Asian Experience With Rtv Silicone Coatings

Asian Experience with
RTV Silicone Coatings
for Insulators
Case Histories

Paper Presented at INMR Hongkong 2005 by Project Sales Corp. mailto:satish@projectsalescorp.com

Abstract
Review RTV silicone coating experiences for high voltage
porcelain insulators in Asian countries such as Korea,
China, Taiwan, Thailand and India.

Focus on case histories of field application of RTV Silicone
Coatings in these countries.


The Flashover Process
Accumulation of Contaminants
(Salt particles from coastal environment/ industrial pollution)
+
Water Filming
(light rain, dew, heavy fog)

Leakage Currents

Dry-band Arcing & Flashover


Cost of Flashovers
Loss of revenue
Disruption of business
Disruption of service
Inconvenience to consumers
Poor service provider image


Flashover Protection Methods
Cleaning
Manual wiping or energized washing with high pressure
systems.
Repetitive short-term solution.
Cleaning must be repeated at a rate that will stay ahead of
the contamination in order to be effective


Design
Extended creepage distance insulators/ Units designed for a
high voltage class.
When pollution problem is known before equipment is
specified.
More often pollution levels are not known or pollution comes
after the construction of the utility system.


Surface Modification
Modify the surface properties of the insulator with the use of
silicone greases and coatings.
Silicones imparts hydrophobicity to the insulator surface that
prevents a conductive film to be formed, thereby limiting and
managing surface leakage currents.
Additives used in the formulation suppress arc and control
surface temperatures.


RTV Silicone Coating
Developed by Dow Corning between 1970-74 as a response
to industry’s need for a maintenance free solution.

Extensively tested at various utilities across the United
States between 1974-84.

Commercially available since 1984 as Sylgard® HVIC.

Global Applications across United States, Europe, Middle
East and Asia in voltage ranging from 11kV to 500 kV DC.


How RTV Silicone Coating Works ?
Imparts hydrophobicity and prevents wetting of contaminants
and formation of an ionisable solution that can lead to
increased leakage, dry band arcing and eventual
flashovers.

Low molecular weight silicone molecules encapsulate
contaminants and neutralize them.

In extreme weather events, arc resistance fillers, ATH
releases H2O and resists degradative effects of high
temperatures.


Review Of
Silicone RTV Coating Installations
Across Asia
Few Case Studies


Sylgard HVIC at 400 kvSS in India

Customer:
State Power Utility

Location:
South India

Pollution:
Salt particles from cooling tower of a thermal power plant. Very
frequent flashovers

Solution:
Sylgard® HVIC applied in 2004 on all equipments in one bay at
the 400 kvSS



All equipments in one bay
of the 400 kVSS, incl. CTs,
CBs, Pilots, Suspension,
Pantograph Isolators,
Supports, etc coated with
Sylgard HVIC


Sylgard HVIC Applied to Transformer Bushings at
Taiwan Power Company

Customer:
Taiwan Power Company Din - Hu
Substation

Location:
LinCo, Taipei County, North West
Region of Taiwan

Pollution:
Saline, smog, industrial and
chemical pollution

Solution:
Sylgard® HVIC applied in 1993
continues to perform until 1999


Sylgard HVIC Applied to Transformer Bushings at
Taiwan Power Company

Substation started operation in Substation wanted a long-term
1988 maintenance free solution.
Situated near the coast exposed Sylgard HVIC applied on 345 kV
to saline environments as well as transformer bushings in 1993.
industrial and chemical Washed them in 1996 during third
pollutants. year inspection.
Weekly washing in the first few Continued to perform until 1998.
years of operation. Recoated with Sylgard HVIC
Applied Silicone Grease in 1992. 0.25mm thick in 1999.


Sylgard HVIC at Hsinchu Industrial Park 68 kV Substation

Customer:
Taiwanese Power Utility – Hsinchu Industrial Park Substation

Location:
Hsinchu Industrial Park, Taiwan

Pollution:
Dust, salt deposits and chemical pollution

Solution:
Sylgard® HVIC applied in 1993 continues to perform.


Sylgard HVIC at Hsinchu Industrial Park
68 kV Substation

Substation located 10 km from Entire substation coated including
ocean. support and suspension
Serves Industrial customers insulators, bushings, etc with
including large manufacturing Sylgard HVIC in 1993.
plants. Sylgard HVIC sprayed over a
Used Silicone Compound but week in two stages – 8 hours
found shutdown for repetitive each.
application difficult. No flashovers since 1993. Sylgard
Started energized washing HVIC continues to perform.
weekly but experienced
flashovers during and between
washing.


Shanghai Extra High Voltage Power Transmission
Company

500kV Nanqiao HVDC Converter station,
wall bushings coated with Sylgard HVIC.

This line links central and eastern network
(Yangtze to Shanghai).

HVDC creates special problem.
Contaminated particles get polarized and
attract to the insulators.

Converter stations are located at each end of the line. Light
industrial and river pollution necessitated continual hand
cleaning of the HV DC insulators until the application of
Sylgard® HVIC coating in 1991


Bhutan Power Station 220/132 kVSS
Customer:
Pashaka Substation 220/132 kVSS

Location:
Bhutan

Pollution:
Slurry from land slides, carbide dust from
carbide plant, cement dust from cement
plant

Problem:
Frequent tripping and repeated
shutdowns to clean 220 kv support
insulators and isolator switches.

