Microsoft Word - 1-2696-S_ETASR_V9_N4_pp4315-4321


Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4315 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

Study of The Phenomena of Surface Discharges and 
Flashover in Nanocomposite Epoxy Resin under the 

Influence of Homogeneous Electric Fields 
 

D. Verginadis 
Democritus University of Thrace, 

Department of Electrical and Computer 
Engineering, Xanthi, Greece 

dimoverg2@ee.duth.gr 

M. G. Danikas 
Democritus University of Thrace, 

Department of Electrical and Computer 
Engineering, Xanthi, Greece 

mdanikas@ee.duth.gr 

R. Sarathi 
Indian Institute of Technology Madras  
Department of Electrical Engineering  

Chennai, India 
sarathi@ee.iitm.ac.in 

 

 

Abstract—A new class of insulating materials is the class of 

polymer nanocomposites. In the past twenty-five years, a lot of 

attention was paid to the various electrical, thermal and 
mechanical properties of polymer nanocomposite materials. In 

the present work, epoxy resin samples without and with 

nanoparticles (0 wt%, 1 wt%, 3 wt%, 5 wt%, and 10 wt%) are 

investigated regarding the surface discharges and the flashover 

voltages. Four different water droplet arrangements were used, 

with eight different water conductivities in order to see the effect 
of the nanoparticle content on the surface discharges and the 
flashover voltages. 

Keywords-polymer nanocomposites; nanoparticles; surface 

discharges; flashover voltage 

I. INTRODUCTION  

A nanocomposite is defined as a material having 
constituents, one of which has dimensions in the nanorange. 
Intensive research in the field of nanocomposites started 
especially after the publication of [1]. Numerous other 
publications followed explaining the workings of such 
materials [2, 3]. Models have been proposed and commented 
upon regarding the behavior of the polymer nanocomposites [4, 
5]. It was shown that polymer nanocomposites present 
improved electrical, thermal and mechanical properties 
compared with the respective conventional polymers. Polymer 
nanocomposites have been applied in various industries, such 
as the automobile industry, the building industry and the food 
industry. Although much research has been carried out on 
various aspects of polymer nanocomposites, relatively little is 
known w.r.t. their surface discharge and flashover behavior [6]. 
As reported before, surface phenomena in polymer 
nanocomposites are important because they determine to a 
significant extent their behavior in indoor as well as in outdoor 
high voltage applications [7]. Surface discharges and 
consequently the flashover phenomenon are due, among other 
factors, to the presence of water droplets on the polymer 
nanocomposite surface. It is the aim of this paper to investigate 
the influence of various water droplet arrangements, with 
various water conductivities, under uniform electrical fields on 
epoxy resin nanocomposite surfaces. A sample with no 

nanoparticles at all was used as reference. The epoxy resin 
nanocomposites contained nanoparticles of percentages 1wt%, 
3wt%, 5wt% and 10wt%. The present work continues previous 
work conducted with the same samples [7]. 

II. WATER DROPLET BEHAVIOR 

Water droplets on an insulating surface under the influence 
of an electrical field tend to deform. Surface discharges follow 
such deformation. Dry zones may ensue, then local arcs and 
finally a flashover. Such a sequence of events is more or less 
common in both indoor and outdoor high voltage applications, 
although there are some differences [8, 9]. When a droplet 
becomes unstable because of a deformation, tiny droplets may 
be rocketed from it. The initial droplet oscillates violently and 
the tiny droplets are highly charged. The main droplet becomes 
smaller in size as well as in electric charge. Under an electric 
field this is an ongoing process which may lead to intense 
surface discharging, formation of dry zones and then local 
arcing. Relevant research performed in the past revealed that, 
in the case of polymer nanocomposites, the contact angle of the 
water droplet increases with the increase of the nanoparticle 
content and that the positioning of the droplet w.r.t. the 
electrodes is also important [10, 11]. 

