Widespread Electric Power Failures
in Nova Scotia

Storm of 27-28 November 1997







Cover



REPORT NSUARB-P-401.20

Nova Scotia Utility and Review Board


In the Matter of the Public Utilities Act

-and-

IN THE MATTER OF AN INVESTIGATION
by the
NOVA SCOTIA UTILITY AND REVIEW BOARD
under Section 18 and Section 19 of the Public Utilities Act
into the manner in which
NOVA SCOTIA POWER INC.
provided service to its customers during
Power Outages occurring on its System
during the months of November and December 1997.


Report
Dated: February 9, 1998



Table of Contents


       
Summary i
  Introduction i
  Methodology ii
  Conclusions ii
  Findings and Directives ii
    1.  Weather Conditions ii
    2.  Adequacy of the Number of Personnel iii
    3.  Difficulty in Reaching Trouble Spots iv
    4.  Adequacy of Routine Maintenance of Distribution Lines iv
    5.  Protection Coordination and System Design v
    6.  Communications vi
    7.  Distribution System Reliability vi
    8.  Summary of Required Filings vii
 
1.0 Introduction 1
  1.1  Methodology 2
  1.2  Glossary 2
  1.3  Frequency and Duration of Power Outages 4
    1.3.1  Utility Actions During Power Outage 4
    1.3.2  Factors Influencing Frequency of Outages 4
    1.3.3  Factors Influencing Duration of Outages 4
 
2.0 Events of November 27 and November 28, 1997 5
  2.1  Overview of Storm Severity 5
  2.2  Customers Affected by Region 5
  2.3  Regional Events 6
 
3.0 Reasons for the Power Outages 8
 
4.0 Weather 8
  4.1  Data Sources 8
  4.2  Weather Severity 9
  4.3  Finding 10
 
5.0 Adequacy of the Number of Personnel 11
  5.1  Total Employees 11
  5.2  Total NSPI Lineworkers 12
  5.3  General Comments Regarding Adequacy of Number of Personnel 13
  5.4  Findings 14
 
6.0 Difficulty in Reaching Trouble Spots 14
  6.1  Location 14
    6.1.1  Distance of Dispatch Locations from Problem Areas 14
    6.1.2  Transportation Difficulties 14
    6.1.3  Communications 15
  6.2  Accessibility 15
  6.3  Findings 15
 
7.0 Adequacy of Routine Maintenance of Distribution Lines 16
  7.1  NSPI Maintenance Practices 16
  7.2  Findings 16
 
8.0 System Design and Protection Considerations 17
  8.1  Data Sources 17
  8.2  Background 17
  8.3  Protection Considerations 17
  8.4  Findings 18
 
9.0 NSPI Reliability Statistics 19
  9.1  Comparison with Other Utilities (1996 levels except as noted) 19
  9.2  NSPI Total System Reliability Levels (1990-1996) 19
  9.3  NSPI Reliability Levels by Region (1990 and 1996) 20
  9.4  Individual Feeder Reliability Levels (1990-1996) 20
  9.5  Findings 21
 
10.0 Customer Communication With NSPI During Emergency 22
  10.1  NSPI Call Centre 22
  10.2  Distribution Control Centre at Ragged Lake 23
  10.3  Findings 23
 
Appendices
Appendix 1:  NSPI T&D Field Service Organization 1997
            [T&D: Transmission and Distribution]



Page i



Nova Scotia Utility and Review Board
Power System Outages in Nova Scotia
Summary

Introduction

Nova Scotia was struck by a winter storm on Thursday, November 27, 1997 which continued to affect the region through the 28th.  A second storm hit the region on Tuesday, December 2, 1997.  This report focuses primarily on the former storm, which produced extended outages in the Nova Scotia Power Inc. (NSPI) system.

Approximately 35,000 customers were without power for six hours or longer.  A total of 11,000 customers had outages of between 12 and 24 hours.  Customers affected for over 24 hours totalled some 3,100.  The longest outage of 73 hours affected 120 customers in McCallum Settlement in the Truro Region.  During the storm a total of 59 poles fell and had to be replaced.  These included 32 in the Western Region,12 in the Stellarton Region, six in the Sydney Region, seven in the Truro Region and two in the Sackville Region.

Numerous complaints have been voiced by electricity users in the affected areas through letters to both the Board and the media.  Political leaders have expressed concern with the frequency and duration of the outages that have occurred in various regions of Nova Scotia both during this recent storm and also over the past few years.

The Nova Scotia Utility and Review Board (NSUARB) directed its staff to carry out an independent review of the outages.  Its findings in connection therewith are set out below.

The Board is authorized to conduct this investigation by the Public Utilities Act and in particular sections 18 and 19:


Supervision of utility by Board
section 18 The Board shall have the general supervision of all public utilities, and may make all necessary examinations and inquiries and keep itself informed as to the compliance by the said public utilities with the provisions of law and shall have the right to obtain from any public utility all information necessary to enable the Board to fulfil its duties.

Summary investigation by Board
section 19 Whenever the Board believes that any rate or charge is unreasonable or unjustly discriminatory, or that any reasonable service is not supplied, or that an investigation of any matter relating to any public utility should for any reason be made, it may, on its own motion, summarily investigate the same with or without notice.




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Methodology
In order to identify the factors contributing to the severity of power outages that occurred as a result of the storm on November 27 and 28, 1997, numerous information requests were prepared and sent to NSPI.  NSPI's responses to these information requests were reviewed and field inspections were conducted by Board staff in the Stellarton and Sydney Regions of the province which were subject to long or frequent interruptions of power.  In addition, interviews were conducted with leaders of the International Brotherhood of Electrical Workers, engineers and other professionals with the Maine Public Service Commission, New Brunswick Power and Canadian Electrical Association.  As well, numerous letters and media articles were reviewed.

Conclusions
There are several reasons for the number and duration of the outages that occurred in Nova Scotia during the period November 27 and 28, 1997.  In the opinion of the Board the following factors provided the most significant contribution to these outages:

a) weather conditions;
b) adequacy of the number of personnel;
c) difficulty in reaching trouble spots;
d) adequacy of routine maintenance of distribution lines;
e) protection coordination and system design.


Findings and Directives
The Board summarizes its findings and issues the following directives to Nova Scotia Power Inc.:

l. Weather Conditions
The Board finds that the weather was not unduly severe based on extremes of temperature, wind or precipitation.  However, widespread icing conditions resulted in power line damage.  The type of damage that was observed by Board Staff and described by NSPI is consistent with the following weather effects:

a) electrical wires when coated with ice will sag under the weight of the ice;
b) sagging wires in some instances will come into contact with other wires, trees or the ground;



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c) electrical wires coated with ice are heavy and will exert a powerful force on the insulators, crossarms and poles themselves.  In some instances this force will be sufficient to bring down the poles;
d) the wind that accompanies the freezing rain may cause electric wires to be blown about and occasionally to come into contact with each other;
e) trees will become coated with ice, the weight of which may cause branches to be broken or trees to fall.  In some instances these branches or trees may be blown onto the power lines causing faults, or in extreme conditions bringing down the lines;
f) icing conditions and blowing snow will affect the road conditions and consequently will increase the response times of emergency repair crews.


2. Adequacy of the Number of Personnel

The question of the availability of lineworkers has been carefully considered by the Board.  It is difficult to be certain as to the optimum number of lineworkers that a utility should have available for transmission and distribution routine and emergency line work.  The Board is of the opinion that downsizing contributed to the severity of the outages investigated in this study, but that was by no means the only cause.  The Board recognizes that the downsizing by NSPI is consistent with that undertaken by many utilities and indeed is less drastic than the downsizing undertaken by some utilities.

