe signal from the single-arm Archimedean spiral antennathe signal from the typical microstrip antenna and detection

380V

1

2

3

5

6 Z

7

8

4

Figure 11 Experiment wiring diagram (1) Regulator (2) Testtransformer (3) Protection resistor (4) Coupling capacitor (5)Defect model (6) Detection impedance (7) Oscilloscope (8) UHFantennas

impedance were measured simultaneously The inceptiondischarging voltage of each defect was recorded as U

0 and

the final test voltage under which the PD signal was obtainedshould be 12U

0 The distance between the UHF antennas

(including the spiral and microstrip antennas) and the defectmodels is 40 cm and the length of the transmission cables isthe same

42 Test Results and Analysis The background noise mea-sured by the single-arm Archimedean spiral antenna is135mV No significant pulse interference was observedthroughout the entire test time In addition the backgroundnoise level remained stable The corona discharge signalobtained by the spiral antenna and detection impedanceare shown in Figure 12 The measurement result shows thatthe signal-to-noise ratio (SNR) of the designed antenna issatisfactory and that corona discharge always occurs at thepeak value of the test voltage Moreover the discharge atthe negative peak value is more likely to induce the UHFsignal the phenomenon can be explained through needle-plate electrode discharge theory [17] Although PD occursat the positive peak value the measurement sensitivity ofthe spiral antenna is not sufficiently good compared with itsdetection impedance The long distance between the needleand disc electrode leads to the long increase time of thepositive polarity current pulse and the UHF signal which isinduced by the current pulse that attenuates at the same time[18]

Figure 13 shows the air-gap discharge signal obtained bythe spiral antenna Compared with the corona discharge inoil the air-gap discharge appears to be more active It alwaysoccurs in the 0∘ndash90∘ and 180∘ndash270∘ phases of the test voltageWithin these ranges the absolute value of the test voltageincreases Given that gas insulation is a type of recoverableinsulation PD also disappears when the value of the voltagedecreases Thus air-gap discharge always occurs in the 14and 34 periods of the power frequency voltage [19]

Figure 14 shows that the PD characteristic of the sur-face discharge model is not obvious and the amplitude of


0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance

Figure 12 Corona discharge signal

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Figure 13 Air-gap discharge signal

the signal from the detection impedance is small The UHFsignal acquired by the spiral antenna is almost covered bybackground noise The development of surface discharge isrelatively slow and the experiment time is too short to obtaina good PD result [20] Thus the detection result of theantenna is not sufficiently good Increasing the test time andperforming signal denoising are necessary to obtain bettersurface discharge data

The above analysis shows that the spiral antenna designedin this study can effectively detect the PD signals originatingfrom the typical transformer insulation defect models Thephase characteristic of the signal is obvious The SNR ofthe antenna meets the requirement of general measurement

0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance

Figure 14 Surface discharge signal

and the antenna can be utilized for UHF detection Tosimulate the PD phenomenon that occurs in the power trans-former accurately the test time and artificial model should bedesigned reasonably

43 Comparative Tests with the Microstrip Antenna Theexternal dimension of the microstrip antenna with centerfrequency of 900MHz is 158 cm times 125 cm Thus the area ofthe microstrip antenna is close to 200 cm2 The area of theantenna designed in this study is approximately 280 cm2The microstrip and spiral antennas receive the UHF signalgenerated by the same PD source simultaneouslyThe denois-ing function ldquowdenrdquo in Matlab was applied to pretreat thedata Figure 15 shows the output signal of the two antennasduring one voltage cycle the defect mode is air-gap defectThe detection sensitivity of the spiral antenna is significantlyhigher than that of the microstrip antenna Although thearea of the spiral antenna is slightly larger than that of themicrostrip one the sensitivity of the spiral antenna is anorder of magnitude higher than that of the typical microstripantenna Using the spiral antenna to detect the PD signal ofair-dap defect whose energy concentration is at a frequencylower than 1GHz appears to be insufficient [16] Howeveras long as the spiral antenna makes full use of the energyseparated at a high frequency its detection effect is better thanthat of a narrow band antenna

5 Conclusion

A single-arm Archimedean spiral antenna operating at afrequency band of 115 GHzndash24GHz was designed Its per-formancewas studied in the laboratoryThemain conclusionsare as follows


0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance

Figure 15 PD signal of the air-gap model during one cycle

(1) The single-arm Archimedean spiral antenna can bedirectly fed by a 50Ω coaxial cable and can operateat the ultra-high frequency bandThe structure of thesingle-arm antenna differs from that of the single-armone in [9]