III. EXPERIMENTAL ARRANGEMENT AND INSULATING 
MATERIALS 

The experimental arrangement used is described in detail in 
earlier publications [7, 12] and only a brief mention will be 
given here. The voltage was supplied from a 20kV transformer. 
The electrodes were made of copper and had a half cylindrical 
shape with rounded edges. Needless to say that care was taken 
so that their surfaces were very smooth. The water droplets are 
shown in Figures 1-4, and they were positioned on the sample 
in four different arrangements. It must be emphasized that two 
of the droplet arrangements in the present paper (those of 
Figures 3 and 4) are different from the ones described in [7]. 
Eight different water conductivities were used, namely 
1.4µS/cm, 100µS/cm, 200µS/cm, 500µS/cm, 1000µS/cm, 
2000µS/cm, 5000µS/cm and 10000µS/cm. In Figure 1, one 
droplet of volume 0.05ml (or 0.1ml) was put at a distance of 

Corresponding author: M. G. Danikas



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4316 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

1.25cm from the electrodes. In Figure 2, two droplets (each of 
0.05ml or 0.1ml) were positioned one next to the other at a 
distance of 0.8cm between them and 0.8cm from the 
electrodes. In Figure 3, two droplets were positioned one on top 
of the other of 0.05ml (or of 0.1ml) at a distance of 1.25cm 
from the electrodes and at a distance of 1 cm from each other. 
In Figure 4, three droplets were positioned, each of 0.05ml (or 
0.1ml) at a distance of 1.25cm from the electrodes. 

 

 
Fig. 1.  One-droplet arrangement 

 
Fig. 2.  Two-droplets arrangement 

 
Fig. 3.  Two-droplets arrangement 

The polymer nanocomposite used was epoxy resin plates 
having nanoparticles with 1wt%, 3wt%, 5wt% and 10wt%. A 
reference sample with no nanoparticles at all was also used.The 
epoxy nanocomposite was synthesized by mechanical shear 
mixing of organo-clay in the resin bath at room temperature. 
The high speed shear mixer consists of an impeller which 
rotates at a high speed of 2000rpm.The clay mineral used was 
organophilic montmorillonite (MMT) procured from Southern 
Clay products Inc. (Gonzales, Texas) with the trade name of 
Garamite1958 (colour: off white, bulk density: 1.5-1.7g/cc, 
weight loss at 10000C: 37%, d spacing at d001: 17.2Å). 

 
Fig. 4.  Three-droplets arrangement 

After uniform mixing of MMT clay in epoxy resin (which 
was DGEBA, CY205, Ciba Geigy Inc.), 10 wt% of 
triethylenetetramine (TETA) hardener was added and then 
casted in a mould of required dimension and then degassed. 
The MMT clay belongs to a family of 2:1 layered silicates. 
Epoxy nanocomposites of 3mm thickness with different 
percentages (1–10%) of clay were prepared [7]. The surface 
roughness of the samples was measured with a Perthen device 
(Perthometer M4P) and it gave the following results 
(minimum-maximum roughness): for the 0wt% (reference) 
sample from 0.59µm to 0.69µm, for the 1wt% sample from 
0.60µm to 0.79µm, for 3wt% sample from 0.49µm to 0.59µm, 
for the 5wt% sample from 0.60µm to 0.68µm and for the 
10wt% sample from 0.22µm to 0.22µm. 

IV. EXPERIMENTAL METHOD 

The parameters investigated in this work were the water 
conductivity, the number of droplets, the droplet volume and 
the positioning of the droplets w.r.t. the electrodes. The 
experimental method followed was the same as in previous 
papers [7] and it will briefly be given here: the droplet(s) were 
put on the polymer surface. Then the voltage was raised until 
flashover happened. After that, new droplet(s) of the same 
number, volume and positioning were put on the surface and 
the voltage was raised up to a voltage which was lower by 
1.2kV from the previous flashover. At this voltage the whole 
arrangement would stay for 5 minutes. If no flashover 
occurred, the voltage was raised by further 0.4kV and kept for 
another 5 minutes and this went on until flashover occurred. 
That was the flashover that was recorded. The reason the 
voltage was allowed to stay for 5 minutes at each value was 
because we wanted to see whether the droplet (or droplets) 
were deforming and whether surface discharging was starting. 
As in the previous publication [7], we thought that 5 minutes 
was enough time in order to see the oscillation and eventual 
deformation of the droplet(s), the development of surface 
discharges and the actual flashover. Needless to say that for 
every new experiment, the electrodes were meticulously 
cleaned. The distance between the electrodes in all experiments 
was set at 2.5cm. The droplets were put on the polymer surface 
with the aid of a syringe. Different syringes were used for the 
different water conductivities. Flashover occurred either 
through the air (Figure 5) or through the droplets (Figure 6). 

