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September 29, 2008

Report released on downtown Vancouver power outage

VANCOUVER – BC Hydro has filed its report on the July downtown Vancouver power outage with the British Columbia Utilities Commission. The report includes the findings and recommendations from BC Hydro’s investigation of the incident, as well as the opinions and recommendations of an independent panel of industry experts.

The report concludes the root cause of the outage was an overheated connector in a manhole located in the five-hundred block of Richards Street. The overheated connector caused a chain reaction fire and explosion that led to the failure of 13 other circuits in the manhole, resulting in a power outage to approximately 2,000 customers.

While underground circuit failures are not uncommon, the report finds the downtown Vancouver outage was unique because of the fire leading to the failure of other circuits, and the fact the connector was only three years old when these components usually have a lifespan of 30 or more years.

The panel of independent industry experts reviewed BC Hydro’s investigation of the incident, and provided a number of conclusions and recommendations. The panelists include Richard Brown, vice-president of operations for Quanta Technology and the author of the book, Electric Power Distribution Reliability; John Densley, a researcher formerly with Ontario Hydro and now a leading consultant on electrical insulation systems, and Ken Hamilton, an underground standards design engineer for Manitoba Hydro with expertise in the design and construction of underground distribution systems and national standards.

As a result of the report and the independent panel’s recommendations, BC Hydro is implementing a number of changes aimed at mitigating outages caused by underground circuit failures, including:

  • Creating a BC Hydro fire marshal position and improving protocols and training with the Vancouver Fire Department;
  • Undertaking a program to identify, inspect and test connectors similar to the connector that failed;
  • Evaluating the use of additional fire retardant barriers;
  • Modifying manhole entry procedures to include recording infrared temperatures readings in a database;
  • Investigating the downtown underground infrastructure to determine methods of improving critical infrastructure in the downtown core.

BC Hydro is also in the process of evaluating and revising the Detailed Condition Assessments program to further enhance its effectiveness. The program uses leading diagnostic techniques to assess circuits, and prioritizes assessments based on factors such as the circuit’s importance, condition, number of faults, age and expert opinion. The program was initiated by BC Hydro in 2004, and since that time, there has been an annual average of approximately 20 underground circuit failures – a decrease of 50 per cent.

The downtown Vancouver outage occurred on July 14 at 8:54 a.m. As outlined in the report, BC Hydro crews removed and replaced nearly four kilometres of underground cable to restore power. Power was restored to approximately half of customers within 24 hours, and to approximately 90 percent within 48 hours. Power was restored to the final customer at approximately 6 p.m. on July 17.

The BC Hydro report on the downtown Vancouver outage and related documents are now available online at the following links:

BC Hydro report [PDF, 278 Kb]
Appendix: Independent panel review final report [PDF, 298 Kb]
Appendix: Cable Ampacity Program Study: Manhole 2445 [PDF, 37 Kb]
Appendix: Various Utilities Liability/Exemption Clauses [PDF, 55 Kb]
Appendix: BC Hydro, British Columbia Utilities Commission interim report [PDF, 396 Kb]


Dag Sharman
BC Hydro Media Relations
Phone: 604 623 4022

Source: BC Hydro

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