Industry Brainstorm on increasing Export Capacity

From Alberta to B.C.

January, 2006

Who participated?

Company Participants

ATCO Power Carl Fuchshuber

Powerex Gordon Dobson-Mack

TransAlta Jim Paton

Ron Strem

TransCanada Bill Hosie

Dan Levson

Larry Sibbald

AESO Jeff Palermo (consultant)

Independent Trent Coroy (consultant)

Purpose of Brainstorm

• Identify as many quality ideas as possible that can increase Export capacity on B.C. Alberta Tie Line

• Brainstorming temporarily suspends critical processes

• Time frame for ideas: 6 months to 5 years• Long lead times on some projects

– Need early identification and initiation• E.g. A solution for 2011 may need initiation now

Purpose of Prioritization Process

• Develop consensus on prioritizing projects based on their cost and benefits in increasing export capacity

• Criteria used to prioritize projects:– Time to implement– How proven is the technology– Approximate cost versus magnitude of export

capacity– Issues that the technology addresses

• Projects prioritized into three groups• Analysis based on Jan 06 industry knowledge of

transmission limitations

Summary of Results

• Three “urgent and important” projects

• Twelve more “important” Priority-1 projects– Consider for approval and immediate

resourcing

• Three – Priority-2 Projects– Need further study and evaluation

• Thirteen – Priority-3 Projects– Park these ideas for review at a later date

• Thermal capacity assessment and upgrades strategy for limiting elements– Thorough inventory of each element of transmission backbone

• Transmission lines (ground clearance, conductor replacement)• Breakers • Current transformers• Busses, jumpers

– Identify lowest cost options to solve limits– Identify database errors, if any, that could create artificial

constraints– Start work immediately as thermal constraints rather than

dynamic constraints are currently limiting exports

Urgent Project 1

Urgent Project 1b

• Create transmission limitations document– Limiting operating criteria– Limiting contingencies by facility– Consequence of each contingency– Action required to mitigate limitations– Cross references to support studies

Urgent Project 2

• Expanded Remedial Action Schemes– Develop a North South GRAS (underway?)

• Triggered by loss of ATC limiting double circuit or single circuit line outages

– Develop a 500 kV BC Tie RAS to mitigate loss of ATC limiting double or single circuit line outages

– Expand the use of undervoltage relays in a RAS to prevent voltage collapse

– Develop Generator MW ramp down scheme to automatically respond to thermal line overloads (which have a longer response time)

Urgent Project 3

• Thermal Monitoring – Indirect Sensors– Use indirect sensors such as weather stations

to monitor weather, sunlight, temperature and wind

– Use these indications to create a real time assessment of thermal limits on the system

– Proven technology– Capacity should be higher during:

• Cooler days, night time, windier conditions• Risks are higher during storm conditions

Other Priority-1 Projects

1. Tie tripping export shedding scheme– Automatically ramp down exports when

voltages fall below predetermined levels2. New 500 kV reactor breaker at Langdon

– Reactors can be switched out pre and post events to support southern Alberta voltage

3. Encourage more north south capacity increases

4. Explore BC side solutions5. BCTC AESO coordination

Other Priority-1 Projects – cont.

6. Rebalancing north-south corridor lines– use phase shifters, new switching stations

7. Increase conductor capacity– Use new high capacity conductor technology on

critical lines8. Over-frequency generation shedding scheme

(over 800 MW)9. Saskatchewan Tie enhancements

– Sask Tie can modulate voltages, RAS to increase exports to Saskatchewan on a BC Tie trip, increase imports for southern Alberta undervoltage concerns

Other Priority-1 Projects – cont.

10.Use weather adjusted criteria– Use N-2 criteria only during adverse weather

conditions (when almost all contingencies occur), otherwise use N-1 with safety nets

11.Use real time current measurements– Replace proxies like MW, use actual current

12.Operate systems on Live database of system conditions– Use pre-calculated limits under various conditions– Flows limited on pre-calculated contingencies, not

settings

Lower Priority Projects

• Three - Priority 2 Projects– Need further study and evaluation

• Twelve – Priority 3 Projects– Park these ideas for review at a later date

• Key caveat on prioritization– If AESO sees more merit in any of these 16

projects, priority could be increased

Conclusion

• Process was worthwhile

• Will likely be the first of many over the next 5 years as north south capacity becomes tighter

• Based on current knowledge of the cause of limitations on the system

• Thanks to AESO for its support of this brainstorming process