mca13sgr s500 mica gis intervenor workshop aug 25 2009 …...mica gas insulated switchgear • gis...

Mica Gas Insulated Switchgear (GIS) Replacement Project Workshop26 August 2009

B-3

markhuds

BCH_Mica Gas Insulated Switchgear Project

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Agenda – Mica GIS Replacement Project

• BCUC Order • Mica Generating Station and GIS equipment• Need for the Project• Project Scope and Cost • Architecture Evaluation and Decision Making• Timing and Sequencing• Project Risks• Rate Impact• Consultation• Conclusions

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Order Sought from BCUC

• 44.2 (3) (a) of the Utilities Commission Act (the UCA) • BCUC acceptance that the expenditures to replace the aging

GIS at Mica with new GIS equipment by 2013 are in the public interest

• Considerations:> the Government’s energy objectives; > BC Hydro’s most recent long term resource plan; > whether the expenditure schedule is consistent with section 64.01 and

64.02 of the UCA in respect of electricity self sufficiency and clean and renewable resources; and

> the interests of present and future ratepayers.• Project costs:

> Expected cost: $180.6 M> Authorized cost: $200.2 M

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Mica Generating Station is on the Columbia River 135 km upstream from Revelstoke.

Mica Generating Station

Mica Generating Station and GIS Equipment

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Mica Generating Station

• Mica supplies 16% of energy & 17% of capacity for BCH.• The expected cost of a forced or unplanned outage in any month could range from $0 to $20 million per month depending upon time of year and other conditions.• Replacement energy and capacity may need to be purchased from the market.

Underground powerhouse


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Lead Shafts 1- 3

• Mica 500 kV Switchgear conducts energy from the underground transformers to the transmission system at the surface.

• Energy is conducted via “Lead Shafts”. Lead Shafts are tunnels running between the powerhouse and surface.

Mica Gas Insulated Switchgear


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Mica Gas Insulated Switchgear

• GIS allows high voltage conductors to be deployed in limited spaces such as those in an underground powerhouse

• Sulphur Hexaflouride (SF6) is the insulating gas that allows theequipment to be compact when compared to air insulated switchgear.


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Mica Dam and Generating Station

• 3-D –Animation Video


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GIS Equipment: GIS Bus

ConductorBus Cone Insulator

Cut Away of GIS Bus

• Gas Insulated Bus includes:1. An inner conductor,2. SF6 insulating gas3. Outer housing

• Epoxy cones support conductor and insulate between conductor and housing.


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GIS Equipment: GIS Bus

• 3 phases of GIS Bus in Lead Shafts

• Total of 1200 m of Bus in Mica


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GIS: Disconnect Switches

GIS Bus

• Disconnect switches are used to isolate sections of the 500kV system.• Disconnect switches are manually operated.


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GIS: Circuit Breakers

A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload.


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GIS: Surge Arrestors

Surge arrestors protect transformers and other equipment from over voltage spikes.


Surge arrestor beingrepaired in 2008

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Need for the Project:Independent GIS Condition Assessments

Key conclusions of independent assessments• BC Hydro can expect prolonged, multi-unit outages with the current

switchgear;> Disconnect switches and majority of bus in the transformer chamber require two unit

outages for repair work to proceed.• Surge arrestors and disconnect switches present the greatest risks;• Failure of the GIS in one lead shaft restricts the output to 1,500 MW

> During the repair period for such a failure, Mica is vulnerable to a full plant outage if a second GIS failure occurs

• There is a 99 % chance of GIS failure within ten years > Nine months after this prediction, a surge arrestor failed on Unit 3, which resulted in it

being out of service for ten weeks.• The Mica GIS is > 30 yrs old. It may be the last 500 kV GIS

equipment of its type still in operation in North America.

Need for the Project

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Need for the Project:Condition Assessment Conclusions

G1

T1

Equipment is in GOOD Condition

Equipment is in FAIR Condition

Equipment is in POOR Condition

Equipment is in UNSATISFACTORY

Condition

Circuit Breaker

Disconnect Switch

Transformer

Generator

Surge Arrester

Transmission Line

Reactor

5L71 5L72

T2 T3 T4

G2 G4G3

Note: Circuit breakers in the Switchgear Building were replaced in 2007 and 2008 due to their unsatisfactory conditions.

