contact voltage at toronto hydromydocs.epri.com/docs/...jodie_lane_conference_epri...2009 jodie lane...
TRANSCRIPT
Contact Voltageat
Toronto Hydro
Detection, Mitigation, Prevention
Presented by:
Ben La Pianta , P.Eng., MBAVice PresidentDistribution Grid Management
2009 Jodie Lane National ConferenceStray Voltage Detection, Mitigation & Prevention
Agenda
• Toronto Hydro-Electric System – Company Overview
• Contact Voltage at Toronto Hydro – A Historical Perspective
• Contact Voltage - Emergency Declaration Level III
• Technical Summary - Assessment, Diagnosis, Challenges
• Moving Forward – Our Asset Management Plan
• Summary
• Closing
• Q&A
Company Overview
Toronto Hydro service territory: • Approximately 688,000 customers
Transmission
Generation
Distribution
HydroOne
Ontario Power
Generation & Others
TorontoHydro
Local Distribution Companies (LDCs) such as Toronto Hydro manage their local infrastructure and
have the direct relationship with customers
Electricity in Ontario:Where we fit in
About Toronto Hydro-Electric System
• Largest municipal utility in Canada
• 688,000 Business and Residential Customers in the City of Toronto
• Distributes 18% of electricity in the Province of Ontario
• Summer‐peaking utility (System Peak 5000 MW)
• Designs and delivers Conservation and Demand Management programs that support a provincial call to create a “Culture of Conservation”
Toronto Hydro CorporationCorporate Structure
Board of Directors
Board of Directors
97% of revenueElectricity Distribution Conservation & Demand ManagementRenewable Generation(Green Energy Act)
3% of revenue Energy Services to the CityStreet LightingCity of Toronto Renewable Generation
Toronto Hydro-Electric System Toronto Hydro Energy Services
Board of Directors
Toronto Hydro Corporation
Strategic Focus
Customer Service Customer Service
Contact Voltage at Toronto Hydro A Historical Perspective
Historical Perspective
Prior to fatal shock incident in NYC (2004)
Frequency & impact of shocks very, very lowNo preventative maintenance to address CV Shocks were treated as isolated incidentsNot perceived to be a systemic concernStill the case in many situations and jurisdictions
Historical Perspective
Post fatal shock incident in NYC (2004)
Increase legislative burden, proof of ‘due diligence’Increase in regulatory intervention/awarenessTriggered wide scale media attentionErosion of public trustCreated industry focus on the issue of CVTriggered formation of Working Groups (IEEE, EPRI)
Genesis for the creation of “Jodie Lane Conference”
Historical Perspective
January 29/09 – Five School children shocked
January 13/09 – 2nd Dog fatally shockedNovember 20/08 – 1st Dog fatally shocked
January 30/09Declared Level III Emergency
January 29/09 – Engage Ontario Regulator
January 09 – Engaged PSC to scan for CV
2007 – Dog sustains shock from handwell2007 – Pedestrian shocked by bridge handrail
2006 & prior – no known records of CV incidents
Contact Voltage Emergency Response Level III
Mobilization
Declared highest level of emergency (Level III – Jan 30/09)
Activated Incident Command Centre(s)
Seized control of affiliate assets (street light system)
Labour Relations – clarify expectations i.e. "all hands on deck”
Suspended all ‘non-emergency’ work
Communication – Shareholder, Agencies, Customers, Ratepayers, Media
Increased scanning resources
Jan 30/31 – Begin mobilization of people, materials, equipment
Feb 1–28 – Inspected/repaired/replaced handwells/ SL poles
Emergency Response Objectives
Ensure worker and public safety (“make safe”)Fast & Visible Mobilization (within 3 days)Simple 3 step field execution process
Identify & remediate
unsafe equipment
1Define defective equipment for follow-up work
2
+ + Collect condition data and test
new standards
3
Scan entire City of TorontoManage expectations (regulator and public) Complete effort within 30 daysIndentify immediate follow-up work (define next steps)
What Was Accomplished
Handwells Inspected 11,765
Poles Inspected 39,821
# of calls reporting contact voltage 268
Individual Pieces of Material/Equipment
Purchased160,000
Number of Maps Used 1,543
People Involved >1,200
Total Hours Spent 98,401 Cost > $14 M
CV Events by Asset Owner
Customer reported events where TH or the Contractor have found no CV
Total CV events approximately 1600 (1350 from scan, 250 from inspection)
Contact Voltage Histogram
1074
198106
40 42 17 18 7 2 0 3 7 5 180
200
400
600
800
1000
1200
70% of CV were in 1-5 volt range
13% of CV were in 5.1-10 volt range
7% of CV were in 10.1-15 volt range
Full Line potential !