NSPI is directed to investigate, report on costs and recommend to the Board by December 30, 1998 a proposed course of action for each of its six districts, which is to include the following:

a) a power management program designed to utilize the latest innovations in distribution automation technology for the worst performing feeders in each Region; and
b) restoring the number of lineworkers to 1994 levels at a minimum; or
c) some combination of a) and b).


The above directive should not be interpreted as being critical of the efforts of those lineworkers and others involved in restoring the power.  Interviews and field visits by Board staff support the Board's appreciation of the hard work, dedication and professionalism of NSPI's field staff.  The Board also recognizes that NSPI is currently proposing to implement a technology based Power Outage Management Program and the Board will consider this program in the context of item 2 (a) above.

NSPI is directed to provide the Board with a proposed reporting format by December 30, 1998 for an annual report to be filed first in the Spring of 1999 summarizing the actual distribution line crew sizes for each of its six regions, as well as an analysis of actual


Page iv



distribution capital expenditures, and operating and maintenance expenditures for both the past year and estimated levels for the future year.

3. Difficulty in Reaching Trouble Spots

Portions of some distribution lines are located in forested areas away from highways.  Increased time is required to put lines back in service when stormy weather makes accessibility difficult.  NSPI is directed to continue and accelerate the program currently underway to move these lines out to roadsides where practical and, where not practical, to ensure that the utilization of technology-based applications such as the currently-used Sentry devices is maximized.  The Sentry is a remote sensing device that is useful in locating faults by identifying homes or lines that are without power.

Consistent with these actions, NSPI is directed to file with the Board by July 31, 1998 the estimated costs and work plan for this program in all districts for the next two years.

As was observed by Board staff during its inspection of lines in the Stellarton Region, NSPI's right-of way tree trimming program has been very successful.  The Board considers it imperative that this program be continued throughout the province in the same aggressive manner and accelerated where appropriate.  In addition, a proactive approach must be adopted for the resolution of problems caused by clear cutting and the resulting erosion of tree roots near distribution feeders.  This erosion of tree roots can lessen the ability of a tree to withstand high winds, thus increasing the possibility of its falling on a power line.

NSPI is directed to develop and file with the Board by July 31, 1998 a proposed format for future annual reports to the Board which are to provide details of ongoing expenditures on right-of way tree trimming in each of the six regions, as well as documenting steps taken to resolve the problem of erosion of tree roots near distribution feeders such as public education programs and the purchasing of additional right-of way land in vulnerable areas.

4. Adequacy of Routine Maintenance of Distribution Lines

The Board is of the opinion that the adequacy of the routine inspection of poles, conductors, anchors, cross arms, and insulators will strongly influence the success of the utility's efforts to reduce the number of power outages.

NSPI is directed to research the methods for routine inspection and maintenance being used by North American electric utilities as related to overhead distribution system components and report back to the Board with the results of this research and any recommendations not later than July 31, 1998.


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Considerations should include but not be limited to:

a) basing the frequency of line and apparatus inspections and maintenance upon age or according to the inspector's last report, rather than the present practice of inspecting and performing maintenance on a periodic basis regardless of condition;
b) the use of a composite percentage condition for pole locations based on observed condition of the various components, which could then be used to determine or f1ag impending repairs or retirements as opposed to a fixed life assumption;
c) the utilization of a preventive maintenance approach that incorporates the lines' environment into the inspection criteria.


5. Protection Coordination and System Design

To reduce the severity of outages on certain feeders, it is recommended that consideration be given to strengthening these feeders through appropriate overbuilding measures such as multiple guy wires, utilization of larger pole sizes and insulating for higher voltage levels.  For the thirty worst performing feeders in Nova Scotia, NSPI is directed to develop and file by July 31, 1998 individual feeder cost estimates for the overbuilding and strengthening of these feeders.

As an alternative to overbuilding, the number of customers affected by a feeder outage can be reduced through improved coordination of protective devices and the utilization of electronic or hydraulic reclosers, as well as backfeeding where possible.  NSPI is directed to file with the Board by July 31, 1998 a protection study and cost estimate for the thirty worst performing feeders.  This study should address the existing protection on the feeders including actual number of reclosers versus optimum number, and include estimates of the number of customers affected by a fault located near the end of the line, and by a fault located near the middle of the line.  The study is to provide recommendations regarding an increase in the number of protective devices as well as backfeeding possibilities.

The Board is concerned about the increased potential for power outages during abnormal weather conditions caused by distribution line construction which does not conform to NSPI's standards.  These distribution lines were acquired from other electric utilities in the past.

NSPI is directed to file a plan with the Board by July 31, 1998, including the associated costs of accelerating the existing NSPI program to replace all nonstandard distribution line configurations below 25 kV as quickly as possible, subject to line crew availability.


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6. Communications

During power outages in stormy weather it is vital that power line access roads be kept clear of snow and ice.  In addition, the work being carried out exposes lineworkers and others to the dangers of fallen power lines.  The Board stresses the importance of good communications between NSPI and various organizations in emergency situations.

The Board recognizes that significant changes are presently being implemented in the area of customer communications, in particular, the implementation of the Management Information System, the Interactive Voice Response System and the Power Outage Management System.  However, the Board is concerned about the capability of the Distribution Control Centre to adequately coordinate the many tasks that must be handled during a widespread series of outages such as occurred November 27 and 28, 1997.

NSPI is directed to develop and file with the Board by December 30, 1998 a power outage logistics study.  This study is to include an emergency plan describing the coordination of NSPI activities with the Emergency Measures Organization, as well as other emergency services organizations, telephone and cable TV personnel, Department of Transportation and Public Works and municipal public works departments throughout the province.  The Board understands that NSPI has received a request from the Nova Scotia Department of the Environment to carry out a related study.  NSPI is directed to utilize part or all of that study in carrying out this directive.  In addition, this study is to address the coordinated activities of the Call Centre and the Distribution Control Centre, the role played by the Management Information System, the Interactive Voice Response System and the Power Outage Management System.  This report would include, but not necessarily be limited to, the initial assessment of outage situations, the logistics of moving lineworkers from one area to another, allowing for sleep time and feeding of the work crews, moving equipment such as mobile transformers, arranging for snow removal and the towing of abandoned cars.

7. Distribution System Reliability

The Board recognizes that there is a trade-off between cost and reliability.  The trade-off involves finding the optimum level of technical and human resources to provide an acceptable level of reliability.

The Board directs NSPI to prepare and file by December 30, 1998 a distribution system reliability study that will focus on the determination of target reliability levels by region that addresses both the number and the duration of outages.  The study is to utilize benchmark data from other similar-sized North American utilities as well as trade associations.  In addition, NSPI is directed to develop and file with the Board in the same report a proposed


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format for reporting annual frequency and duration of outages for the utility as a whole, as well as by region and by feeder, for the worst performing feeders in each region.

8. Summary of Required Filings

The following table summarizes the various filings that have been ordered by the Board in the preceding findings and directives:

Description Due Date
Line Accessibility Work Plan July 31, 1998
Annual Report Format:
Tree Trimming & Erosion Problem Correction
July 31, 1998
Benchmark Research:
Routine Inspection & Maintenance
July 31, 1998
Cost Estimates for Replacement of
Nonstandard Line Configurations
July 31, 1998
Cost Estimates for Feeder Overbuilding July 31, 1998
Protection & Backfeeding Alternatives July 31, 1998
Technology vs Staffing Study Dec. 30, 1998
Proposed Annual Reporting Format
on Distribution Staffing and Expenditures
Dec. 30, 1998
Power Outage Logistics Study Dec. 30, 1998
Distribution System Reliability Study
and Outage Report
Dec. 30, 1998




Power System Outages in Nova Scotia




Page 1



1.0 Introduction

Nova Scotia was struck by a winter storm on Thursday, November 27, 1997 which continued to affect the region through the 28th.  A second storm hit the region on Tuesday, December 2, 1997.  This report focuses primarily on the former storm, which produced extended outages in the Nova Scotia Power Inc. (NSPI) system.