(2) The bandwidth of the single-arm Archimedean spiralantenna is wide and its section height is lower thanthat of the traditional double-arm antenna Howevercompared with the double-arm antenna the direc-tional characteristics of the single-arm antenna arenot good enough and its surface area is larger

(3) The single-arm Archimedean spiral antenna candetect the PD signal originating from the transformerinsulation defect The sensitivity of the antennais significantly higher than that of a narrowbandantenna and it is the first time to use the single-arm Archimedean spiral antenna in the field of PDdetection

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The study is supported by the National Science Foundation ofChina (51321063)

References

[1] G Wang Y Zheng Y Hao et al ldquoStudy on the ultra-high-frequency sensor for PD detection in power transformerrdquoProceedings of the CSEE vol 22 no 4 pp 155ndash161 2002

[2] H Li ldquoAnalysis and design of a new-type planar Archimedeanspiral antennardquo Radar and Confrontation no 3 pp 43ndash45 532006

[3] Z He F Xu and J Cui ldquoDesign of miniaturized planar spiralsatellite antennardquo Spacecraft Engineering vol 21 no 1 pp 68ndash71 2012

[4] Z Song H Li H Yang et al ldquoStudy on aminiaturizedmeanderArchimedean spiral antennardquo Journal ofMicrowaves vol 25 no2 pp 53ndash57 2009

[5] Y Zhu S Zhong S Xu et al ldquoDesign of miniaturized planarspiral antenna and its wideband balunrdquo Journal of ShangHaiUniversity Natural Science vol 14 no 6 pp 581ndash584 2008

[6] Y Wang G Wang and J Liang ldquoDesign of a Archimedeanspiral antenna with low-profilerdquo Journal of Microwaves vol 28no 4 pp 5ndash9 2012

[7] N Rahman and M N Afsar ldquoA novel modified archimedeanpolygonal spiral antennardquo IEEE Transactions on Antennas andPropagation vol 61 no 1 pp 54ndash61 2013

[8] L Li ldquoDesign and analysis of complementary Archimedeanspiral antennardquo Telemetry and Remote Control vol 24 no 04pp 31ndash36 2003

[9] H Nakano R Satake and J Yamauchi ldquoExtremely low-profilesingle-arm wideband spiral antenna radiating a circularlypolarized waverdquo IEEE Transactions on Antennas and Propaga-tion vol 58 no 5 pp 1511ndash1520 2010

[10] H Nakano T Igarashi H Oyanagi Y Iitsuka and J YamauchildquoUnbalanced-mode spiral antenna backed by an extremely shal-low cavityrdquo IEEE Transactions on Antennas and Propagationvol 57 no 6 pp 1625ndash1633 2009

[11] Z Liu Z Qian and Z Han ldquoDesign of a conformal widebandcircularly polarized spiral antennardquo Telecommunication Engi-neering vol 51 no 11 pp 94ndash98 2011

[12] J Kaiser ldquoThe Archimedean two-wire spiral antennardquo IRETransactions on Antennas and Propagation vol 8 no 3 pp 312ndash323 1960

[13] B Shanmugam and S K Sharma ldquoInvestigations on a novelmodified archimedean spiral antennardquo in Proceedings of theIEEE International Symposium on Antennas and Propagation(APSURSI rsquo11) pp 1225ndash1228 Spokane Wash USA July 2011

[14] L Zhang Study of compactmicro-strip antennas with wide-bandand multi-band [MS thesis] Dept Radio Physics East ChinaNormal Univ Shanghai China 2005

[15] J Li J-X Ning Z-R Jin Y-Y Wang and M Li ldquoResearchon UHF Hilbert fractal antenna for online transformer PDmonitoringrdquo Electric Power Automation Equipment vol 27 no6 pp 31ndash35 2007

[16] C Cheng Study on fourth-order fractal antenna and signalprocessing and recognition for UHF monitoring of PDs in powertransformers [MS thesis] Department of Electronic Engineer-ing Chongqing University Chongqing China 2009

[17] J Kuffel W S Zaengl and E Kuffel High Voltage EngineeringFundamentals Butterworth-Heinemann Oxford UK 2nd edi-tion 2000

[18] X H Zhao J G Yang X L Lu P Yuan S Wang and Y MLi ldquoComparative research on current pulse method and UHFmeasurements of partial discharge in mineral oilrdquoHigh VoltageEngineering vol 34 no 7 pp 1401ndash1404 2008


