Mitigating Contamination Related Issues on T&D Equipment ...apic/uploads/Forum/Mitigating... · Lily Hoyer Simon Chan . PRESENTED BY SIMON CHAN T&D ASSET MANAGEMENT ENMAX POWER CORPERATION

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

PRESENTED BY SIMON CHAN T&D ASSET MANAGEMENT ENMAX POWER CORPERATION

PRESENTED TO

2012 APIC POWER AND ENERGY INNOVATION FORUM

INTRODUCTION

EFFECTS OF CONTAMINATION

MITIGATION METHODS

Introduction

Contamination has a significant impact on Enmax Power Corporation (EPC) Distribution Equipment and Material.

Contamination due to pollution, de-icers/road salt.

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)

Consequences Poor reliability

Safety

$$$

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Equipment/Material Flashover

Padmount Switchgear Rusting, peeling of paint on exterior.

Higher risk of flashovers

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Electrical Tracking

Wood Pins

Androlite Arms

Wood Cross Arms

Insulators

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Wood Pin

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Androlite Arms

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Pole Fires

Pole fires caused by contamination can only occur under the following conditions:

Leakage current from energized equipment must be passed through the wood pole to ground.

Localized leakage current densities must be increased to the point where sufficient heat is generated to begin pole fire process.

Road Salt vs Pole Fires

MITIGATION METHODS

Androlite Conversion

Insulator Washing

Switch Cleaning

Material Standard Change

Pole Fire Mitigation Program

Wood Pin Program

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MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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Flattening Androlite Configuration to Current Construction Standards

MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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Insulator Washing Maintenance Program

EPC initiated a multi-year insulator washing maintenance program acting on recommendations by the Canadian Electricity Association’s “The Prevention of Pole Fires” report.

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 October to early September

Insulator Washing Maintenance Program

MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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PMH Dry Ice Cleaning

Contaminants have caused flashovers to Pad Mount Switch Gear.

EPC has implemented a 5 year inspection and dry ice cleaning cycle for switches.

Currently, EPC is exploring possibilities of dry ice cleaning for Distribution Automation Pad Mounted Switches.

MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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Material Standard Changes

Porcelian 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.




Cut Outs

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Splices

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Splices

Automatic to Compression Sleeves

Initial samples collected from the field were brought to a test lab and found significant corrosion from selected locations.

Corrosion was more evident near major roadways.

In 2011, only compression splices are to be used for all new construction and repair work.

Currently, EPC is collecting additional samples of automatic splices to a test lab for further analysis and will determine whether mechanical reinforcement or replacement with compression repair splices will be the next step.

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MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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In 2001, acting on the recommendation by CEA, “The Prevention of Pole Fires” report, EPC initiated a multi-year over-insulation and insulator washing maintenance program.

A total of $.57M were spent in the next seven years (2001 – 2007) at high pole fire re-occurrence areas to reduce pole fire incidences.

No structures that had been mitigated with upgraded insulation have been involved in pole fires.


The combination of weather as well as an increase of both the traffic and application of de-ice agent (i.e. road salt) has resulted in an increase in contamination of the distribution overhead structures.

In 2008, there were 76 pole fire incidents causing nearly 96000 customer interruptions and significant customer interruption time.


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10

20

30

40

50

60

70

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2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012(YTD)

Incid

en

ts

Year

Pole Fires


Alternatives Considered

1) Do nothing

2) Dry Ice Washing

3) Bonding

4) Over Insulation


Over Insulation

Wood crossarm Fiberglass crossarm

Porcelain insulator 34 kV class polymer insulator

Porcelain cutout Polymer cutout



Current Progress

Primarily focus is on mitigating overhead structures with equipment only.

Mitigated nearly 70% of these structures.

Expected completion 2014.

MITIGATION METHODS


Insulator Washing

Switch Cleaning



Wood Pin Program

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Wood Pin Program

Prevalent standard of insulator support until early 1970s when steel pins become industry standard.

Age and condition of the wood pins pose an increased risk to the safety of the general public and EPC employees.

Replacing to steel pins will minimize the hazards of line faults, pole-fires and line-down incidents associated with wood pin deterioration.

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.

Wood Pin Replacement Project

Started in 2008

Nearly 4000 Structures containing wood pin to replace.

Expected completion in 2014.

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Substation Insulator Pollution Contamination Management

PRESENTED BY LILY HOYER T&D ASSET MANAGEMENT ENMAX POWER CORPERATION

PRESENTED TO

2012 APIC POWER AND ENERGY INNOVATION FORUM

INTRODUCTION: Insulator Contamination?

ENMAX INSULATOR FLASHOVER STATISTICS

MITIGATION MANAGEMENT

PILOT PROJECT

LEARNINGS & CONCLUSION

INTRODUCTION OF INSULATOR CONTAMINATION

Insulator: isolation from the energized high voltage bus to ground.