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Project scope

• Replace the original 500KV Gas Insulated Switchgear at Mica

• Develop a system that provides benefits by improving upon the current 500KV switchgear.

Project scope and cost

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Project Benefits• Develop a more robust

architecture than the current architecture> Improved layout

• Disconnect switches> Remote operation

• Maintenance access• Environmental benefits

> Reduce SF6 leakage to <0.5% per year.

• Mica 5 & 6 > Enables BCH to maintain

Contingency Resource Plan (CRP) dates for Mica 5 & 6.

New Switchgear will be meet “Safety by Design” requirements. The Switchgear will be floor mounted. It will be accessible using

a new overhead crane.


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Project Cost

$200.2Total Authorized Cost (note 6)19.6Project Reserve (Note 5)

$180.6Total Expected Cost7.5Identification and Definition Phase (loaded)

$173.1Sub-total: Implementation Phase Cost (Loaded) 21.3Interest During Construction (Note 4)

17.7Capital Overhead (Note 3)

$134.1Sub-total: Implementation Phase Cost (Direct)8.4Inflation and Escalation (Note 2 )

1.0Dismantling and Removal

11.3Contingency on Expected Cost

$113.4Sub-total: Construction Cost before Contingency (Note 1)18.8Project Management and Engineering

$ 94.6Direct Construction Cost

AMOUNT($ million)

PROJECT COMPONENT


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Agenda – Mica GIS Replacement Project

• BCUC Order • Mica Generating Station and GIS equipment• Need for the Project• Project Scope and Cost • Architecture Evaluation and Decision Making• Timing and Sequencing• Project Risks• Rate Impact• Consultation• Conclusions

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Project Requirements (summary)

• Maintain the reliability of the500kV GIS

• Realize project benefits:> Robust architecture> Disconnect switches> Maintenance access> Environmental benefits

• Develop a system level design that can be implemented without significant impacts upon the operating generating station

• Low life cycle cost

Architecture Evaluation and Decision Making

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Architecture Evaluation

Revolutionary Architectures that did not include GIS were:1. moving the 500 kV transformers out of the Mica powerhouse to the surface;2. using an insulating gas other than SF6.

• Conclusions: Not viableEvolutionary Architectures were developed:

• Evolutionary switchgear designs were developed for more detailedconsideration.


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Structured Decision Making Process

Final Structured Decision

making and ranking

Detailed Study, Estimating

Engineering Study

Engineering Analysis and

Constraints


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Recommended Architecture

Not in the scope of this project

Style Legend

Not In Scope

Replace

Remain

G1

T1

Circuit Breaker

Disconnect Switch

Transformer

Generator

Surge Arrester

Transmission Line

Reactor

5L71 5L72

G2

T2

G3

T3

G4

T4

G5

T5

G6

T6

New

• New architecture substantially reduces consequences of future failures.• Lead shaft 3 improves system reliability and has construction benefits.• Architecture allow the realization of the additional project benefits.

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Replacement SequencingSchedule for GIS component Installation/Replacement

1 2 3 4 5 6 7 8 9 10 11 12 13Low Cost

($6 M)Moderate

Cost ($12 M) High Cost

($19 M)

Activity 2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

Probability(33%)

Moderate Probability

(25%)

Low Probability

(15%)Alternative 1

Replace Existing GIS $61Lead shaft 3 and interface $56

PV of project costs $117 $117 $117 $117Range of Outage costs $5 $8 $8GHG Credit Cost $1 $1 $1Range of Adjusted PV of Project $123 $126 $126

Alternative 2 a

Replace Existing $54Lead shaft 3 and interface $53


Alternative 2 bReplace Existing $46Lead shaft 3 and interface $53


Alternative 3Replace Existing $65Lead shaft 3 and interface $53


Do Nothing - Defer implementaion of Project by 5 years

PV Project and Outage Costs(in $millions)

