Mitigating Contamination Related Issues on T&D Equipment. Lily Hoyer Simon Chan

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1 Mitigating Contamination Related Issues on T&D Equipment Lily Hoyer Simon Chan

2 Substation Insulator Pollution Contamination Management

3 PRESENTED BY LILY HOYER T&D ASSET MANAGEMENT ENMAX POWER CORPERATION Contents INTRODUCTION ENMAX INSULATOR FLASHOVER STATISTICS PRESENTED TO 2012 APIC POWER AND ENERGY INNOVATION FORUM MITIGATION MANAGEMENT PILOT PROJECT CONCLUSION

4 INTRODUCTION OF INSULATOR CONTAMINATION Insulator: isolation from the energized high voltage bus to ground Insulator pollution contamination 4

5 How does your car look in winter? Road salt on the car 5

location) Industrial areas: fly-ash, variety of dust Agricultural areas: soil dust, fertilizers Highways: salt from

6 INTRODUCTION OF INSULATOR CONTAMINATION Insulator flashover: surface discharge when moisture condenses on solid insulation subject to particulate pollution Factors of insulator flashover: Moisture condensation Pollution (By location) Industrial areas: fly-ash, variety of dust Agricultural areas: soil dust, fertilizers Highways: salt from roads during winter time By components: Soluble: Salt or Sodium Chloride Non-Soluble: Calcium Chloride, carbon, and cement dust ect. 6

7 INTRODUCTION OF INSULATOR CONTAMINATION Sequence of events leading to flashover Deposit of pollution on the insulator surface Surface layer is moistened by fog, misty rain Surface layer is heated Heating results in local drying and dry bands formed Partial arc occur across dry bands Increased partial discharge Partial discharges are connected to a complete flashover Video of the surface discharge 7

8 ENMAX EXPERIENCE OUTAGE STATISTICS CAUSED BY INSULATOR FLASHOVER 2008 with most interrupted customers and longest interruption duration Average Interruption time in minutes has significantly reduced since 2009 # of Customers Interrupted Year Average Interruption 30 Duration (min.)

9 MITIGATION MANAGEMENT Time based preventive maintenance program Review and enhance our substation washing program (Sub washing committee was formed in 2008) Meets twice a year to review frequencies Analyzes past year s sub washing for effectiveness Corrective maintenance program Visual inspection Anticipation of the contamination (weather condition change) 9

10 SUBSTATION WASHING PROGRAM IN DETAIL Factors of determining sub washing frequency Location of the sub (near high way, industry, river, land elevation) Area external to the sub (construction, type of roads) Past history of insulator flashover Type of insulators (polymer, porcelain) Type of bus (H bus-water drainage) Insulator hats are installed (prevent water drops freezing from skirt to skirt) Criticality of the sub (control center input) Management and Field input 10

11 H bus vs. Round bus

12 Types of Insulator in Enmax Porcelain Silicone covered porcelain Polymer

13 Substation Washing types High pressure washing Flood washing Corn blast washing Hand wash

14 Washing Experience hand wash Scratches on silicone coated porcelain insulator by hand wash

15 Washing Experience Polymer seam Seam of polymer insulators introduced in manufacturing process

16 Substation Washing types vs. Insulator type High pressure washing Flood washing Corn blast washing Hand wash Porcelain Insulators Silicon coated Insulators Polymer Insulator

17 # of Substations Substation Wash Schedule Washing schedule Distribution of Sub Washing Frequency 2/year 1/year 1/2 years 1/3 years 1/4 years Washing Frequency Ongoing review of the washing frequency

18 PILOT PROJECT DOBLE IPM Initialized in 2009 to utilize condition monitoring of pollution severity based on leakage current Installed Doble IPM in Fall 2010 on one substation next to highway and river

19 PILOT PROJECT DOBLE IPM Location

20 20 DOBLE IPM METHODOLOGY

21 21 LOCATION OF THE CURRENT SENSOR 138 kv

22 22 CURRENT SENSTOR MOUNTING LOCATION

23 23 DOBLE IPM METHODOLOGY

24 Evaluation of Pollution Level High cumulative charges + High peak currents (with high counts) High level of pollution Dry & polluted insulator -> lower peak current; Foggy, high humidity morning -> Flashover??? 24

25 Imax Calculation Maximum peak leakage current is defined as Imax= (SCD/15.32)^2 SCD_138 = /145 = 17mm/kV SCD: Specific Creepage Distance in mm/kv KV is the maximum phase to phase voltage 138kV insulator: Creepage distance is 99 inch. Guideline for peak leakage current threshold value is set at 25% of Imax I_138_threhold = 308 ma (???) 25

26 DOBLE IPM LEAKAGE CURRENT MEASUREMENT Plot from Jan April

27 DOBLE IPM LEAKAGE CURRENT MEASUREMENT March 15, 2012 Substation wash 27

28 Doble IPM EXPERIENCE Limitation in Leakage current method in Calgary winter (dry and heavy polluted insulator -> small leakage current) Benchmark is not available (Doble threshold value too high) Lack of Doble support 28