Approximately 35,000 customers were without power for six hours or longer.  A total of 11,000 customers had outages of between 12 and 24 hours.  Customers affected for over 24 hours totalled some 3,100.  The longest outage of 73 hours affected 120 customers in McCallum Settlement in the Truro Region.  During the storm a total of 59 poles fell and had to be replaced.  These included 32 in the Western Region,12 in the Stellarton Region, six in the Sydney Region, seven in the Truro Region and two in the Sackville Region.

Numerous complaints have been voiced by electricity users in the affected areas through letters to both the Board and the media.  Political leaders have expressed concern with the frequency and duration of the outages that have occurred in various regions of Nova Scotia both during this recent storm and also over the past few years.

The Nova Scotia Utility and Review Board (NSUARB) has directed its staff to carry out an independent review of the outages.  Its findings in connection therewith are set out below.

The Board is authorized to conduct this investigation by the Public Utilities Act and in particular sections 18 and 19:

Supervision of utility by Board
section 18 The Board shall have the general supervision of all public utilities, and may make all necessary examinations and inquiries and keep itself informed as to the compliance by the said public utilities with the provisions of law and shall have the right to obtain from any public utility all information necessary to enable the Board to fulfil its duties.
Summary investigation by Board
section 19 Whenever the Board believes that any rate or charge is unreasonable or unjustly discriminatory, or that any reasonable service is not supplied, or that an investigation of any matter relating to any public utility should for any reason be made, it may, on its own motion, summarily investigate the same with or without notice.




Pages 2, 3 & 4



1.1 Methodology

In order to identify the factors contributing to the severity of power outages that occurred as a result of the storm on November 27 and 28, 1997, numerous information requests were prepared and sent to NSPI.  NSPI's responses to these information requests were reviewed and field inspections were conducted by Board staff in Stellarton and Sydney Regions of the province which were subject to long or frequent interruptions of power.  In addition interviews were conducted with leaders of the International Brotherhood of Electrical Workers, engineers and other professionals with the Maine Public Service Commission, New Brunswick Power and Canadian Electrical Association.  As well, numerous letters and media articles were reviewed.

1.2 Glossary

The following are electric utility terms that are used throughout this report:
Transmission System Portion of the electric utility plant used for the purpose of transmitting electric energy in bulk to other principal parts of the system or to other utility systems.
Transmission Line One or more circuits of the transmission system generally operating at a high voltage.  NSPI operates transmission lines at voltages of 69,000 V or greater.
Distribution System Portion of the electric utility plant used for the purpose of delivering electric energy from convenient points on the transmission system to consumers.
Distribution Feeder
or Distribution Line
One or more circuits of a distribution system either direct-buried, in conduits, or on the same line of poles or supporting structures, operating at a relatively low voltage compared to transmission.  NSPI operates distribution feeders at 4,000 V, 12,000 V and 25,000 V.
Outage (Fault) Disruption of electric service which can be either planned or unplanned.  The latter occurs when a current flows from one wire to ground or to another wire owing to an abnormal connection (including an arc) such as a tree limb or a fallen line.  Very high currents can travel from a wire to ground or to another wire.  These high currents can damage the electrical system if allowed to continue.  As such, protective devices such as fuses, reclosers and circuit breakers are utilized in order to protect the utility's wires and apparatus and to isolate the part of the distribution line that has a problem, thus allowing service to continue on the remaining portion of the line.
Circuit Breaker A circuit breaker is used to stop the flow of electrical current in a wire or device if the current is too great.  A circuit breaker acts like an automatic switch that can shut the power off when it senses too much current.  Once a circuit breaker opens it must be reset before power can be restored.
Recloser Reclosers are similar to circuit breakers in that they are used to stop the flow of electrical current in a wire or device if the current exceeds a preset level.  However reclosers are capable of automatically resetting or "reclosing" if the excessive current ceases.  These devices are important in restoring power after a momentary fault such as when a tree limb brushes against a power line or when animals or birds come into contact with energized electrical equipment.
Fuse A fuse is a device used to protect electrical equipment if the flow of electrical current exceeds a preset level.  Fuses are made with metals which are designed to melt when the current is high enough.  When the metal melts (or the fuse "blows") the current is interrupted.  Fuses are inexpensive but must be replaced once they have blown.
SAIDI System Average Interruption Duration Index.  This index is defined as the system average interruption duration for customers served per year.  Utilities attempt to lower this index as much as possible.
SAIDI = (Total Customer-Hours of Interruptions) ÷ (Total Customers Served)
SAIFI System Average Interruption Frequency Index.  This index is defined as the average number of interruptions per customer served per year.
SAIFI = ( Total Customer-Interruptions) ÷ (Total Customers Served)
Utilities attempt to lower this index as much as possible.
CAIDI Customer Average Interruption Duration Index.  This index is defined as the customer average interruption duration for customers interrupted during a year.
CAIDI = (Total Customer-Hours of Interruptions) ÷ (Total Customer Interruptions)
Utilities attempt to lower this index as much as possible.

1.3 Frequency and Duration of Power Outages

1.3.1 Utility Actions During Power Outage

Before examining the factors that influence the frequency and duration of power outages, it would be useful to review the activities that a utility undertakes during a power outage.  These actions lead to the identification and correction of an outage and include the following:

a) receive notification of a problem by telephone or remote sensing device;
b) locate the problem;
c) confirm whether or not a problem exists on the electric utility system (as opposed to communications wires or cable TV wires being down);
d) dispatch repair crew;
e) repair the problem.


1.3.2 Factors Influencing Frequency of Outages

There are a number of possible reasons for the frequency of power outages that occur on any electrical system.  A partial list includes the following:

a) adverse weather conditions (lightning, freezing rain, snow, wind, etc.);
b) inadequate routine maintenance of distribution lines (equipment problems);
c) non-optimum protection coordination or system design;
d) tree contacts;
e) adverse environment (salt contamination, industrial pollution, etc.);
f) foreign interference (birds, animals, vehicles, etc.);
g) human element (human error, incorrect construction, etc.).


1.3.3 Factors Influencing Duration of Outages

There are a number of factors that can extend the outage duration time on a power system. Some of these factors include:


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a) adequacy of the number of emergency personnel;
b) capability of emergency personnel (technical competence, location familiarity);
c) difficulty in locating the trouble spot (darkness, stormy conditions, unplowed or icy roads);
d) difficulty in reaching trouble spot (access);
e) internal and external communications (ability to handle trouble calls);
f) coordination of required repair work.


2.0 Events of November 27 and 28, 1997

2.1 Overview of Storm Severity

NSPI provided both outage statistics as well as descriptions of the events that unfolded in each of its regions during Thursday, November 27 and Friday, November 28, 1997.  This information is summarized in the following sections.

The series of outages on November 27, 1997 affected numerous customers of NSPI throughout all regions of the province.  Approximately 35,000 customers were without power for six hours or longer.  A total of 11,000 customers had outages of between 12 and 24 hours.  Customers affected for over 24 hours totalled some 3,100.  The longest outage of 73 hours affected 120 customers in McCallum Settlement in the Truro Region.

2.2 Customers Affected by Region

The number of customers having outages exceeding six hours by region was as follows:


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The number of customers, by region,
having outages exceeding six hours

Thu.
Nov. 27
1997
Fri.
Nov. 28
1997
Sat.
Nov. 29
1997
Western Region 730 0 0
Halifax Region 701 0 0
Sackville Region 216 100 0
Truro Region 7,496 212 263
Stellarton Region 5,630 616 0
Sydney Region 19,976 13,030 618
Total 34,749 13,958 881

2.3 Regional Events

Western Region

Snow and 90 km/h winds began in Yarmouth in mid-afternoon on November 27, 1997.  The storm tracked through Digby and Windsor.  Major feeders were out of service in the Annapolis Valley by 5:00 p.m.  Road conditions necessitated a request for assistance from the Department of Transportation and Public Works (DOT).  All 17 line crews in the Yarmouth to Windsor area were dispatched and relieved on Friday by crews from the South Shore.  Primary causes of outages were said by NSPI to be tree limbs on power lines, trees blown down and 32 poles had to be replaced.