[19] W-G Chen C Wei C-X Sun and J Tang ldquoAir-gap dischargecharacteristics in transformer oil-paper insulation and gasgeneration lawrdquo High Voltage Engineering vol 36 no 4 pp849ndash855 2010

[20] W G Chen J F Yang Y Ling and X Chen ldquoSurface dischargecharacteristics and gas generation law in oil-paper insulation oftransformerrdquo Journal of Chongqing University vol 34 no 1 pp94ndash99 2011

International Journal of

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Control Scienceand Engineering

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Hindawi Publishing Corporation httpwwwhindawicom

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Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



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Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



well-designed trials are implemented to prove the practicalvalue of the proposed antenna

2 Antenna Design

21 Working Principle The working principle of a double-arm Archimedean spiral antenna can be explained with cur-rent band theory If the length difference between two armsis half of the wavelength the radiation on the adjacent spiralarms is superimposed As a result radiation is centered on thespiral ring belt the circumference of which is approximately120582 [12] The working principle of a single-arm Archimedeanspiral antenna can also be explained with current bandtheory The difference is that the radiation is not from twoantenna arms but from a single one which eventually shor-tens the effective length of the antenna armThe antenna canalso achieve circular polarization with a wideband afterappropriate adjustments

22 Antenna Structure Thestructure of the antenna is shownin Figure 1The antenna is mainly composed of a single spiralarm an FR4 board a disc and a coaxial pin A gradually cutstructurewas applied to this antenna to reduce the intensity ofthe terminal reflected current [13] A cone feed was utilized toimprove the frequency characteristics The antenna rotationis right-handed More details are provided in Figure 2 TheFR4 boardwith relative dielectric constant 120576 = 44 and dielec-tric loss tan 120575 = 0002 was selected as the substrate of theantenna The outer radius of the spiral (119877out) is 956mm andthe inner radius (119877in) is 159mm The number of spiral laps(119899) is 10 the antennarsquos arm width (119908) is 35mm and thespiral growth rate (119886sp) is 1267mmradThedistance betweenthe disc and spiral antenna (119867) is 5mm and the disc radius(119877disc) is 30mm

3 Simulation and Optimization

31 Simulation Model The popular electromagnetic simu-lation software ANSYS HFSS was utilized to design theantennaThe solver is based on finite elementmethod (FEM)To simplify the simulation process the thin metal sheet wasreplaced with a 2D plane and the boundary conditionwas setto perfect E The structure of the antenna can be understoodmore clearly if Figures 1 and 2 are considered togetherThe FR4 board whose influence on antenna performance isillustrated in the succeeding chapters was omitted in the earlysimulation processThe excitation port was set to the lumpedone

32 Analysis of the Simulation Results The features of theantenna were analyzed through fast sweep method thefrequency band of which is 05 GHzndash3GHz As an importantindicator of antenna performance the impedance character-istic is mainly related to the impedance matching case ofthe antenna VSWR and 119878

11are always utilized to value the

impedance matching case in engineering [14] If an antenna

Single spiralarm

FR4 board

Dielectric

Disc

H

x

zRinRout

Rdisc

Figure 1 Schematic of the antenna structure

Coneangle

DiscFeedport

Coaxialpin

W

L

X

Y

Z

Figure 2 Feeder structure of the simulation model

is equipped with only one port 11987811and reflection coefficient

Γ are equal in value The specific formulas are as follows

Γ = 11987811=119885119894minus 1198850

119885119894+ 1198850

VSWR = 1 + |Γ|1 minus |Γ|=1 +1003816100381610038161003816119878111003816100381610038161003816

1 minus1003816100381610038161003816119878111003816100381610038161003816

(1)

where 119885119894is the value of input impedance and 119885

0is the

characteristic impedance of the feed line the value of whichis mainly 50Ω If impedance matching is 119885

119894= 1198850 reflection

coefficient Γ becomes zero Thus the value of Γ or 11987811

isexpected to be small

Return loss which is one of the output parameters ofANSYS HFSS is also an important indicator of antennaperformance The calculation formula is

Return Loss = 10lg|Γ|2 = 20lg |Γ| = 20lg 1003816100381610038161003816119878111003816100381610038161003816

(2)


052 075 100 125 150 175 200 225 250 274

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

Frequency (GHz)

Retu

rn lo

ss (d

B)






