Refurbishment & Upgrade of the Celilo HVdc Converter Station

Mark A Reynolds, PE

Sr. Project Manager, POWER Engineers

mark.reynolds@powereng.com

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Karl A Mitsch, P.E. Sr. Project Manager USDOE – Bonneville

Power Administration kamitsch@bpa.gov

Presentation Topics

• BPA Decision – Replace or Refurbish

• Typical Life of HVdc Equipment

• Project Approach Consideration and Timeframe

• Develop Risk exposure

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Factors Effecting Equipment Life

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• MW load factor of HVdc link

• Maintained to HVdc OEM recommendations

• Design specification for equipment

• Fault and external stresses on equipment

• Overload stresses on equipment

Typical Equipment Life

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Equipment Life (years)

Thyristor Valves + Electronics 35+

Converter Transformer 35+ (varies on MW Loading)

Filters 35+

Control & Protection 15+

Cooling Equipment 35+

Smoothing Reactors 35+

Controls Lifecycle (Ideal)

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• 1 – 5 yrs – Under OEM support

• 6 – 12 yrs – Mid life of controls

• 13 –14 yrs – Replacement planning

• 15 –17 yrs – Procure and replace controls

BPA Decision – Replace or Refurbish

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• Equipment condition & maintainability – Increasing failure rate suggesting end of life – Significant increases in maintenance costs – Spare parts not available – Availability of HVdc OEM support

BPA Decision – Replace or Refurbish

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• Outage Considerations – Replace

• Build adjacent, cutover (minimize outage time)

– Refurbish

• Multiple projects over time (look at collective outage impacts)

• Provide incentives to minimize outage time

• Refurbish and operate in monopole configuration to reduce outage impact

– Replacement power can be very expensive

The BPA Decision & Scope

• Owners Decision – Replace HVdc Terminal Facilities at the Northern Terminal (Celilo)

• Upgrade Link Capacity by Current & Voltage Increases (3410 Amperes, at 560 kV, 3800 MW (Ultimate Rating), 3100 Amperes, at 556 kV, 3450 MW (Phase 1-Rerate))

• Transmission Insulation Upgrade by insulator bell additions ( 2~3 bells on 804 structures)

• Controls Replacement (pre-replacement) control telecommunications changes (analog MW to Digital)

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BPA Project Approach

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• Define Project & Funding

–Get HVdc OEM cost estimates

– Life Cycle Cost of Replace vs. Refurbish

–Current and future operating expenses

–Down time or outages needed (replacement power costs)

Project Approach

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• Technical Details

– Establish New Converter Ratings (step plan for rerating)

– MW transmission line ultimate rating (3800 MW)

– Develop a separation and cut-over plan

Insulator I-String Additions

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Design & Manufacturing of New HVdc Apparatus

• Converter Transformers

• Converter Valves (Thyristor)

• Control Systems

• Cooling Plant

• Instrument Transformers

• Air Core Smoothing Reactors

• Other Equipment

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Transformer Production

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New Thyristor Valve Under HV Testing

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Existing Converter 1 & 2 Switchyard Demolition

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Movement & Installation of New Converter Transformers (430 Ton Transport Weight)

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New Converter Transformer Installation 770 MVA, 3-Winding, 1,270,000 pounds

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New Switchyard Installation

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New Thyristor Valve Tower Installation

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Controls Systems Testing

• MACH-3 Factory System Testing in Ludvika Sweden

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Celilo Project Schedule

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Installation Testing & Commissioning Program

• Subsystem Testing & cable checks

• Pre-Energization control checks including Interlocks and sequence checks

• Finalize Energization Sequence& Outage Coordination Planning

• Partial Load Testing

• Full Load Testing

• Staged Line Faults and Performance Testing

• 30-Day Trial Operation (90 Day Maximum)

• Commercial Acceptance & Celebration

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Detailed Commissioning Milestones

• 9/13/15 – Connect new converters to 500 kV AC system and perform “Back to Back” testing**

• 10/3/15 – Start of PDCI Outage for DC Line Upgrades and reconnection of DC line to new converters

• 11/3/15 – End of PDCI Outage

• 11/15/15 – Exchange of power with Sylmar via one pole is possible

**A local Northern Terminal End “Back to Back” connection will allow the BPA 525 kV HVac Feeders to energize the new converters No. 1 & 2 on the ac side of the new Poles. The HVdc Poles No. 1 & 2 will then be “cross connected” on the HVdc side providing a “local loop” at a North Terminal local station to allow a of test the new poles at Celilo, at full voltage and nearly full power levels, with minimal impact to the WECC Network. Only energy losses during the BtB operation will need to be purchased by BPA.

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Back to Back Testing Configuration

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Thank you for your time