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Truro Region

Expecting "routine" storm conditions, most of the NSPI staff left for home at 4:00 p.m.  Thursday, November 27, 1997.  One standby crew remained.  Reports of outages from the Amherst area were received around 5:00 p.m. and a second standby crew was recalled.  By 5:30 p.m. all crews had been called.  By 7:00 p.m. the impact of the storm was realized and additional crews were requested from Halifax and Sackville.  In addition, preparations were carried out to obtain contract crews.  Road conditions were poor and necessitated a request for assistance from DOT in order to reach areas outside of Truro.  On Friday, all but two crews on sleep time were dispatched along with three contract crews and two Halifax crews.  An additional crew was formed by a labour pool member and two lineworkers from other work areas.  Plans were made to deploy four crews from the Western Region on Saturday.

Stellarton Region

Wet snow and heavy wind began around 4:00 p.m. on Thursday, November 27 and the first outages were reported at 5:30 p.m.  By 7:30 p.m.  roads were icy and one crew vehicle went off the road.  A tow truck took 2 hours to reach this vehicle.  At 8:00 p.m. a feeder from the Bridge Avenue substation went out of service affecting 3,000 customers between Stellarton and Trenton.  At 10:00 p.m. a 69,000 volt transmission line out of Trenton went out of service, resulting in a loss of power to Trenton, New Glasgow, Westville and Stellarton.  Between 4:00 a.m. and 10:00 a.m. on Friday, November 28, 1997 telephone and cellular systems were lost in the Stellarton area, eliminating NSPI's ability to communicate with its customers, police and fire services.  Until the major feeders were restored at 9:00 a.m. Friday, the full extent of the outages on the distribution system was unknown to NSPI since the distribution system is fed from the major feeders.  Crews assembled on Thursday night included maintenance staff, mechanics, and customer service field representatives, term line staff, office staff, former employees, and contractors.  On Friday, calls for assistance were placed to the Metro Region and three crews were brought in from the Western Region.  Key problems were icing of the conductors, and trees coming into contact with lines and falling on lines and poles.  Twelve poles had to be replaced.

The Pictou Landing feeder had the longest outage at 23 hours and 33 minutes.  This feeder is relatively short at 40 km and is operated at 25 kV.  The line is 8 km from the work depot.  Two hundred and eighty-three customers were affected.

Halifax Region

The storm moved through the Metro area during the early evening of Thursday, November 27.  Three feeders went out of service, affecting 15,000 customers for three hours.  A blown fuse in an underground substation resulted in a 13-hour interruption to a 450-unit apartment


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complex in Spryfield.  A water system in Herring Cove was off for 17 hours, affecting 75 homes because of a power failure.  NSPI was not informed of this power failure until 8:00 a.m. on Friday.  At 4:00 p.m. Friday one crew was able to be dispatched to Stellarton and two crews to the Sydney Region.  Key problems included tree contacts, lines slapping together and icy roads.

Sackville Region

The storm began to affect the Sackville area around 8:00 p.m., Thursday, November 27 and by 9:00 p.m. in total 11 feeders were out of service.  Seven line crews were dispatched throughout the evening.  Key problem areas were wind, snow and ice on both power lines and trees.  Lightning was reported in Dartmouth.  At 4:00 p.m. Friday, one crew was able to be dispatched to Stellarton and two crews to Cape Breton.

Sydney Region

The storm reached Cape Breton between 8:00 p.m. and 9:00 p.m., Thursday, November 27.  Ice and wind caused 15 feeders to go out of service as lines broke or came into contact with trees.  Line crews were flown in from Halifax Friday evening and four additional trucks arrived Friday night.  On Sunday, two crews from Stellarton were sent to Sydney.  Key problems, in addition to the ice and wind, were unplowed roads and roads blocked by stalled vehicles.

3.0 Reasons for the Power Outages

There are a number of reasons for the severe outages that occurred in Nova Scotia during the period November 27 and 28, 1997.  In the opinion of the Board, the following factors provided the most significant contribution to these outages:

a) weather conditions;
b) adequacy of the number of personnel;
c) difficulty in reaching trouble spots;
d) adequacy of routine maintenance of distribution lines;
e) protection coordination and system design.


4.0 Weather

4.1 Data Sources

NSPI has stated that weather conditions on November 27, 1997 were such that the effect on certain power lines was the worst experienced in 15 years.  Board Staff was advised by


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Environment Canada that this particular storm was considered average and that the local residents (Pictou County and Cape Breton) have seen far worse.  However, Meteorologist Guy Roussel stated in a newspaper article that the combination of weather conditions that occurred can happen anytime, but rarely does.  Wet snow was followed by a drop in temperature and high winds.  "The wet snow stuck to power lines, poles and trees and began to freeze there.  As it built up and weighed down the lines, wind that would normally whistle through the wires snapped them, plunging thousands of Nova Scotians into darkness," he said.

4.2 Weather Severity

Weather statistics were obtained for the Sydney area from Environment Canada.  Data for the Pictou County area was not available at the time this report was prepared.  However, general news reports suggest that similar conditions existed in the Pictou County area.  These statistics were then used to compare the worst case historical data covering the period 1941 through 1990.

Sydney Area Weather Statistics
  Actual
  Statistics  
Nov. 27
1997
  November  
Avg. Daily
Statistics
1941-1990
Extreme
Statistics
        Level     Date  

Temperature (°C)
Maximum +4 7.1
Minimum -1.6 0.0 -25.6 26/02/1972

Precipitation
Rain (mm) 12.4 4.8 97.3 05/11/1944
Snow (cm) 9.0 0.5 44.5 25/01/1965

Wind (km/h)
(Hourly)
52 21 97 December
1941 - 1990



Page 10




Snowfall
on Ground
(cm)
1997
November 26 2
November 27 0
November 28 12
November 29 13
November 30 12

While the above data clearly shows that the weather on November 27, 1997 was relatively mild and would not be classified as a major storm, the weather conditions experienced were conducive to the build up of ice on the electrical wires and surrounding trees.

An examination of hourly temperature and wind speeds for November 27 and 28, 1997, showed that wind speeds began to increase at a fairly uniform rate beginning around 4:00 a.m. on November 27 and reached 54 km/h by midnight.  Temperatures remained above freezing from 5:00 a.m. through 9:00 p.m. on November 27, 1997.  A fairly rapid drop in temperature began around 4:00 p.m. at which time the temperature was +3.8°C and continued throughout the remainder of the 27th and into the following day, when at 5:00 p.m. the temperature was -3.5°C.

The information obtained does lend credence to the theory that electrical wires, not to mention tree limbs, could have sustained a coating of ice under freezing rain conditions.  Under such conditions, wires, tree limbs and whole trees could very well snap under the increased strain.  It is considered reasonable to assume that the high winds that occurred later in the day could have carried broken tree branches onto the electrical wires, thus resulting, in certain instances, in flashovers between wires.