CV Events by Asset Owner
TPA = TTC, BIA, Traffic Lights, Bus SheltersOther = Customer owned assets
Post Level III
Contact Voltage Histogram
119
23 11 8 4 2 0 1 1 1 0 0 1 10
200
Post Level III
Summary of Technical Assessment, Diagnosis, Challenges
Common Locations of CV
Metallic plates and coversDirect contact with exposed conductor or indirectly through another
medium (i.e. salt water)
Concrete/Steel Poles Direct contact with exposed conductor
Concrete Structures (including sidewalks, bridges, etc…)
Conductive salt water saturates concrete and forms a voltage gradient
Signalized IntersectionsIntegrity of the grounding grid is suspect or insufficient
Examples of Inspection Findings
•Split-bolt tape insulation has degraded
120 volts measured
Examples of Inspection Findings
•PVC tape on split-bolt splice improperly applied
Exposed conductor
Examples of Inspection Findings
•Handwell w/ live supply was paved over
Excavated handwell with live conductors
Examples of Inspection Findings
•Damage from civil contractor
Rebar from sidewalk has penetrated the handwell walls
Examples of Inspection Findings
•Damage from civil contractor
Concrete has penetrated handwell
Common Diagnosis
Aging AssetsInsulation degradation, accelerated by harsh environment, including water, ice, salt
Degradation of cable jackets, brittle/cracked, likely due to repeated hot/cold seasonal change
Third party damageHandwells paved over, damaged, rebar penetrating, unauthorized access
Non-compliance with construction standardsSubstandard /unsuitable materials i.e., marrettsPoor workmanship i.e., taped splicesFailure to replace insulation barriers, guards, etc…
Challenges
1. CV detected on 3rd party assetsTransit & traffic polesPrivate infrastructure (advertisements, street furniture, lighting)Other infrastructure (Other Utilities, control cabinets, conduit, etc…)
Need a process for communication/resolutionRegulatory compliance
Cost recovery/allocationAre Service Level Agreements (SLA’s) required?Legislatively, who is responsible?
2. 3rd party accessControl access (via process, design, etc…)Physical barriers (proprietary locking mechanism, special bolts, etc…)Engagement & communication of process, practices, public safety
Challenges . . . cont’d
3. Safety by designHow do you ensure the design is as safe as is reasonably possible?Are you using the correct equipment/materials for the job?Circuit Protection - need to revisit legacy standards?
4. Installation practicesHow do you ensure installations are as per standard?How do you efficiently execute QA/QC?What are acceptable tolerances, margin for error?
5. Data & RecordsDo you know where all your infrastructure is located?Data collection/storage costs $$$. GIS vs. paper vs. electronic?Harmonization of records (Legacy systems, standards, records)
Moving Forward
Our Asset Management Plan
Asset Investment Plan
Level III Emergency Follow Up
Plans to complete follow up actions from Level III emergency contact voltage inspection are in place
Where permanent fixes were not possible during the Level III emergency, our 2010 EDR filing proposes to:
Replace handwell lids with non conductive lidsPrevent unauthorized accessRepair deteriorated wiring in handwells/hand-holesReplace poles that are no longer feasible to repairRevisit “no access possible” locations to verify presence of
unauthorized access/contact voltage
Asset Transition, Maintenance,Data Collection
Acquire street light assets via regulatory processIntegrate SL assets into LDC GIS registryConduct asset condition assessmentInclude asset investment plan into next OEB rate application
Develop appropriate maintenance programsVisual inspectionManual detection (readily available technologies, inexpensive, efficient?) Mobile scanning- Proprietary technology – limited vendors, efficient, effective, comprehensive, fast- Considerably more expensive relative to manual testing, needs regulatory approval
Data collectionUtilize hand-held PDA’s (robust data, pictures, GPS location, etc…)Reduce response time to serious hazards
Hazard Mitigation Strategies
Leverage existing THESL asset condition tools (i.e. Asset Condition Assessment / Health Index Calculator) to prioritize work from highest potential hazard to lowest. Possible recommendations may include:
Replacement of entire handwell with composite materialSpec higher quality electrical wireIncrease electrical insulation of the pole structureExplore new connector technologiesImprove electric circuit protection (i.e., fusing, isolation transformers)
Other technologies i.e. non-conductive lids, insulating paint
Specifically…
•THESL has included in our 2010 EDR filing:
Replacing 1,000 “high risk”handwells with non-conductive ones
Replacement of 8,000 handwell covers with non-conductive covers
Grounding 2,000 handwell frames where replacement is not possible
Summary
• Complete remedial work in 2009 arising from the Level III emergency
• Implement permanent CV Scanning & support processes and systems
• Work with OEB on cost recovery (Level III emergency) & go-forward costing
• Seek regulatory approval to acquire street lighting assets
• Develop short-term 2009/10 street light investment plan
• Develop long-term investment plan (standards, capital, O&M)
• Continue to work collaboratively with agencies, boards, commissions, and private sector to resolve issues (i.e. Electrical Safety Association, City Traffic, Business Improvement Associations, Contractors, other Utilities, etc…
• Enhance community outreach (education, media, etc…)
In Closing . . .
We at Toronto Hydro are dedicated to ensuring our assets do not pose safety risks to the public or employee
We are working together with regulators and safety authority to mitigate any outstanding issues arising from Level III emergency
We are prudently increasing our investment and actively improving our own standards and processes to mitigate sources of contact voltage