1. APTRANSCO
Wadapally 132/33 kvSS
100% Reliability Against Contamination Induced Flashovers
with Dow Corning Sylgard HVIC + Coating
By Project Sales Corp, Visakhapatnam
Some Application Pictures

2. 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 the
surface 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 leakage
currents 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 in
AP due to many large cement plants located in the
district which draw power from this industrial feeder
sub-station. Please note the build-up also seen on
conductor wires. Cleaning of these regularly is neither
a feasible nor a cost-effective solution.
In the coming slides, you will see pictures of Sylgard
HVIC+ application onto these equipments. Sylgard
HVIC+ is a proven cost-effective long-term
maintenance free solution to prevent contamination
build-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.

3. Wadapally 132 kvSS and India Cements Plant in the
Background
India Cements plant in the background. The APTRANSCO Wadapally 132 kvSS located in the
premises exposes the sub-station to the cement and other raw material dusts, which settles on the
insulator 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.

4. 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 isolators
arranged and kept in the verandah. Interestingly picture 6 shows the composite strings procured by
APTRANSCO kept at Wadapally SS waiting erection. Note the similarity in the look on the surface of
the composite rubber and Sylgard HVIC+ coated equipment.

5. 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 application
period at Wadapally 132 kvSS. Some pictures here show the water forming into droplets. This does
not allow the wetting of the insulator surface or formation of continuous conductive film on the
surface.

6. 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 subsequently
erected, some of the equipment at Raasi feeder was coated while the Sylgard HVIC+ coated
equipments were getting erected ensuring no downtime for the application.

7. 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 at
Wadapally 132/33 kvSS. These coated discs were subsequently strung on the towers by the erection
contractors. 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. Sylgard HVIC+ Coated Equipments at Wadapally 132 kvSS
at evening time
Sylgard HVIC+ on
equipments at Raasi
and Chanakya
feeders.
The Sylgard HVIC+
coated equipments
offer a breathtaking
site during the
evenings with the
floodlights in the
substation.
Isolators, CTs,
Lighting Arresters,
PTs, and bus-
strings were all
coated ensuring
100% reliability
against
contamination
induced flashovers
for these critical
feeder bays.