29 Conclusions Washing committee enhanced sub washing program: less flashover outages and duration of outage decreases Equipment upgrade is ongoing: H bus replacement, porcelain insulator replacement Leakage current detection: correlation to relative humidity, ESDD (equivalent salt deposit density) tests 29

30 enmax.com Change this under "View" menu, Header/Footer options

31 PRESENTED BY SIMON CHAN T&D ASSET MANAGEMENT ENMAX POWER CORPERATION I Contents EFFECTS OF CONTAMINATION PRESENTED TO 2012 APIC POWER AND ENERGY INNOVATION FORUM MITIGATION METHODS

32 Questions?? Change this under "View" menu, Header/Footer options

33 Effects of Contamination Effects of contamination include: Flash Over on Equipment (Equipment failure) Electrical Tracking (Wood Pins, Cross Arms) Pole Fires Material Failures (Automatic Sleeves) Exterior Rusting, peeling of paint. Consequences Poor reliability Safety $$$ 33

34 Equipment/Material Flashover Padmount Switchgear Rusting, peeling of paint on exterior. Higher risk of flashovers 34

35 Electrical Tracking Wood Pins Androlite Arms Wood Cross Arms Insulators 35

36 36 Wood Pin

37 37 Androlite Arms

38 Pole Fires Pole fires caused by contamination can only occur under the following conditions: Leakage current from energized equipment. Heat

39 Road Salt vs Pole Fires

40 MITIGATION METHODS Androlite Conversion Insulator Washing Switch Cleaning Material Standard Change Pole Fire Mitigation Program Wood Pin Program Padmount Painting/Exterior Replacement 40

41 Androlite Conversion Flattening Androlite Configuration to Current Construction Standards

42 Insulator Washing Maintenance Program EPC initiated a multi-year insulator washing maintenance program. Priority is on City of Calgary Priority One sanding routes. Extra emphasis on areas where pole fires occurred previously. Twice a year cycle. Late March to early April. Late September to early October

43 Insulator Washing Maintenance Program

44 Pad Mount Switch Dry Ice Cleaning Contaminants have caused flashovers to Live Front Pad Mount Switch Gear. EPC has implemented a 5 year inspection and dry ice cleaning cycle for switches. EPC is exploring possibilities of dry ice cleaning for Distribution Automation Pad Mounted Switches.

45 Material Standard Changes Porcelain to Polymer Porcelain insulators Over insulated 34 kv polymer insulators. Change to Porcelain Fused Cut Outs and lightning arrestors to Polymer. Cross Arms (Wood to Fiber glass) Fiber glass replaces deteriorated wood crossarms.

46 Material Standard Changes

47 Material Standard Changes

48 Material Standard Changes Cut Outs 48

49 49 Splices

50 Splices Automatic to Compression Sleeves Initial samples Corrosion found. Corrosion was more evident near major roadways. In 2011, only compression splices are to be used for all new construction and repair work. Ongoing further investigation of automatic splices. 50

51 Pole Fire Mitigation Program In 2001, EPC initiated a multi-year over-insulation and insulator washing maintenance program. A total of $.57M were spent in the next seven years ( ). No structures that had been mitigated with upgraded insulation have been involved in pole fires.

52 Pole Fire Mitigation Program EPC has seen an increase in contamination of the distribution overhead structures. In 2008, there were 76 pole fire incidents causing nearly customer interruptions and significant customer interruption time.

53 53 Pole Fire Locations

54 Incidents Pole Fire Mitigation Program 80 Pole Fires (YTD) Year

55 Pole Fire Mitigation Program Alternatives Considered 1) Do nothing 2) Dry Ice Washing 3) Bonding 4) Over Insulation

56 Pole Fire Mitigation Program Over Insulation Wood crossarm Fiberglass crossarm Porcelain insulator 34 kv class polymer insulator Porcelain cutout Polymer cutout

57 Pole Fire Mitigation Program

58 Pole Fire Mitigation Program Current Progress Primarily focus is on mitigating overhead structures with equipment only. Mitigated nearly 70% of these structures. Expected completion 2014.

59 59 POLES MITIGATED

60 Wood Pin Program Prevalent standard of insulator support until early 1970s when steel pins become industry standard. Increased risk to the safety of the general public and EPC employees. Minimize hazards.

61 Wood Pin Program Material Change Wood pins to Steel Pins Contamination due to road salt increased rate of deterioration in wood pins due to electrical tracking.

62 Wood Pin Program Started in 2008 Nearly 4000 Structures containing wood pin to replace. Expected completion in 2014.

63 Equipment Painting/Exterior Replacement Existing Padmount Painting Program Typically pad mounted equipment a year. Severe deterioration Replacement of doors and tops 63

64 Questions?? Simon Chan, Lily Hoyer, Change this under "View" menu, Header/Footer options

CO 2 Cleaning and Its Effectiveness in Cleaning Energized Medium-Voltage Equipment

CO 2 Cleaning and Its Effectiveness in Cleaning Energized Medium-Voltage Equipment Abstract This paper provides an overview of how CO 2 cleaning works on energized electrical equipment. It also presents