4.3 Finding

The Board's finding is that the widespread outages that occurred support the theory that the weather, while not severe from a statistical point of view, resulted in widespread icing conditions that resulted in power line damage.  The type of damage that was seen and described is consistent with the following weather effects:

a) electrical wires when coated with ice will cause the wires to sag;
b) sagging wires in some instances will come into contact with other conductors, or trees, and in some instances the ground;
c) electrical wires coated with ice are heavy and will exert a powerful force on the insulators, crossarm and poles that support them.  In some instances this force will be sufficient to bring down the poles;




Page 11



d) the wind that may accompany the freezing rain may cause electric wires to be blown about and occasionally to come into contact with each other;
e) trees will become coated with ice, the weight of which may cause branches to be broken or the whole tree to fall.  Some of these branches or a whole tree may be blown onto the power lines causing a fault, and in some instances bringing down the line; icing conditions and blowing snow will affect the roads and will increase the response times of emergency repair crews.


5.0 Adequacy of the Number of Personnel

5.1 Total Employees

Downsizing has been commonplace in North American utilities in recent years.  Employee statistics were obtained for various utilities from annual reports and telephone conversations.  The following table provides an indication of the extent of the reduction in total numbers of utility employees through both layoffs and attrition (and for comparison purposes also shows the number of customers per employee):

Utility 1990 1991 1992 1993 1994 1995 1996 1997
NB Power
Employees N/A 2,729 2,753 2,700 2,494 2,470 2,463 2,485
Customers (× 1000) N/A 316.1 320.4 325.3 329.8 334.4 337.1 339.6
Customers
per Employee
N/A 115.8 116.4 120.5 132.2 135.4 136.9 136.6
Maritime Electric
Employees 233 235 240 234 191 181 N/A N/A
Customers (× 1000) 50.7 51.3 52.0 52.8 53.6 54.4 N/A N/A
Customers
per Employee
217.6 218.3 216.7 225.6 280.6 300.6 N/A N/A
Central Maine Power
Employees 2,546 2,370 2,376 2,301 2,012 1,811 1,832 N/A
Customers (× 1000) 484.4 490.5 496.7 501.9 507.2 513.1 519.0 N/A
Customers
per Employee
190.3 207.0 209.0 218.1 252.1 283.3 283.3 N/A
Nova Scotia Power
Employees 2,480 2,556 2,437 2,213 2,181 1,935 1,907 N/A
Customers (× 1000) 389.4 395.6 404.9 410.7 415.2 420.0 424.8 N/A
Customers
per Employee
157.0 154.7 166.1 185.6 190.4 217.1 222.8 N/A



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The number of customers per employee provides a measure of staffing levels that permits comparison with other utilities.  In relative terms, NSPI has downsized to a greater extent than NB Power but to a lesser extent than Central Maine Power.

5.2 Total NSPI Lineworkers

The following table shows the total lineworkers employed by NSPI during the period 1990 through 1997, based on data provided by NSPI and the International Brotherhood of Electrical Workers (IBEW):

Reference Source 1990 1991 1992 1993 1994 1995 1996 1997
NSPI 322 311 281 286 287 284 251 253
IBEW
Leading Lineworkers     124   128   107  
Lineworkers     149   159   130  
Apprentices     56   4   0  
Total     329 336 291   237  

It is noted that there are some discrepancies between these numbers.  This could be due to the fact that employee counts were based on different time periods during the year and the methods of accounting for apprentices, inactive, unavailable and temporarily assigned employees.

Another statistic that allows a comparison of personnel adequacy involves the calculation of number of lineworkers per 1000 km of distribution feeder.  Information was obtained from NSPI as well as from other utilities as follows:

In 1997 NSPI had 253 lineworkers, responsible for some 22,843 km of distribution lines.
(11.1 lineworkers per 1000 km of distribution feeders)
The distribution of NSPI lineworkers and the length of distribution lines by region in 1997 were as follows:




Page 13



Region Line
Length
(km)
Line
Workers
Line
Workers
per
1000 km
Western 8,093 77 9.5
Truro 4,126 36 8.7
Stellarton 4,835 44 9.1
Sydney 3,020 43 14.2
Halifax 952 24 25.2
Sackville 1,817 29 16.0
Total 22,843 253 11.1

New Brunswick in 1997 had 206 lineworkers in distribution operations and 74 construction lineworkers for a total response capability of 280 lineworkers responsible for 25,326 km of distribution feeders
(11.1 lineworkers per 1000 km of distribution feeders).

Maritime Electric in Prince Edward Island has a 4,500 km distribution system and an estimated 181 employees of whom 58 are lineworkers
(12.9 lineworkers per 1000 km of distribution feeders).


5.3 General Comments Regarding Adequacy of Number of Personnel

The analysis of benchmark statistics provides a limited indication of the level of adequacy of the work force that must deal with distribution system outages.  This statistical approach, however, does not take into account local terrain, typical weather patterns, work force experience, etc.  An assessment of the adequacy of the work force must also take into account the capability of NSPI to respond to severe outage conditions in a reasonable time, utilizing labour in the most economic manner with due regard to employee and customer safety.  The following data was obtained from information requests and field visits conducted by Board Staff:

During the storms of November 27 and 28, 1997 in the Stellarton area, the 44 available lineworkers were augmented by crews from Metro and Western regions, 4 temporary employees, external contractors and MT&T personnel.



Page 14



The number of full-time lineworkers has fallen but according to NSPI these losses have been partially offset by the redeployment of former supervisory staff to support the line function.


5.4 Findings

The downsizing implemented by NSPI is comparable to that carried out by many North American electric utilities.  This notwithstanding, the Board is of the view that the reduction of lineworkers was a factor in the duration of the outages that occurred in Nova Scotia on November 27 and 28, 1997.

6.0 Difficulty In Reaching Trouble Spots

6.1 Location

6.1.1 Distance of Dispatch Locations from Problem Areas

A comparison was made of the number of NSPI's service regions and dispatch centres in 1990 and 1997.  The four service regions in 1990 have been increased to six regions in 1997.  At the same time that more regions were created, the number of work depots was reduced from thirty-eight to thirty-three.  Depots closed include Caledonia, Pubnico, Dartmouth, Glace Bay and North Sydney.  The latter two areas are now served from Sydney while Dartmouth is now served from Sackville.

NSPI has stated that the only depots that have been closed are those for which alternative service is available within a half hour drive.  All of the work depots are stocked with inventories of commonly used replacement equipment such as poles, insulators, crossarms, etc.  Line crews in the rural areas keep their work vehicles at home overnight, thus reducing response time, according to NSPI.

It was found that a number of feeders in Cape Breton are now about 15 to 20 km further away from a work depot than was the case in 1990 and in certain instances this may have contributed to the duration of outage on these feeders.  On the other hand, some feeders located near a work depot also incurred long outage durations.  For example, part of the Coxheath feeder was out of service for 40 hours, affecting 40 customers.  This 12 kV feeder is 61 km long and about 6 km from the work depot.

6.1.2 Transportation Difficulties

Transportation difficulties were encountered by line crews in trying to reach trouble spots.  These difficulties included icy roads, unplowed roads and roads blocked with abandoned


Page 15



vehicles.  NSPI staff said that the Department of Transportation and Public Works have their own priorities which may delay their response to NSPI requests for particular road clearances.

6.1.3 Communications

The storm that affected NSPI's system had a similar effect on MT&T's system.  In some instances, the similarity of storm conditions resulted in downed communication lines as well as power lines.  In a number of instances, customers thought that fallen communication and cable TV wires were power lines and as such, reported these fallen lines to NSPI, who were then obligated to respond.  This added greatly to the work load of its emergency crews.

6.2 Accessibility

In certain areas of the province, distribution feeders were built through wooded areas in order to capitalize on the shortest distances between points rather than alongside winding roads.  This practice, which has a low first cost, can cause numerous problems during conditions such as those encountered during the last few days of November 1997.  In order to find a fault on this type of line, it is necessary to send personnel to each end of the line.  They then walk toward each other for up to three or four kilometres looking for the fault.  This can often occur at night, and often under stormy conditions.  It is both dangerous and time consuming for personnel.

