Si-COAT 570 RTV Silicone HVIC. Reliability & Beyond. Seminar Presentation

Transcription

1 Si-COAT 570 RTV Silicone HVIC Reliability & Beyond Seminar Presentation

2 Overview Background & industry pressures Early validation of Si-COAT HVIC The science of Si-COAT Q&A

3 Si-COAT HVIC : The Background A need for a robust insulator coating Excellent adhesion required Elimination of water washing required Si-COAT Formulated for: Superior adhesion Very smooth surface finish Extremely long life Two very surprising advantages discovered!

4 Si-COAT : The Advantages One-part RTV (ready-to-use) Superior adhesion Smooth surface finish Rich LMWS concentration Low surface free energy Very high hydrophobicity Maintenance free Near total suppression of leakage current

5 A Thorn in Reliability s Side Insulator contamination : a long posed nuisance Water washing Short-term solution Greasing Short-term solution Composite insulators Questionable reliability RTV Silicone Coatings Reliable performance Leverages mechanical integrity of ceramics A cure for ailing composites

6 Si-COAT versus Water & Grease 250 Cumulative Expense Water Grease Si-COAT 0 Year 0 Year 2 Year 4 Year 6 Year 8 Year 10

7 Si-COAT : a Remarkable Effect Leakage current nearly eradicated LABORATORY Zittau University (Germany) Testing IEC Salt Fog Test; 1,000 hours KEMA (Netherlands) Testing IEC Salt Fog Test; 5,000 hours FIELD US Dept. of Energy > 99% suppression over 10 years PPC Greece > 99.9% suppression in IEC Class IV contamination zone Kinectrics Research 20 kw/km recoverable! Koeberg (KIPTS) Testing

8 IEC : 1,000 hr Si-COAT Result Test Parameters Medium voltage porcelain mm creepage - 60 mm core diameter mm shed diameter mm dry arc resistance 20.3 kv ; 0.29 kv/cm 6.7 ms/cm fog conductivity (ref. 50 ms/cm for sea water) Observation Max leakage current of <0.1 ma Data : Prof R. Bärsch, HV Lab, Zittau University of Applied Sciences

9 IEC : Si-COAT Shines Final Test Report, KEMA Laboratories, The Netherlands, 2004

10 Si-COAT HVIC Thermal Imaging in Rural Italy Thermal imaging via infrared cameras measures the rise in temperature, above ambient, of various structures. Since leakage current generates heat, thermal imaging is an ideal and costefficient tool to measure approximate levels of leakage current. Thermal imaging by infrared cameras of insulators coated with Si-COAT and those left uncoated reveal that uncoated insulators undergo an appreciable rise in temperature. Each Celsius degree rise in temperature above ambient roughly correlates to 2 ma of leakage current. Si-COAT HVIC coated insulator (at ambient temp.) Uncoated insulators (at elevated temp.) The approximate 9 C temperature rise of uncoated sections in this photograph indicate roughly 18 ma of leakage current on uncoated insulators. Coated insulators show no rise in temperature, translating to an effective zero level of leakage current. Photo courtesy of Terna of the Enel Group, Italy

11 US Dept. of Energy Experience Columbia Generating Station 1,150 MW Nuclear Plant Owned & operated by Energy Northwest Sole customer is Bonneville Power Administration (US Dept. of Energy) East side of Washington State Seemingly unlikely place for insulator contamination

12 (US DoE) : Plant Configuration

13 (US DoE) : Plant Configuration Transformer yard on north side of station

14 (US DoE) : Contamination Issues south north Prevailing winds from south Plume & contaminants carried to transformer yard

15 (US DoE) : Contamination Issues Condensed plume migrating north to transformer yard

16 (US DoE) : Contamination Issues Typical contamination buildup

17 (US DoE) : Contamination Issues Cooling water drawn from Columbia River Contamination sources Natural river contaminants Buffer chemicals Contaminants in circulation water Anions: sulphate, bicarbonate, silica, chloride, orthophosp hate, fluoride Cations: calcium, magnesium, sodium, ammonia, copper, zi nc, iron

18 (US DoE) : Failure in Reliability Flashover #1: 17h14, 30-January-89 Plume condensed in cold Corrective action: annual water washing Flashover #2: 10h10, 10-December-90 Corrective action: find the correct solution