V. EXPERIMENTAL RESULTS 

Figure 7 shows the variation of flashover voltage with water 
conductivity for one droplet of 0.05 ml. Figure 8 shows the 



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4317 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

variation of flashover voltage with water conductivity for two 
droplets next to each other, each having a volume of 0.05ml. 

 

 
Fig. 5.  Flashover through the air 

 
Fig. 6.  Flashover through the water droplets 

Figure 9 shows the variation of flashover voltage with 
water conductivity for two droplets of 0.05 ml each and being 
one on top of the other. Figure 10 shows the variation of 
flashover voltage with water conductivity for the three droplets, 

each having a volume of 0.05ml. Figure 11 shows the variation 
of flashover voltage with water conductivity for one droplet of 
0.1ml. Figure 12 shows the variation of flashover voltage with 
water conductivity for two droplets next to each other, each 
having a volume of 0.1ml. Figure 13 shows the variation of 
flashover voltage with water conductivity for two droplets of 
0.1ml each and being one on top of the other. Figure 14 shows 
the variation of flashover voltage with water conductivity for 
the three droplets, each having a volume of 0.1ml. It must be 
noted that in all Figures the blue line indicates the sample with 
0wt% nanoparticles, the red line indicates the sample with 
1wt% nanoparticles, the yellowline indicates the sample with 
3wt% nanoparticles, the purple line indicates the sample with 
5wt% nanoparticles and the greenline indicates the sample with 
10wt% nanoparticles. 

VI. DISCUSSION 

In most experiments there was an oscillation of the 
droplet(s), which eventually were breaking up. For the droplets 
arrangement of the three droplets, it was noticed that there was 
too often a deformation and eventual break-up of the middle 
droplet. In the case of the two droplets, with one next to the 
other, it was often observed an oscillation and eventual coming 
together of the two droplets. In all results, irrespective of the 
number and/or the volume of droplets, water conductivity 
seems to lower the flashover voltage. As the conductivity 
increases, the flashover voltage decreases. The volume of the 
droplets plays also an important role, i.e. the flashover voltage 
seems to be lower for the 0.1ml droplet(s) than for the 0.05ml 
droplet(s). The positioning of the droplets w.r.t. the electrodes 
plays also a vital role, i.e. as the distance of the droplet(s) from 
the electrodes becomes smaller, the flashover voltage decreases 
(compare for example, the results between Figures 12-13). 

 
Fig. 7.  Comparison of flashover voltages for one droplet of 0.05ml 

 
Fig. 8.  Comparison of flashover voltages for two-droplets arrangement of 0.05ml each (one droplet next to the other)  



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4318 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

 
Fig. 9.  Comparison of flashover voltages for two-droplets arrangement of 0.05ml each (one droplet on top of the other)  

 

 
Fig. 10.  Comparison of three-droplets arrangement of 0.05ml each 

 

 
Fig. 11.  Comparison of one-droplet arrangement of 0.1ml  

 

 
Fig. 12.  Comparison of two-droplets arrangement of 0.1ml each (one droplet next to the other)  



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4319 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

 
Fig. 13.  Comparison of two-droplets arrangement of 0.1ml each (one droplet on top of the other) 