49269e + 000

42175e + 000

35080e + 000

27966e + 000

20892e + 000

13798e + 000

67037e minus 001



minus14579e + 000

minus21673e + 000

minus42956e + 000

minus50050e + 000

minus57144e + 000

minus28767e + 000

minus35851e + 000

Gai

n to

tal (

dB)


minus520

minus240

90

60

30

0

minus30

minus60

minus90

minus120

minus150

minus180

150

120

f = 12Gf = 17Gf = 20G

020

040





Frequency (GHz)050 100 150 200 250 300

000

500

1000

1500

300

AR

(dB)


051 060 070 080 090 099

minus2279

minus1250

000

1250

2500

3617

ResidenceReactance

Frequency (GHz)

Zi

(Ω)





6gas


050 100 150 200 250 300

minus4500

minus3500

minus2500

minus1500

minus500

Frequency (GHz)

Angle = 42∘


Angle = 102∘

S 11

(dB)









Duty ratio

VSW

R

025 035 045 055 065

100

120

140

158


Epoxyboard


Discelectrode

(a) (b) (c)





380V

1

2

3

5

6 Z

7

8

4



0 and








0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance


0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna




0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance




5 Conclusion



0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










052 075 100 125 150 175 200 225 250 274

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

Frequency (GHz)

Retu

rn lo

ss (d

B)






49269e + 000

42175e + 000

35080e + 000

27966e + 000

20892e + 000

13798e + 000

67037e minus 001



minus14579e + 000

minus21673e + 000

minus42956e + 000

minus50050e + 000

minus57144e + 000

minus28767e + 000

minus35851e + 000

Gai

n to

tal (

dB)


minus520

minus240

90

60

30

0

minus30

minus60

minus90

minus120

minus150

minus180

150

120

f = 12Gf = 17Gf = 20G

020

040





Frequency (GHz)050 100 150 200 250 300

000

500

1000

1500

300

AR

(dB)


051 060 070 080 090 099

minus2279

minus1250

000

1250

2500

3617

ResidenceReactance

Frequency (GHz)

Zi

(Ω)





6gas


050 100 150 200 250 300

minus4500

minus3500

minus2500

minus1500

minus500

Frequency (GHz)

Angle = 42∘


Angle = 102∘

S 11

(dB)









Duty ratio

VSW

R

025 035 045 055 065

100

120

140

158


Epoxyboard


Discelectrode

(a) (b) (c)





380V

1

2

3

5

6 Z

7

8

4



0 and








0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance


0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna




0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance




5 Conclusion



0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Frequency (GHz)050 100 150 200 250 300

000

500

1000

1500

300

AR

(dB)


051 060 070 080 090 099

minus2279

minus1250

000

1250

2500

3617

ResidenceReactance

Frequency (GHz)

Zi

(Ω)





6gas


050 100 150 200 250 300

minus4500

minus3500

minus2500

minus1500

minus500

Frequency (GHz)

Angle = 42∘


Angle = 102∘

S 11

(dB)









Duty ratio

VSW

R

025 035 045 055 065

100

120

140

158


Epoxyboard


Discelectrode

(a) (b) (c)





380V

1

2

3

5

6 Z

7

8

4



0 and








0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance


0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna




0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance




5 Conclusion



0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Duty ratio

VSW

R

025 035 045 055 065

100

120

140

158


Epoxyboard


Discelectrode

(a) (b) (c)





380V

1

2

3

5

6 Z

7

8

4



0 and








0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance


0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna




0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance




5 Conclusion



0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0 20 40 60 80 100 120

0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus5

0

5

minus01

0

01

minus5

0

5

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance


0 20 40 60 80 100 120

0 20 40 60 80 100 120

minus10

0

10

minus02

0

02

t (ms)

t (ms)

Um

(V)

Um

(V)

Power frequency

Spiral antenna




0 10 20 30 40 50 60

0 10 20 30 40 50 60

0 10 20 30 40 50 60

minus20

0

20

minus001

0

001

minus01

0

01

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Power frequency

Spiral antenna

Detection impedance




5 Conclusion



0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0 5 10 15 20 25

0 5 10 15 20 25

0 5 10 15 20 25minus2

0

2

minus002

0

002

minus5

0

5

times10minus3

Microstrip antenna

t (ms)

t (ms)

t (ms)

Um

(V)

Um

(V)

Um

(V)

Spiral antenna

Detection impedance







Acknowledgment


References
























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Research Article Design of a UHF Antenna for Partial Discharge … · 2020. 1. 13. · arm...

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Transcript of Research Article Design of a UHF Antenna for Partial Discharge … · 2020. 1. 13. · arm...