Solution:


Cement Plant, North India 132/33 kVSS

Customer:
Gujarat Ambuja Cement 132/33 kV
SS

Location:
North India

Pollution:
Captive Dust; Fly Ash from adjacent
thermal plant

Problem:
Frequent tripping and shutdowns to
clean insulators

Solution:


Gujarat, West India, Petrochemicals Complex 220kv SS

Customer:
Reliance Petrochemicals

Location:
Gujarat, West India

Pollution:
Iron Ore Dust from a neighboring steel plant, captive dust and saline
environment

Problem:
Shutdowns to regularly clean insulators was difficult; CT Failure

Solution:
Sylgard® HVIC applied in 2000 on CTs and other critical equipment


What kind of approach would you use ?


Trend Towards RTV Coating in Power Utilities
Utilities gradually moving from water washing and greasing
to one time application of Silicone RTV Coating for
installed equipments.

Silicone RTV coating has proven as a very cost-effective
protection method.

Internal study of 132 kv SSs in a state utility in India –
(i) The cumulative revenue losses from outages over a
period 3 years is almost equal to the investment in Sylgard
HVIC coating. (ii) It also works to approx. 1% of annual
revenue of the sub-station. With better reliability vis-à-vis
other methods.


RTV Silicone Coating in Taiwan and China

Year Customer Voltage Contaminant
1989 Ge Zhou Ba Power Plant 500 kV DC Industrial pollution
1989 Nan-Pu Power Plant 161 kV Salt, dust
1990 Hsin- Tao Substation 69 kV Salt, dust
1990 Mai-Laio Transmission line 69 kV Salt
1990 Ta-Lin Power Plant 161 kV Salt, Industrial
1990 Sang-Min Power Plant 161 kV Salt, Industrial
1991 Sang-Yang Motor Company 69 kV Industrial, dust
1991 Taiwan Styrene-Petrochemical Plant 69 kV Industrial, dust
1991 Taiwan Glass 69 kV Salt, industrial
1991 Fang-Liau Substation 69 kV Salt
1991 Fang-San Substation 69 kV Salt
1991 Taichung Transmission Lines 345 kV Salt
1992 Chung-Mei-Ho Power Plant (petrochemical) 69 kV Salt, Industrial

1993 Hseih-ho Power Plant 69 kV Salt
1993 Lin-Co Substation 345 kV Salt
1993 Taichung Power Plant 345 kV Salt
1994 Shen-au Power Plant 161 kV Salt


RTV Silicone Coating in Thailand

1993 TPI Petrochemical Public co. Ltd 11 kV Industrial pollution

1993 MEA Transmission Line 69 kV Pollution

1994 Thai Asahe 69 kV Sodium hydroxide/others

1994 Thai Central Chemical 69 kV Phosphate/others

1994 Nagyang Factory Co Ltd 22 kV Industrial pollution

1994 Charernsawat CoLtd 22 kV Industrial pollution

1994 Nakornluang Cement 115 kv Pollution

1995 Phadaeng Industry Public Co 230 kV Salt, industrial

1995 Egat ( Switchyard Bay 1 - 6 ) 230 kV Salt, industrial


1995 Magtric Co Ltd 22 kV Industrial pollution

1995 Siam Tire cord Co Ltd 22 kV Industrial pollution


1996 KR Precision Public Co Ltd 22 kV Industrial pollution

1996 Thai Caprolactam Public Co Ltd 115 kV Lignite, Chemical

1996 Egat Substation 115 kV Salt, industrial




1996 Egat CC&CC Block 1 & 2 230 kV Salt, industrial


RTV Silicone Coating in Korea


1995 KEPCO (Suncheon Power Station) 154 kV Industrial

1997 Namdong Power plant (Samcheonpo) 345 kV Salt, dust

1998 Dongseo Power plant (Ulsan petro) 345 kV Salt, dust

2000 Hyundai Mipo (Ship building Co.) 154 kV Salt, dust

2001 KERI 154 kV Industrial

2001 KEPCP (Jinju Power Station) 345 kV Salt, Industrial

2002 Nambu Power Plant (Hadong petro) 345 kV Dust

2002 Youngkwang Nuclear Plant 345 kV Salt, dust

2002 Kumho Power Plant 154 kV Salt, industrial

2003 KEPCO (Sin-Ulsan) 345 kV Salt

2003 KEPCO (Sin-Goyang) 345 kV Salt

2003 Nambu Power Plant (Youngnam petro) 154 kV Salt

2003 Seobu Power Plant (Pyungtaeck) 154 kV Salt, Industrial

2003 Uljin Nuclear Power Plant 345 kV Salt

2004 KEPCO (Suwon Power Station) 345 kV Salt

2004 Gori Nuclear Power Plant 345 kV Salt

2004 Wolsung Nuclear Power Plant 345 kV Salt

2005 Dongseo Power plant (Dangjin petro) 345 kV Salt


To Conclude
After its commercial introduction in 1984, hundreds of
installations have been successfully coated in Asia and
worldwide with Sylgard® HVIC, the brand from Dow
Corning.
In particular, Asian installations now have a proven
alternative to mitigating contamination related flashovers.
Sylgard® HVIC has successfully avoided flashovers in most
kinds of pollution and weather environments.
Sylgard® HVIC is a cost-effective method to prevent
contamination induced flashovers..


Special Thanks
Mr. Venkatraman Sundaramoorthy, Sales Manager, EEI,
Dow Corning India (P) Limited, India

Mr. Nitin Kamat, Industry Sales Manager, HVIC, Dow
Corning India (P) Limited, India


Thank you


Asian Experience With Rtv Silicone Coatings

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