19 (US DoE) : Reliability Investigations I. Cleaning Off-line cleaning Hot line washing Installed insulator washers II. Monitoring Insulator leakage current monitoring Weekly measurement of ESDD Meteorological monitoring RF/Ultrasonic III. Contamination Source Reduction Transformer Yard cover Transformer Yard wind deflectors Drift eliminators Cooling tower plume reduction Hot air ducted into transformer yard IV. Insulator Modifications Fog type insulators Non-ceramic insulators Resistance graded insulators Creepage extenders Silicone grease Si-COAT RTV Silicone HVIC

20 (US DoE) : Si-COAT HVIC Testing Si-COAT under test from 1989 Intensive testing initiated late 1991 Principal property was to improve hydrophobicity (prevent water filming)

21 (US DoE) : Si-COAT HVIC Testing Fog Chamber Tests Round 1 (31-Dec-92) Coated & uncoated insulators first contaminated for 3 months under plume ESDD up to mg/cm 2, area weighted avg. Trial #1 Trial #2 Minutes to Flashover Per Unit Rated Voltage Minutes to Flashover Per Unit Rated Voltage Bare Other RTV Si-COAT RTV > >

22 (US DoE) : Si-COAT HVIC Testing Fog Chamber Tests Round 2 (05-May-93) 31.5 in station post insulators Exposure: 20 days tower mist and 26 lbs dust 5 days mist and heat cycling Flashover Voltage Per Unit Rated Voltage Bare 117 kv 1.52 Company 1 RTV 131 kv 1.70 Company 2 RTV 227 kv 2.94 Silicone Grease A 240 kv 3.11 CSL-880 Grease 250 kv 3.25 Si-COAT RTV 251 kv 3.26

23 (US DoE) : Conclusions Si-COAT provided superior results for reducing risk and preventing flashover With the concurrence of US DoE, Energy Northwest determined Si-COAT (CSL) RTV HVIC offered best prospects for preventing future service interruptions

24 (US DoE) : Results Si-COAT virtually eliminated leakage current Maximum Broad-Band Leakage Current 18-Dec-93 Apr-94 Uncoated Insulator 50 ma 100 ma Si-COAT RTV HVIC Coated Insulator < 0.25 ma (> 99.5% suppression) < 0.25 ma (> 99.8% suppression)

25 (US DoE) : Results US DoE Internal Report 03-Jun-94 Si-COAT avoided at least 6 forced outages in first year alone Leakage current, hydrophobicity and resistance testing indicated good condition after 10 years of service Recoat at 10 years as insurance Few visible signs of degradation

26 Si-COAT 570 RTV Silicone HVIC The Science

27 Insulators conditions are not Perfect particles of dirt electrons LEAK along a dirty insulator

28 How Does Si-COAT Work?

29 Si-COAT LMWS Encapsulates Dirt

30 Water Can t Combine with Dirt

31 Si-COAT has Most LMWS Relative bulk LMWS concentrations as revealed by X-ray mapping technique Si-COAT Other RTV HVIC

32 How To Avoid Damage to Silicone! this area gets WARM & DRY

33 How To Avoid Damage to Silicone! Dry band arcing Very high temperatures Can damage unprotected coating

34 Dry Band Arcing Damage is Beaten ATH: Alumina Trihydrate Dry band arcing activates ATH ATH absorbs the energy of dry band arcing Coating is protected and undamaged Surface of ATH particle is most critical The greater the surface area of the ATH, the more protection that is offered

35 Smaller ATH = More Surface Area

36 Very Small ATH Restricts LMWS

37 Larger ATH Promotes LMWS Flow

38 13 microns : Optimum ATH Size The basis of CSL s patent for Si-COAT HVIC is the 13 micron Optimum ATH Particle Size

39 Developing Ultra-Hydrophobicity

40 Ultra-Hydrophobicity Explained Ultra- Hydrophobicity is also known as The Lotus Leaf Effect

41 Ultra-Hydrophobicity Explained

42 Ultra-Hydrophobicity, Turkey (2 years)

43 Ultra-Hydrophobicity, Turkey (2 years)

44 Ultra-Hydrophobicity, Turkey (2 years)

45 In Conclusion 1. The Si-COAT patented technology proposes three levels of value: Maintenance reduction Reliability improvement Economic/Environmental benefits 2. Si-COAT virtually eliminates leakage current for the long term 3. Therefore, significant reduction in expenses and losses due to planned/unplanned outages 4. Investment in Si-COAT very quickly recovered

46 Si-COAT 570 RTV Silicone HVIC Q&A Session Seminar Presentation