Contact Voltage at Toronto Hydro

Transcription

1 Contact Voltage at Toronto Hydro Detection, Mitigation, Prevention Presented by: Ben La Pianta, P.Eng., MBA Vice President Distribution Grid Management 2009 Jodie Lane National Conference Stray Voltage Detection, Mitigation & Prevention

2 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

3 Company Overview

4 Electricity in Ontario: Where we fit in Generation Transmission Ontario Power Generation & Others Hydro One Distribution Local Distribution Companies (LDCs) such as Toronto Hydro manage their local infrastructure and have the direct relationship with customers Toronto Hydro service territory: Approximately 688,000 customers Toronto Hydro

5 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

6 Toronto Hydro Corporation Corporate Structure Board of Directors Toronto Hydro Corporation Board of Directors Board of Directors Toronto Hydro-Electric System Toronto Hydro Energy Services 97% of revenue Electricity Distribution Conservation & Demand Management Renewable Generation (Green Energy Act) 3% of revenue Energy Services to the City Street Lighting City of Toronto Renewable Generation

7 Customer Service Strategic Focus

8 Contact Voltage at Toronto Hydro A Historical Perspective

9 Historical Perspective Prior to fatal shock incident in NYC (2004) Frequency & impact of shocks very, very low No preventative maintenance to address CV Shocks were treated as isolated incidents Not perceived to be a systemic concern Still the case in many situations and jurisdictions

10 Historical Perspective Post fatal shock incident in NYC (2004) Increase legislative burden, proof of due diligence Increase in regulatory intervention/awareness Triggered wide scale media attention Erosion of public trust Created industry focus on the issue of CV Triggered formation of Working Groups (IEEE, EPRI) Genesis for the creation of Jodie Lane Conference

11 Historical Perspective 2006 & prior no known records of CV incidents 2007 Pedestrian shocked by bridge handrail 2007 Dog sustains shock from handwell November 20/08 1 st Dog fatally shocked January 13/09 2 nd Dog fatally shocked January 09 Engaged PSC to scan for CV January 29/09 Five School children shocked January 29/09 Engage Ontario Regulator January 30/09 Declared Level III Emergency

12 Contact Voltage Emergency Response Level III

13 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

14 Emergency Response Objectives Ensure worker and public safety ( make safe ) Fast & Visible Mobilization (within 3 days) Simple 3 step field execution process 1 Identify & remediate unsafe equipment 2 Define defective equipment for follow-up work Collect condition data and test new standards Scan entire City of Toronto Manage expectations (regulator and public) Complete effort within 30 days Indentify immediate follow-up work (define next steps)

15 What Was Accomplished Handwells Inspected 11,765 Poles Inspected 39,821 # of calls reporting contact voltage Individual Pieces of Material/Equipment Purchased ,000 Number of Maps Used 1,543 People Involved >1,200 Total Hours Spent 98,401 Cost > $14 M

16 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)

17 Contact Voltage Histogram Full Line potential! 70% of CV were in 1-5 volt range 13% of CV were in volt range 7% of CV were in volt range

18 CV Events by Asset Owner Post Level III TPA = TTC, BIA, Traffic Lights, Bus Shelters Other = Customer owned assets

19 Contact Voltage Histogram Post Level III

20 Summary of Technical Assessment, Diagnosis, Challenges

21 Common Locations of CV Metallic plates and covers Direct 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 Intersections Integrity of the grounding grid is suspect or insufficient

22 Examples of Inspection Findings 120 volts measure d Split-bolt tape insulation has degraded

23 Examples of Inspection Findings Exposed conductor PVC tape on split-bolt splice improperly applied

24 Examples of Inspection Findings Excavated handwell with live conductors Handwell w/ live supply was paved over

25 Examples of Inspection Findings Rebar from sidewalk has penetrated the handwell walls Damage from civil contractor

26 Examples of Inspection Findings Concrete has penetrated handwell Damage from civil contractor

27 Common Diagnosis Aging Assets Insulation 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 damage Handwells paved over, damaged, rebar penetrating, unauthorized access Non-compliance with construction standards Substandard /unsuitable materials i.e., marretts Poor workmanship i.e., taped splices Failure to replace insulation barriers, guards, etc

28 Challenges 1. CV detected on 3 rd party assets Transit & traffic poles Private infrastructure (advertisements, street furniture, lighting) Other infrastructure (Other Utilities, control cabinets, conduit, etc ) Need a process for communication/resolution Regulatory compliance Cost recovery/allocation Are Service Level Agreements (SLA s) required? Legislatively, who is responsible? 2. 3 rd party access Control access (via process, design, etc ) Physical barriers (proprietary locking mechanism, special bolts, etc ) Engagement & communication of process, practices, public safety

29 3. Safety by design Challenges... cont d How 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 practices How do you ensure installations are as per standard? How do you efficiently execute QA/QC? What are acceptable tolerances, margin for error? 5. Data & Records Do you know where all your infrastructure is located? Data collection/storage costs $$$. GIS vs. paper vs. electronic? Harmonization of records (Legacy systems, standards, records)

30 Moving Forward Our Asset Management Plan

31 Asset Investment Plan

32 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 lids Prevent unauthorized access Repair deteriorated wiring in handwells/hand-holes Replace poles that are no longer feasible to repair Revisit no access possible locations to verify presence of unauthorized access/contact voltage

33 Asset Transition, Maintenance, Data Collection Acquire street light assets via regulatory process Integrate SL assets into LDC GIS registry Conduct asset condition assessment Include asset investment plan into next OEB rate application Develop appropriate maintenance programs Visual inspection Manual 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 collection Utilize hand-held PDA s (robust data, pictures, GPS location, etc ) Reduce response time to serious hazards

34 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 material Spec higher quality electrical wire Increase electrical insulation of the pole structure Explore new connector technologies Improve electric circuit protection (i.e., fusing, isolation transformers) Other technologies i.e. non-conductive lids, insulating paint

35 Specifically THESL has included in our 2010 EDR filing: Replacing 1,000 high risk handwells with nonconductive ones Replacement of 8,000 handwell covers with nonconductive covers Grounding 2,000 handwell frames where replacement is not possible

36 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 )

37 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