6.3 Findings

It does not appear that the reduced number of work depots would seriously impact the capability of a line crew to restore power in a timely manner.  The increase in the number of districts since 1990 is a positive action insofar as the maintenance of distribution lines is concerned since management and crews will be able to become more familiar with the smaller service area.

The transportation of emergency crews to the site of faulted or downed power lines is often seriously hindered during winter storms, adding a significant amount of time to the restoration of service.  It is imperative that all emergency service organizations work as a team during major storms.

Reports of downed communication lines are sometimes made to NSPI and must be investigated, thus taking a crew away from productive repair work.


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Distribution feeders that are located in forested areas present hazards to NSPI personnel and greatly slow down the repair process.  Lines should be moved out to roadways where economically feasible.

7.0 Adequacy of Routine Maintenance of Distribution Lines

7.1 NSPI Maintenance Practices

Distribution feeders are inspected every two years.  Guidelines and checklists are used for the inspection process.  All defects are reported and documented in regional files, assigned work order numbers and tracked to completion of repairs.  Maintenance of equipment such as reclosers, voltage regulators and capacitors is carried out every three years or less.  Distribution breakers are maintained on a five-year cycle or as per manufacturers' suggestions.  Substations are visually inspected on a monthly basis and maintenance performed according to manufacturers' recommendations.  Distribution feeder right-of way clearing is prioritized according to historical reliability.  Poles, transformers, wires and hardware are tested as the plant approaches its expected end of life and replaced if required.  Replacement of distribution plant is focused on equipment that may perform poorly and is prioritized based on safety and reliability.  Distribution plant design criteria are based on the C22.3 (Canadian Standards Association) standard.

7.2 Findings

The Board is of the opinion that NSPI's two-year inspection cycle for overhead distribution feeders is reasonable and adequate under average conditions.  More frequent inspections are necessary for older lines or lines more susceptible to failure.

Reclosers, regulators and capacitors are inspected according to manufacturers' recommendations.  Reclosers are inspected more frequently when numerous open and close operations have taken place.  This is a reasonable approach and has the added advantage of bringing a crew along the line more frequently than would otherwise be the case.

The testing of distribution system poles, wires, etc. is performed as the plant approaches the end of its economic life or when called for as a result of the two-year visual inspection procedure.  The Board concludes that testing near the end of the economic life is not always an adequate approach since it is a mathematical approach based on actuarial data and statistics for average lives of mass accounts.  Individual items approaching failure are found at the extremes of the statistical distribution and are not always indicated by data based on averages.


Page 17



Utilization of reliability data is a better way to flag the need for inspection but even this is clearly deficient in some instances.  By the time reliability data indicates a problem, the customers on that line will have been unnecessarily inconvenienced at best and endangered at worst.

The preventive maintenance approach appears to offer the most advantageous approach in that problems must be repaired before they cause a failure.  An example of where the preventive approach is appropriate is the New Campbellton Road single phase distribution feeder in Cape Breton, a portion of which is located near the base of a high hill that is prone to severe erosion.  The line design is typical "rural" and the line cannot be expected to withstand the hostile environment it is in.  In terms of age and good reliability over its life, this line would be expected to easily pass an inspection.  However, the line is subject to tree contact as a result of the severe erosion along the mountain side.  More frequent visual inspections of this type of line would serve to identify future events that could unfold and enable problems to be corrected before failures occur.  The inspection process should also consider the surrounding environment.

8.0 System Design and Protection Considerations

8.1 Data Sources

Board findings are based upon conclusions of the Board Staff field inspections and discussions with field personnel in Pictou County and Industrial Cape Breton.

8.2 Background

The various power systems acquired by the Nova Scotia Power Commission during the 1960s had differing standards of construction.  Over the years, NSPI has been gradually replacing these facilities with new standardized equipment.  However, there appears to be a considerable amount of work yet to be done.

8.3 Protection Considerations

Power systems are designed by balancing reliability considerations with economic considerations.  Ideally, a distribution line should be designed in such a way that faults at points furthest away from the supply substation do not result in the loss of service to the whole line.  This is normally accomplished through the use of fuses, carefully coordinated to minimize the extent of the outage.  If the feeder can be backfed, a series of reclosers can be used to isolate the faulted area.  Finally, remotely operated devices can be installed on the line, such that the line becomes automated (distribution automation).  The latter approach is the most expensive.  However, it provides the ability to control distribution equipment


Page 18



such as line switches and voltage regulators as well as to monitor remote sites for power availability.  Of greater importance, distribution automation permits the implementation of a technology based distribution management system.  NSPI plans to implement a Power Outage Management System which will incorporate distribution automation features and which will be subject to future Board review.

8.4 Findings

The different design standards of the earlier utilities combined with aged equipment, in the view of the Board, has contributed to and is likely to continue to contribute to the frequency of outages in Cape Breton.  NSPI is correct in replacing this sub-standard equipment and should consider accelerating the process of replacement.  Further, poles which are heavily loaded with distribution apparatus should be re-evaluated from a design point of view through a proactive review process.

Distribution capital expenditures as reflected in the annual budgets have decreased by about 16% during the period 1994 through 1997.  NSPI has advised that 1994 and 1995 capital and operating expenditures were at a higher level as a result of system rebuilding, right-of way clearing, tree trimming and distribution maintenance.

The manual inspection of a line during emergency conditions by both lineworkers and non-lineworkers, such as meter readers, can be a dangerous practice.  It is recognized that some non-lineworkers have had training and indeed some may be former lineworkers.  However, the possibility of using untrained personnel does exist.

Further, in the near term, an expansion of the existing Sentry program should be investigated for the determination of fault locations.  This program is well underway by NSPI which reports good success with these remote indication devices.  The Sentry device is a "black box" that connects to both the electrical circuit and the telephone line.  It is capable of calling NSPI when power is lost and serves to identify the area or household without power.

The inspection by Board Staff of selected overhead lines in Industrial Cape Breton revealed the presence of a significant amount of older equipment.  One of the key problems is that the old system standards permitted secondary conductors to be strung in close proximity to one another.  With ice loading and wind, the possibility of the conductors coming into contact with each other increases as the space between the conductors decreases.  In addition, the conductors are old, with the covering broken and hanging in places.


Page 19



9.0 NSPI Reliability Studies

SAIFI – System Average Interruption Frequency Index
    Number of Interruptions per Customer Served, in any selected year
    (Total Customer-Interruptions) ÷ (Total Customers Served)

SAIDI – System Average Interruption Duration Index
    Outage Hours per Customer Served, in any selected year
    (Total Customer-Hours of Interruptions) ÷ (Total Customers Served)

CAIDI – Customer Average Interruption Duration Index
    Average Interruption Duration for Customers Interrupted, in any selected year
    (Total Customer-Hours of Interruptions) ÷ (Total Customer Interruptions)

9.1 Comparison with Other Utilities
SAIFI
interruptions
per year
SAIDI
hours
per year
AIDI
hours
per year
NSPI
(1996)
3.58 6.06 1.69
NB Power
(1996)
4.43 7.60 1.72
Maritime Electric Co.
(1995)
N/A N/A 2.00
Central Maine Power Co.
(1996)
2.27 8.07 3.56
Maine Public Service Co.
(1995)
3.05 3.25 1.06
Atlantic Canada
Average (1996)
4.75 8.25 1.73
All Canada
Average (1996)
See Note below
2.39 2.86 1.20

Note:   It should be pointed out that the "All Canada" data would, in all probability, be strongly influenced by data from large urban centres.


