8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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APTRANSCOAPTRANSCOWadapally 132/33 kvSSWadapally 132/33 kvSS100% Reliability Against Contamination Induced Flashovers100% Reliability Against Contamination Induced Flashovers

with Dow Corning Sylgard HVIC + Coatingwith Dow Corning Sylgard HVIC + Coating

By Project Sales Corp, VisakhapatnamBy Project Sales Corp, Visakhapatnam

Some Application PicturesSome Application Pictures

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Wadapally 132 kvSS equipments before application of

Rationale for application of Sylgard HVIC+Wadapally 132 kvSS, located in the India Cement

premises at Wadapally, Damacherla Mandal,Nalgonda District. The pictures shows the various

levels of contamination and depositions on thesurface of the insulators at site. Cement, gypsum and

other dusts bonds onto high energy porcelain

surfaces making their cleaning difficult.

The contaminated surfaces leads to surface leakagecurrents during rains or early morning dew, develops

into dry bands and arcing and leads to eventual

flashovers resulting in the loss of revenue to

APTRANSCO as well as customer dis-satisfaction.

Wadapally is among the high revenue sub-stations inAP due to many large cement plants located in thedistrict which draw power from this industrial feeder

sub-station. Please note the build-up also seen on

conductor wires. Cleaning of these regularly is neithera feasible nor a cost-effective solution.

In the coming slides, you will see pictures of SylgardHVIC+ application onto these equipments. SylgardHVIC+ is a proven cost-effective long-term

maintenance free solution to prevent contaminationbuild-up and wetting of the insulator surface. Its low

molecular weight silicones also ensure contamination

particles seating on the insulator surface do not wet

and form a conductive solution thus interrupting the

flashover process at an early stage.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Wadapally 132 kvSS and India Cements Plant in the

Background

India Cements plant in the background. The APTRANSCO Wadapally 132 kvSS located in thepremises exposes the sub-station to the cement and other raw material dusts, which settles on theinsulator surface, and during light rains or early morning dew these contamination gets wetted and

forms a conductive solution resulting in leakage currents, dry bands and eventual flashovers.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Isolator Switches being coated with Sylgard HVIC +

at Wadapally 132 kvSS

132 kv Isolator Coating in progress in pictures 1-3. Picture 4 and 5 shows the coated isolatorsarranged and kept in the verandah. Interestingly picture 6 shows the composite strings procured byAPTRANSCO kept at Wadapally SS waiting erection. Note the similarity in the look on the surface ofthe composite rubber and Sylgard HVIC+ coated equipment.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Hydrophobic Behavior on surface of Sylgard HVIC+

coated insulators at Wadapally 132 kvSS after a rain

The hydrophobic behavior of Sylgard HVIC+ could be witnessed after a rain during the applicationperiod at Wadapally 132 kvSS. Some pictures here show the water forming into droplets. This doesnot allow the wetting of the insulator surface or formation of continuous conductive film on thesurface.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Raasi Feeder during and after the coating of all equipments

with Sylgard HVIC+

While most of the Sylgard HVIC+ application were done on new equipments which were subsequentlyerected, some of the equipment at Raasi feeder was coated while the Sylgard HVIC+ coated

equipments were getting erected ensuring no downtime for the application.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Trafo Bushings in-situ and bus strings (new discs) at

Wadapally 132 kvSS Coated with Sylgard HVIC +

Over 300 discs were coated with Sylgard HVIC+ to be installed in the 132 kv and 33 kv side atWadapally 132/33 kvSS. These coated discs were subsequently strung on the towers by the erectioncontractors. The trafo bushings were cleaned with IPA, primed and coated with Sylgard HVIC + in-situ

while the 33 kv equipment erection was in progress.

8/14/2019 100% Reliability Against Contamination Induced Flash Overs at APTRANSCO 132 KvSS Wadapally Andhra Pradesh India

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Sylgard HVIC+ Coated Equipments at Wadapally 132 kvSS

at evening time

Sylgard HVIC+ onequipments at Raasiand Chanakya

feeders.

The Sylgard HVIC+coated equipmentsoffer a breathtakingsite during theevenings with the

floodlights in thesubstation.

Isolators, CTs,Lighting Arresters,PTs, and bus-strings were all

coated ensuring100% reliabilityagainstcontaminationinduced flashoversfor these criticalfeeder bays.