Outage probability increasing by 1% per year

Implement project piecemeal over time

Do Nothing - Defer implementaion of Project by 10 years

PV Project

Cost

Full implementation of Project by 2013

Alternative 4Replace existing GIS in tranformer chamber and switchgear building

$42

Lead shaft 3 and interface $56Lead shafts 1 and 2 $20


Same as Alternative 1 but defer replacement of lead shafts 1 and 2

Recommendation

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Option/ Year

Present Value Cost ($millions) 20

10

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

$117 x x

$124 x x

$127 x x x x

$119 x x

$118 x x

$114 x x x x

$116 x x

LEGENDLead Shaft 3 and switchgear buildingLead Shaft 1Lead Shaft 2Base ComponentsPlanned Outage - 4 months xMica Unit 5 In-service date

MIC

A 5 IS

D

MIC

A 5 IS

D

5) Defer Lead Shaft 1&2 ten years

6) Defer Lead Shaft 3 ten years

7) Defer Lead Shaft 1 ten years

MIC

A 5 IS

D

1) Base Case - Do All Now

2) Defer Lead Shaft 1&2

3) Defer Lead Shaft 3

4) Defer Lead Shaft 1

Sensitivity Analysis of Mica 5 ISD

Option 1 is lowest cost riskregardless of Mica Unit 5In Service Date

Timing and sequencing

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Construction Sequencing Animation

Timing and sequencing

27Mica Switchgear Project 1

Mica Switchgear Project Schedule July 09 –Dec 09

Lead Shaft 3

Jan 10 –Jun 10

Jun 10 –Dec 10

Jan 11 –Jun 11

Jan 12 –Jun 12

Jun 12 –Dec 12

Jan 13 –Jun 13

Stage 1

Stage 2

Stage 3

Jun 11 –Dec 11Design &

Manufacture

Stage 4

Stage 5

Stage 6

Stage 7

Stage 8

Stage 9

RingSwitchgear Building Ring Extension

Lead Shaft 3

InterfaceInterface existingGIS to Lead Shaft 3

Unit 3 & 4Mica Units 3 & 4

RingSwitchgear BuildingRing Bus

Units 1 & 2Mica Units 1 & 2

RingSwitchgear BuildingRing Bus

Lead Shaft 2 LS 2

Lead Shaft 1 LS 1

Completion CompletionSequencing of the work minimizes disruption to the operating plant. Replacement of the GIS for Units 1 – 4 can be completed in the spring of 2011 and 2012 when outage costs are low.

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Project Risks

• Cost risks mitigated by BC Hydro’s decision to tender early and obtain firm pricing

• Schedule risks are mitigated by:> Including lead shaft 3 to reduce outage time and increase reliability during

construction> Apply CHC Collective Agreement

• Safety risks during construction are mitigated by:> BC Hydro and Contractor Safety Management Plans> Site Specific Safe Work Procedures> Monitoring by BC Hydro during construction

• Environmental risks are mitigated by:> Environmental Management & Environmental Protection Plans> During construction BC Hydro will have an on-site Environmental Monitor.

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Annual Incremental Rate Impacts

0.00%

0.10%

0.20%

0.30%

0.40%

0.50%

0.60%

2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 2032

Fiscal Year

Per C

ent

Expected

Approved

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Consultation

• BC Hydro has undertaken consultation with First Nations and with public stakeholders to identify issues specific to the Project.

• BC Hydro expects the Project will have minimal, if any adverse impacts. > Project will be implemented within Mica GS or on previously

disturbed ground. > There will be no impact on the Kinbasket or Revelstoke reservoirs.

• BC Hydro believes that the consultation conducted for the Project is adequate.

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Conclusions

• BC Hydro is seeking BCUC acceptance that expenditures to replace the aging GIS at Mica with new GIS equipment by 2013 are in the public interest. Project costs are:> Expected cost: $180.6 M> Authorized cost: $200.2 M

• The condition of the original Mica 500kV switchgear poses the risk of forced outages

• The project will:1. replace the 500 kV GIS; and 2. improve upon the current GIS system.

• BC Hydro has planned work so that costs are understood• BC Hydro has identified and is managing project risks.

mca13sgr s500 mica gis intervenor workshop aug 25 2009 …...mica gas insulated switchgear • gis...

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