Insulator contamination

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INTRODUCTION OF INSULATOR CONTAMINATION

Insulator flashover: surface discharge when moisture condenses on solid insulation subject to particulate pollution

Factors of insulator flashover: Moisture condensation

Typical sources of insulator pollution depending on location

Coastal areas: salt from the sea

Industrial areas: fly-ash, variety of dust

Agricultural areas: soil dust, fertilizers, sugar cane production

Highways: salt from roads during winter time

SURFACE CORONA VEDIO AT 31S - 138KV bus trip Mar17-06

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C:/Documents and Settings/Wilsun Xu/Local Settings/Temp/Best.MP4






DAMAGED INSULATOR

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INSULATOR FLASHOVER – CIRCUIT BRAKER FAILURE

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OUR EXPERIENCE – INSULATOR FLASHOVER STATISTICS

YEARS OUTAGE NUMBERS

Prior 2001 3

2002-2006 3

2007 6

2008 2

2009 3

2010 3

2011 2

2012 0

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2007 with a lot of flashover outages

2008 with most interrupted customers and longest interruption

Result in bus outage

MITIGATION MANAGEMENT

Preventive maintenance 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 Visual inspection

Anticipation of the contamination (weather condition change)

Pilot project on condition monitoring of insulator contamination in 2009, installed in Fall 2010

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SUBSTATION WASHING PROGRAM IN DETAIL

Factors of determining sub washing frequency Location of the sub (near high way, industry, river, land elevation) Criticality of the sub (control center input) Area external to the sub (construction, type of roads and speed limit) Type of insulators (polymer, porcelain) Type of bus (H bus-water drainage, Insulator hats are installed Past history Management and Field input

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H bus vs. Round bus

Insulator Hat

Types of Insulator

Porcelain – easiest to track across.

Porcelain silicone – buys time since salt tracking is hampered

Polymer – best for preventing flashovers due to salt and pollution

Substation washing types

High pressure washing – 800psi for porcelain; 500psi for silicon coated porcelain

Flood washing – 300psi

Hand washing

Corn blasting

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High Pressure Washing

Pros • Quicker

• Cheaper

• Best performance

Cons • Contractor availability

• Must be above 5 degrees

• Pushes dirt around insulator and not necessarily cleans it

• Can not wash potheads

• Not applied to porcelain silicone

Flood washing

Pros

• Less over spray

• Cheap

• Can potheads

Cons

• Contractor

• May not get rid of tough contaminants

• Weather dependant

• Pushes dirt around insulator and not necessarily cleans it

• May not get under the skirts

Hand Washing

Pros • Any temperature

Cons • Very costly

• Extra crews

• Longer outage

• Monotonous – poorer job performed as time wears on

• Destroys the silicone on insulators

• Pushes dirty to seams on polymer

Corn Blasting

Pros

• Can do hot

Cons

• Only on lower voltage

• Very messy

• Clean up

• Expensive

• Destroys the silicone on insulators

• Destroy the ground grid

Field experience of hand washing

Hand wash not suitable on Polymer insulators or porcelain silicone:

Granular dust/dirt/road grim particles seemed to scratch the surface with minimum force;

Hand washing push the dust against the seam (hard to clean)

Scratches on porcelain silicone insulator by hand wash

Seam of polymer insulators introduced in manufacturing process

Field Recommendations

Polymer and silicone insulators should be flood washed only.

High pressure or hand wash can be done on porcelain insulators

Washing Interval Spring and Fall

When the temperature fluctuates around the freezing mark, the roads are usually salted

Heavy spring accumulations of snow

May require frequent washing

Outages for washing and maintenance

Less critical washing deferred to fall to ensure outages for more critical washing

Substation Wash Schedule

Based on the substation criticality and pollution contamination level

Ongoing review of the washing frequency

Washing Frequency Substations

2 per year 10

1 per year 10

1 per 2 years 4

1 per 3 years 11

1 per 4 years 1

PILOT PROJECT – DOBLE IPM

Initialized in 2009 to utilize condition monitoring of pollution severity

Doble IPM installed on one substation next to highway and river

PILOT PROJECT – DOBLE IPM @ 32sub

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LOCATION OF THE CURRENT SENSOR

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CURRENT SENSTOR MOUNTING LOCATION

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IPM 6 Channels connection

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STANDALONE INSULATOR

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DOBLE IPM METHODOLOGY

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DOBLE IPM METHODOLOGY

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Evaluation of Pollution Level

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DOBLE IPM INTERFACE

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DOBLE IPM LEAKAGE CURRENT MEASUREMENT

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32S READING

DOBLE IPM LEAKAGE CURRENT MEASUREMENT

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I_peak plot

Doble IPM EXPERIENCE

CPU down for a couple of times in the first year

Lake of Doble support

Benchmark is not available (Doble benchmark?) Washing

No risk tolerance in insulator flashover

Data correlation between IPM measurement and other data source (i.e. swab)

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Conclusions

Washing committee with concentrated effort: flashover outages drops and duration decreases

Explore other means of pollution monitoring

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