 
Fig. 14.  Comparison of three-droplets arrangement of 0.1ml each  

This reminds us of a similar effect with the partial 
discharges, where cavities next to electrodes give higher 
discharge magnitudes than cavities which are totally enclosed 
in the solid insulation [13-15]. Certainly, the proximity with the 
electrodes seems to initiate more easily electron emission in 
either case. The polymer nanocomposite surface is of great 
importance for the flashover data. It seems that nanocomposites 
with 1wt% and 3wt% nanoparticles have higher flashover 
voltages than the pure epoxy resin (with 0wt%), whereas the 
sample with 5wt% nanoparticles has comparable flashover 
voltages with the pure epoxy resin. The polymer 
nanocomposite with 10wt% nanoparticles gives the lowest 
results, even lower than the pure epoxy resin. The fact that 
polymer nanocomposites have higher flashover voltages than 
pure epoxy resin seems to agree with previous published 
research [16], where it was pointed out that the depth of erosion 
in pure polymers is larger than the erosion depth of polymer 
nanocomposites. This was attributed to the coming onto the 
surface of the nanoparticles and this contributes to the lowering 
of the surface discharges. However, as noted, a big increase of 
nanoparticle content does not necessarily imply the increase of 
flashover voltage. The 10wt% nanocomposite in our 
experiments did not perform well, even in comparison with the 
pure epoxy resin. The results of the present work agree with 
those published before, albeit with somehow different droplet 
arrangements [7, 17]. It may be that, as the percentage of 
nanoparticles increases beyond a certain value, agglomerations 
of nanoparticles may appear which may be sites of further 
discharging and of eventual erosion of the nanocomposite 

surface. This explanation, however, has to be further 
investigated. An ever increasing percentage of nanoparticles in 
a polymer may not be advisable in the light of other 
experimental evidence, as was noted elsewhere [18, 19]. 

The problem of the negative effect of exceeding 
nanoparticle content in a polymer has to be further investigated. 
A lot of research has been done regarding the effect of 
nanoparticle agglomerations on partial discharge activity [20, 
21]. It is established that nanoparticle agglomerations may 
hinder the electrical performance of a polymer nanocomposite 
and may lower its breakdown strength. However, when one 
comes to the surface discharge behavior of the polymer 
nanocomposites, relevant information is missing or it is rather 
scant. There are reports of improvement of flashover voltage 
with the addition of carbon black nanoparticles (1 wt%) in 
ethyl-vinyl acetate [22]. According to the authors of [22], the 
improvement is attributed to the introduction of deeper traps 
capturing the charges and thus increasing the flashover voltage. 
In yet another work [23], the authors claimed that low 
nanoparticle content (1wt%) increases the density of deep traps 
and helps in improving the flashover voltage. However, with 
higher nanoparticle content, distances between adjacent 
nanoparticles decrease. Overlapped interaction zones of 
nanoparticles are quasi-conductive and they raise the energy 
level of traps. Deep traps are replaced by shallow traps and the 
latter contribute to charge dissipation. This in turn increases the 
mobility of carriers and increases the conductivity of 
nanocomposites. Consequently, charge carriers tend to move 



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4320 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

through connected interaction zones more freely and thus 
triggering of a surface flashover becomes more probable. The 
above may be an explanation as to why higher nanoparticle 
content lowers the flashover voltage, but it is advisable to 
perform further research on the subject. An interesting topic of 
further contemplation may be about the role of nanoparticle 
agglomerations, since these, although they play a negative role 
in internal discharges, at least according to some researchers 
may play a positive role for surface flashover [16]. According 
to [16], nanoparticles may come onto the surface after the 
occasional erosion, and thus may act as minute barriers against 
the development of either a surface discharge or a flashover. 
There is, however, another point of view offered in [24]. 
According to [24], nanoparticles coming onto the surface of the 
nanocomposite, may agglomerate and cause local asymmetrical 
fields because of their higher dielectric constant. Further work 
is urgently needed in order to clarify the whole mechanism. 
Needless to say that all the above have to be investigated in the 
light of the morphology of polymer matrix, of processing 
conditions, of lamellar thickening process, and of crystallinity 
[25]. 

The present experimental results give an idea as to the 
parameters affecting the water droplet behavior on 
conventional and nanocomposite polymeric surfaces. A better 
picture may emerge if there will be more experiments w.r.t. the 
evolution of droplets with time. It is hoped that with this kind 
of experiments, details of the break-up of droplets will emerge 
with the aid of ultra-fast photographic apparatus. Even more 
interesting would be the clarification of the role of 
nanoparticles with surface ageing, since it was reported that 
nanoparticles affect decisively the surface roughness during the 
ageing process [26]. The results of the present work point out 
to the influence of water conductivity, number of droplets as 
well as of their positioning on the flashover voltage. Relatively 
little influence has the surface roughness of the polymer 
nanocomposite, as is evident in the results presented here. The 
latter remark is at variance with previously published work [27] 
(it must, however, be noticed that in [27], different insulating 
materials from the ones used in this work were used). The 
10wt% nanocomposite has the lowest roughness but it also has 
the worst performance from all samples. The conclusions of the 
present work, regarding the above mentioned factors, agree 
qualitatively with previously published research [28, 29]. 