9.2 NSPI Total System Reliability Levels 1990 - 1996
  SAIFI
interruptions
per year
SAIDI
hours
per year
CAIDI
hours
per year
1990 5.48 6.20 1.13
1991 4.95 6.32 1.28
1992 3.91 4.20 1.07
1993 4.23 5.59 1.32
1994 3.41 4.43 1.30
1995 3.24 5.34 1.65
1996 3.58 6.06 1.69



Page 20




9.3 NSPI Reliability Levels by Region (1990 and 1996)

  SAIFI
interruptions
per year
SAIDI
hours
per year
CAIDI
hours
per year
Western Region
1990
1996
6.63
4.12
8.18
8.53
1.23
2.07
Truro Region
1990
1996
4.87
1.93
6.45
5.03
1.32
2.61
Stellarton Region
1990
1996
7.60
6.22
10.30
10.86
1.36
1.75
Sydney Region
1990
1996
8.66
3.79
9.12
6.57
1.05
1.73
Halifax Region
1990
1996
2.08
2.75
1.28
3.36
0.62
1.22
Sackville Region
1990
1996
3.10
3.06
2.43
2.79
0.78
0.91

9.4 Individual Feeder Reliability Levels (1990 - 1996)
The effects of averaging can smooth out (and thus conceal) more extreme measurements for individual feeders.  Reliability data were reviewed for the following three feeders:

a) Merigomish (50N-410) (Stellarton Region);
b) North Sydney (3S-403);
c) New Aberdeen / Glace Bay (81S-306).


The Merigomish feeder has exhibited the most extreme variation in levels of reliability.  Data for this feeder from 1990 to 1996 are as follows:


Page 21



Merigomish Feeder
  SAIFI
interruptions
per year
SAIDI
hours
per year
CAIDI
hours
per year
1990 3.67 6.98 1.90
1991 18.46 30.78 1.67
1992 2.33 3.69 1.58
1993 4.03 11.31 2.81
1994 7.19 22.92 3.19
1995 3.35 4.33 1.29
1996 8.22 34.84 4.24

By way of comparison, data for two coastal area feeders in the Central Maine Power system were provided earlier this year by NSPI.  This information along with the Merigomish, North Sydney and New Aberdeen reliability statistics for 1996 are as follows:

Feeder Reliability Comparison
  SAIFI
interruptions
per year
SAIDI
hours
per year
CAIDI
hours
per year
Nova Scotia Power
Merigomish Feeder 8.22 34.84 4.24
North Sydney Feeder 2.87 4.97 1.73
New Aberdeen Feeder 3.01 2.21 0.73
Central Maine Power
Belfast West Feeder 13.32 50.22 3.77
Bucksport Feeder 5.30 41.34 7.80

9.5 Findings

Customers on the Merigomish feeder are subjected to far more outages and longer lasting outages than most Nova Scotia residents.  This situation has existed for at least the last seven years and shows no sign of improvement.  Feeders, such as Merigomish, that have had SAIDI levels exceeding 10 hours of interruption per year for four years out of seven are prime candidates for immediate action – investigation of the economics of either moving the poorly accessible portions of the line to the side of the road and/or utilizing more sophisticated fault locating technology.


Page 22



Urban reliability exceeds rural reliability.  This is partially due to poor accessibility and a prevalence of older equipment in nonstandard configurations, vulnerability to wind and tree contacts and the lack of second sources of power in rural areas.  In addition, the number of lineworkers in rural areas per km of line is considerably less than in the urban areas.  One of the reasons for this is that more routine construction is taking place in the areas around Halifax, such as feeder extensions, new customer additions and ongoing maintenance.  Urban areas have greater customer density, more underground plant and second source feeds.

NSPI's record with respect to frequency and duration of outages is better than other Maritime utilities, but Maritimers do not enjoy the higher levels of reliability reflected in the "Average All Canadian" numbers.  As mentioned previously, the "All Canadian" numbers are influenced by the larger urban centres.

Based on 1996 statistics, NSPI compares favourably to Central Maine Power with regard to outage duration, but has a greater frequency of outages.  A customer of Central Maine Power can expect an outage to last 3.56 hours compared to NSPI's 1.69 hours.  (It should be noted that Central Maine Power has downsized somewhat more than NSPI – see Section 5.1 of this report).  Central Maine Power has problems with isolated feeders that appear similar in severity to some of the NSPI feeders.

In all regions, a Nova Scotia customer in 1996 who lost power could expect to be without power for a longer period than in 1990, as indicated by the CAIDI index.  The duration of outages as measured by the SAIDI value tends to be longer in Stellarton, Sydney and the Western Regions.  The frequency of outages is greater in Stellarton and the Western Regions than the other Regions of Nova Scotia.

10.0 Customer Communication with NSPI During Emergency

Customer calls to NSPI are directed to the Call Centre at Scotia Square, Monday through Friday (8:00 a.m. - 8:00 p.m.).  After 8 p.m. and on weekends the customer calls are transferred automatically to the Distribution Control Centre which is located at Ragged Lake.  A call-out process is established to staff the Call Centre under emergency conditions.

10.1 NSPI Call Centre
The following outlines events at the Call Centre on Thursday, November 27, 1997 and on the following days:

At 4:00 p.m. on November 27 the Call Centre implemented "standard after-hour outage management procedures."



Page 23



A total of 40 personnel staffed the phone lines between 4:00 p.m. Thursday and 8:00 a.m. Friday and handled about 9,600 calls.  The total number of attempted calls to the Call Centre during this period was 75,829, the majority of which (53,478) occurred between 8:00 p.m. and 12:00 midnight.  Additional staff were called in during these hours.

Early Friday morning, emergency procedures were implemented at the Call Centre, and all 110 positions were occupied throughout the normal business hours of Friday, Monday and Tuesday.

From 8:00 a.m. Friday, November 28, to 8:00 a.m. Wednesday, December 3, 1997, the Call Centre operated on a 24 hour basis utilizing all available personnel.  On average, 51 agents were working throughout the period at the Call Centre.


10.2 Distribution Control Centre at Ragged Lake

The Distribution Control Centre utilizes three operators who are responsible for handling and coordinating emergency distribution operations.  This group also handles customer calls when the Call Centre is not operating in an emergency mode, during week nights (8:00 p.m. to 8:00 a.m.) and on weekends.

10.3 Findings

The existing setup at the Call Centre did not seem able to handle the magnitude of incoming calls experienced (75,829 calls on Thursday evening and early Friday morning).  Interactive Voice Response is currently being implemented and will enable a larger number of calls to be handled through automated response.  Staffing at the Call Centre is based upon normal business hours.  During emergency conditions additional staff are called in.

The importance of inter-organizational communication has been identified as a result of this investigation.  NSPI, MT&T, cable television companies, police, fire, ambulance, Department of Transportation and Public Works, municipal road crews and the media must work in tandem during emergency situations.

Staffing at the Distribution Control Centre seems extremely small for coordinating a series of outages involving a number of regions simultaneously.  This coordination would include not only the initial assessment of regional outage situations, but also the requests for additional lineworkers from various regions and the logistics of moving lineworkers and equipment from one region to another.  While the individual regions would assume the role of outage response, there would still be a requirement for overall coordination amongst regions.


Appendix



Appendix 1
Nova Scotia Power Inc.
T&D Field Service Organization
1997


[T&D: Transmission and Distribution]

Nova Scotia Power T&D Field Service Organization 1997

Note: The field service depot formerly located in Wolfville was moved to Coldbrook in March 1997.
This accounts for the "WOL" symbol attached to the Coldbrook depot.

The electronic version of this information is presented
here for your  information only.   Care has been taken
to transcribe the data accurately, but it is not intended
to   be   relied   on   as   an   authoritative   reference.
The   official   version   is   the   authoritative   source.




1998 February 9

Contemporary Newspaper Reports

(The items below are not part of the UARB Report)






UARB Power Failure Report Made Public

Power Outages Linked to Layoffs

223 Customers per Employee

Utility Board orders
NSP to take steps
to fix problem

In a 36-page report released this day, the Nova Scotia Utility and Review Board said that downsizing at Nova Scotia Power Inc. (NSP) contributed to power outages during a November storm that plunged thousands of homes into the dark.  "The Board is of the opinion that downsizing contributed to the severity of the outages investigated in this study but that was by no means the only cause."

It ordered NSP to investigate and recommend a course of action by Dec. 30, 1998, that will look at some combination of restoring the number of lineworkers to 1994 levels at a minimum and a power management program designed to use the latest distribution automation technology for the worst performing feeder lines.  The report noted the investigation came after complaints to the Board from electricity users who lost power in the November storm and political leaders who also complained about the frequency and duration of power outages over the past few years.

The storm November 27-28, 1997, left some 35,000 customers without power for six hours or longer, including 19,976 in Sydney region on the first day.  Power outages hit 11,000 customers for between 12 and 24 hours; 3,100 for more than 24 hours and the longest outage — 120 people in McCallum Settlement in the Truro region for 73 hours.  During the storm, 59 poles fell and had to be replaced, including six in the Sydney region.  The Board agreed that weather conditions, while relatively mild, resulted in widespread icing conditions that resulted in power line damage.

Downsizing at NSP reduced the workforce to 1,907 in 1996 (1997 numbers weren't available) from 2,480 in 1990.  The cuts left NSP with 223 customers per employee in 1996 compared to 157 in 1990.

Comparing NSP to other power utilities, the Board reported it has downsized more than New Brunswick Power but less than Central Maine Power.  Other findings of the report included:

•  NSP's record with regard to frequency and duration of outages is better than other Maritime utilities but service in this region isn't as reliable as the average for Canada.
•  In all regions, a Nova Scotia customer who lost power in 1996 could expect to be without power for a longer period than in 1990, and the duration tends to be longer in Stellarton, Sydney and the western  regions.
•  NSP's two-year inspection cycle for overhead feeder lines was deemed adequate under average conditions but more frequent inspections are required for older lines or those susceptible to failure.
•  Different design standards of earlier utilities and aged equipment are likely to contribute to the frequency of outages in Cape Breton.  NSP is correct to replace this substandard equipment and should consider accelerating the process.
•  NSP's increase in the number of service regions from four to six between 1990 and 1997 was positive and reduction in work depots from 38 to 33 didn't seriously impact the capability of line crews to restore power.  But a number of feeder lines in Cape Breton are 15 to 20 km further away from work depots than they were in 1990 and in certain instances, this may have contributed to the duration of power outages.


NSP said Monday the report confirms weather conditions caused the severe outages experienced in November.  It said the Board has asked NSP to study other factors affecting reliability of service and it is always interested in learning from outages.  NSP will respond fully to the report within the time frames outlined, said Robbie Shaw, an NSP vice-president.

[Cape Breton Post, 10 February 1998]




Job Cuts Made Blackout More Severe

Utility Review Board Report
Discovers Number of Problems
During November 1997 Outage

If Nova Scotia Power Inc. had pulled the plug on fewer linesmen, an early winter storm wouldn't have left so many homes in the dark for so long, says a report released this day by the provincial regulator, the Nova Scotia Utilities and Review Board, [often called the Public Utilities Board, which was its name 1912-1992].  The number of people responsible for power lines that could stretch halfway around the world has fallen to 253 from 322 since 1990, says the UARB report on how the company provided customer service during power outages in November and December.  "The Board is of the opinion that downsizing contributed to the severity of the outages investigated in this study, but that was by no means the only cause," says the report.

About 35,000 customers lost power for six hours or more, and 11,000 experienced outages of between 12 and 24 hours, says the report.  About 3,100 customers lost electricity for more than 24 hours, and the longest outage of 73 hours hit 120 homes in McCallum Settlement, near Truro.  The storm brought down 59 power poles that had to be replaced.  A second storm hit December 2, but the report focuses mainly on the first one.  While the staff cutbacks are comparable to other North American utilities, the report says "the reduction of lineworkers was a factor in the duration of the outages that occurred in Nova Scotia on November 27 and 28, 1997."

The Board ordered the company to start providing it with summaries of line crew sizes, what it spent on operations and upgrades, and estimates for the next year, beginning in the spring of 1999.

Whether the company will hire more linesmen "depends totally on the outcome of the report," said Nova Scotia Power vice-president Robbie Shaw.  The Board also blames weather conditions, difficulty in reaching trouble spots, the company's maintenance practices, outage protection and system design.

At the time, the company called the November storm the worst it had seen in 15 years.  "The weather was not unduly severe, based on extremes of temperature, wind or precipitation," said the report, noting Environment Canada called the storm average.  "The Board's finding is that the widespread outages that occurred support the theory that the weather, while not severe from a statistical point of view, resulted in widespread icing conditions that resulted in power-line damage."  While the storm wasn't as bad as those experienced last month in Ontario and Quebec, Shaw said "most people in the know would say (it)... was a humdinger."

Line crews had a hard time reaching some trouble spots because of icy, unplowed, and blocked roads, said the report.  The board told the company to file a power outage logistics study that includes co-ordination of NSP activities with emergency services organizations by the end of 1998.  The Board directed the company to "continue and accelerate the program currently under way" to move lines located in forested areas "out to roadsides, where practical."  Where that is not feasible, the board advised the utility to use devices such as the Sentry, which connects the electrical circuit and the telephone line, and can contact Nova Scotia Power when electric power is lost.  The Board told the company to file the estimated cost and work plan for this program by the end of July 1998.

The company's maintenance practices also contributed to the massive outages, says the report.  Its two-year inspection cycle for overhead distribution feeder lines is "reasonable and adequate under average conditions," says the report.  "More frequent inspections are necessary for older lines or lines more susceptible to failure."  Rural lines in problem areas should be checked more often as a preventative measure, says the report.  "More frequent visual inspections of this type of line would serve to identify future events that could unfold and enable problems to be corrected before failures occur."

The Board told the company to research inspection methods being used by North American electric utilities and report back by the end of July 1998.

"I think that may be one of the very few points in the report where we'd like to have further discussions with the (board)," said Shaw.  "Because I think there's not a clear understanding about what our current policy and practice is.  We do inspect everything every two years.  When we see something suspicious or a potential problem, we check it much more often."

The report recommends the company consider strengthening "certain feeders" by using multiple guy wires, larger poles, and insulating for higher voltages.  The Board told the company to file a cost estimate for shoring up its 30 "worst-performing feeders" by the end of July 1998.

The company plans to implement a power outage management system, says the report.  "The various power systems acquired by the Nova Scotia Power Commission during the 1960s had differing standards of construction.  Over the years, NSPI has been gradually replacing these facilities with new standardized equipment.  However, there appears to be a considerable amount of work to be done."  Different design standards and aged equipment "has contributed to, and is likely to continue to contribute to, the frequency of outages in Cape Breton," said the report.  The company "should consider accelerating the process of replacement," and take a second look at poles that are heavily loaded with gear, said the report.  It is to file a report on the plan and associated cost with the Board by the end of July 1998.

But Shaw said there was no difference between the amount of damage to older and newer equipment in the storm.  "We're not absolutely sure about that recommendation," said Shaw.  The company's customer call centre "did not seem able to handle the magnitude of incoming calls experienced (75,829 on Thursday evening and early Friday morning)," says the report.  Shaw said the company is setting up a machine that will answer calls, tell people why their power is out, and when it should come back on.  Nova Scotia Power has to produce the studies recommended by the Board, said Shaw.  "We don't have any choice at all," he said.

[The Halifax Daily News, 10 February 1998]




The Wayback Machine has archived copies of this document:
In the Matter of an Investigation
by the Nova Scotia Utility and Review Board
into the manner in which Nova Scotia Power Inc.
provided service to its customers during
Power Outages occurring on its System
during the months of November and December 1997


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