VII. CONCLUSIONS 

Factors that affect the flashover voltage in polymer 
nanocomposites are the water droplet conductivity, the number 
of droplets on the polymer surface and the positioning of the 
droplets w.r.t. the electrodes. The highest flashover voltages 
were noted with samples having nanoparticles in the range of 1 
wt% up to 3 wt%. Such percentages agree qualitatively with 
experimental results of other researchers. Higher nanoparticle 
content may cause a decrease of flashover voltage. Whether 
this is due to nanoparticle agglomerations or whether it is due 
to some inner workings of interaction zones between the 
nanoparticles remains to be seen. 

 

 

ACKNOWLEDGMENT 

The present work was carried out with samples of epoxy 
resin nanocomposites, which were built at the Department of 
Electrical Engineering, Indian Institute of Technology Madras, 
India. 

REFERENCES 

[1] T. J. Lewis, “Nanometric dielectrics”, IEEE Transactions on Dielectrics 
and Electrical Insulation, Vol. 1, pp. 812-825, 1994 

[2] J. K. Nelson, Dielectric polymer nanocompsites, Springer, 2010 

[3] T. Tanaka, “Dielectric nanocomposites with insulating properties”, IEEE 
Transactions on Dielectrics and Electrical Insulation, Vol. 12, No. 5, pp. 
914-928, 2005 

[4] M. G. Danikas, “On two nanocomposite models: Differences, 
similarities and interpretational possibilities regarding Tsagaropoulos’ 
model and Tanaka’ s model”, Journal of Electrical Engineering, Vol. 61, 
No. 4, pp. 241-246, 2010 

[5] G. Melissinos, M. G. Danikas, “On polymer nanocomposites: Electrical 
treeing, breakdown models and related simulations”, Engineering, 
Technology & Applied Science Research, Vol. 8, No. 2, pp. 2627-2632, 
2018 

[6] T. Tanaka, T. Imai, “Advances in nanodielectric materials over the past 
50 years”, IEEE Electrical Insulation Magazine, Vol. 29, No. 1, pp. 10-
23, 2013 

[7] S. C. Kechagia, M. G. Danikas, R. Sarathi, “Water droplets and 
breakdown phenomena on polymer nanocomposite surfaces under the 
influence of uniform electric fields”, Malaysian Polymer Journal, Vol. 8, 
No. 2, pp. 41-48, 2013 

[8] R. Gorur, “High voltage outdoor insulation technology”, Control and 
Dynamic Systems, Vol. 44, pp. 131-191, 1991 

[9] M. G. Danikas, “Surface phenomena on resin-type insulators under 
different electrical and non-electrical stresses in the early stage of 
ageing”, Facta Universitatis, Vol. 13, No. 3, pp. 335-352, 2000 

[10] R. S. Sahu, Understanding the electrical, thermal and mechanical 
properties of epoxy nanocomposites, Ph.D. Thesis, Indian Institute of 
Technology Madras, Department of Electrical Engineering, Chennai, 
India, 2007 

[11] R. Sarathi, M. G. Danikas, “Understanding discharge activity due to 
water droplet in epoxy nanocomposites using acoustic emission 
technique”, Journal of Electrical Engineering, Vol. 59, No. 6, pp. 294-
301, 2008 

[12] A. Bairaktari, M. G. Danikas, X. Zhao, Y. Cheng, Y. Zhang, “Behavior 
of water droplets under the influence of a uniform electric field in 
nanocomposite samples of epoxy resin/TiO2”, Engineering, Technology 
& Applied Science Research, Vol. 3, No. 5, pp. 511-515, 2013 

[13] J. H. Mason, “Discharges”, IEEE Transactions on Electrical Insulation, 
Vol. 13, No. 4, pp. 211-238, 1978 

[14] M. S. Naidu, V. Kamaraju, High Voltage Engineering, McGraw-Hill 
Publishing, 2000  

[15] A. A. Hossam-Eldin, S. S. Dessouky, S. M. El-Mekkawy, R. A. Abd El-
Aal, “Internal discharge in cavities in solid dielectric materials”, Journal 
of Electrical Engineering, Vol. 9, No. 4, pp. 1-5, 2009  

[16] M. Kozako, R. Kido, T. Imai, T. Ozaki, T. Shmizu, T. Tanaka, “Surface 
roughness change of epoxy/TiO2 nanocomposites due to partial 
discharges”, 2005 International Symposium on Electrical Insulating 
Materials, Kitakyushu, Japan, June 5-9, 2005 

[17] S. K. Kechagia, Flashover phenomena on the surface of nanocomposite 
materials under the influence of uniform electric fields, MSc Thesis, 
Democritus University of Thrace, 2010 (in Greek) 

[18] J. K. Nelson, Y. Hu, “Nanocomposite dielectrics – Properties and 
implications”, Journal of Physics D: Applied Physics, Vol. 38, pp. 213-
222, 2005 

[19] C. Kalaivananand, S. Chandrasekar, “Understanding inception and 
propagation of electrical tree discharge characteristics in XLPE 
nanocomposites”, The Journal of CPRI, Vol. 13, No. 1, pp. 111-116, 
2017 



Engineering, Technology & Applied Science Research Vol. 9, No. 4, 2019, 4315-4321 4321 
 

www.etasr.com Verginadis et al.: Study of The Phenomena of Surface Discharges and Flashover in Nanocomposite … 

 

[20] M. G. Danikas, T. Tanaka, “Nanocomposites – A review of electrical 
treeing and breakdown”, IEEE Electrical Insulation Magazine, Vol. 25, 
No. 4, pp. 19-25, 2010 

[21] E. David, M. Frechette, “Polymer nanocomposites – major conclusions 
and achievements reached so far”, IEEE Electrical Insulation Magazine, 
Vol. 29, No. 6, pp. 29-36, 2013 

[22] B. X. Du, J. Li, Q. Du, M. L. Fu, “Surface charge and flashover voltage 
of EVA/CB nanocomposite under mechanical stresses”, IEEE 
Transactions on Dielectrics and Electrical Insulation, Vol. 23, No. 6, pp. 
3734-3741, 2016 

[23] S. Yu, S. Li, S. Wang, Y. Huang, M. Tariq Nazir, B. T. Phung, “Surface 
flashover properties of epoxy based nanocomposites containing 
functionalized nano-TiO2”, IEEE Transactions on Dielectrics and 
Electrical Insulation, Vol. 25, No. 4, pp. 1567-1576, 2018 

[24] W. Yan, Nanocomposite dielectric materials for power system 
equipment, PhD. Thesis, University of New South Wales, 2013 

[25] P. A. Sharad, K. S. Kumer, “Application of surface-modified XLPE 
nanocomposites for electrical insulation – Partial discharge and 
morphological study”, Nanocomposites, Vol. 3, No. 1, pp. 30-41, 2017 

[26] M. Liang, Long-term performance of nanocomposite in power 
transmission and distribution systems, PhD Thesis, RMIT University, 
2018 

[27] S. Maslougkas, M. G. Danikas, “Study of water droplets behavior on 
electrical machine insulation under the influence of uniform electric 
fields: The influence of some parameters on mica sheets”, Engineering, 
Technology & Applied Science Research, Vol. 8, No. 1, pp. 2351-2355, 
2018 

[28] L. Zevgolas, Y. Cheng, M. G. Danikas, R. Sarathi, “Study of the 
behavior of water droplets under the influence of a uniform electric field 
in epoxy resin samples having different wt% percentages of 
nanoparticles and microparticles”, Journal of CPRI, Vol. 13, No. 1, pp. 
1-6, 2017  

[29] R. Sarathi, V. Sri Harsha, N. J. Vasa, “Water droplet initiated discharges 
on epoxy nanocomposites under DC cvoltages”, IEEE Transactions on 
Dielectrics and Electriocal Insulation, Vol. 23, No. 3, pp. 1743-1752, 
2016