Alberta Power Industry Consortium (U of A )

AESO’s Role In Transmission System Maintenance Standards

John KehlerDirector, Transmission System Performance

November 8, 2012

Discussion on Transmission Maintenance Standards

• Transmission equipment that needs maintenance

• Statistics on equipment maintenance

• Impact on the system

• Laws, Rules and Standards effecting maintenance

• Review of some aspects of system performance

• Questions

Public 2

AESO Mandate - Independent System Operator

• Market DevelopmentDesign a fair, efficient and openly competitive market for electricity.

• Transmission System Development Plan and develop a reliable transmission system that facilitates the competitive market and investment in new supply.

• Transmission System AccessProvide system access for generation and load customers.

• System and Market OperationsDirect the reliable operation of the electricity system and market.

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Alberta’s Electricity Industry

• About 26,000 km of transmission lines

• Single control area of 660,000 km²

• B.C. & Saskatchewan connections

• Over 250 generating units• 10,609 MW system peak• Approximately 160 market

participants• 14,077 MW installed capacity

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AESO Definition of a Transmission Facility

• Transmission Facility is defined in the Electric Utilities Act; AESO uses the same definition in our rules and standards

– means an arrangement of conductors and transformation equipment that transmits electricity from the high voltage terminal of the generation transformer to the low voltage terminal of the step down transformer operating phase to phase at a nominal high voltage level of more than 25 000 volts to a nominal low voltage level of 25000 volts or less, and includes

• (i) transmission lines energized in excess of 25000 volts,

• (ii) insulating and supporting structures,

• (iii) substations, transformers and switchgear,

• (iv) operational, telecommunication and control devices,

• (v) all property of any kind used for the purpose of, or in connection with, the operation of the transmission facility, including all equipment in a substation used to transmit electric energy from

– (A) the low voltage terminal, to

– (B) electric distribution system lines that exit the substation and are energized at 25 000 volts or less, and

• (vi) connections with electric systems in jurisdictions bordering Alberta, but does not include a generating unit or an electric distribution system.

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AESO Definition of Bulk Electric System

• As defined by the Regional Reliability Organization, Bulk Electric System means:

– the electrical generation resources, transmission lines, interconnections with neighbouring systems, and associated equipment, generally operated at voltages of 100kV or higher; radial transmission facilities serving only load with one transmission source are generally not included in this definition

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Transmission Equipment

• Transmission Lines and Towers

• Breakers, Switches

• Busses

• Transformers

• Shunt Devices

• Control Systems (SVCs)

• Relays

• Communication systems

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Substations and Lines

• Transmission Facilities– Over 750 substations that operate at 69 kV+

– Over 1000 transmission lines that operate at 69 kV+

• Bulk Electric System– Over 700 substations that operate at 138kV+

– Over 900 transmission lines that operate at 138kV+

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2011 Outage Statistics

• Based on outages that were 24 hours or less in 2011:– The AESO received over 1400 requests for transmission

facility outages for maintenance purposes

– Outages resulted in up to 8,000 hours where facilities are unavailable to the system

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Impact to AIES Grid and Market Operations

Number of Transmission Constraint Events (Planned

and Unplanned) Per Year

0

100

200

2008 2009 2010 2011

# of

Eve

nts

Annual Generation Curtailment (GWh) Due to Transmission Constraints

0

500

1000

2008 2009 2010 2011

GW

hs

Annual Duration (Hours)

0

4000

8000

2008 2009 2010 2011

# of

Hou

rs

Duration causing curtailment

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Transmission System Maintenance

• When transmission system elements are available, grid and market can operate efficiently

• When transmission system elements are not available, the grid and market can experience constraints which can lead to curtailment of generation and possibly load customers

• Regulated utilities have an obligation serve and there is a need for prudency in the utilities maintenance expectation

• Maintenance costs are approved in the utility General Tariff Application (GTA)

• Maintenance can improve the overall availability, even though the maintenance in itself result in short-term unavailability

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Electric Utilities Act

• Section 39(3)(c)(ii) Duties of transmission facility owners

• 39(3) Each owner of a transmission facility must– (c) inform the Independent System Operator in a timely manner

of anticipated changes in their transmission facility that could affect the Independent System Operator in carrying out its duties, responsibilities and functions, including

• (ii) the status and availability of the transmission facility, including maintenance schedules

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Who does the maintenance?

• Maintenance is done by the transmission facility owner (TFO)

• At a high level, the AESO sees two types of maintenance from TFOs

– Regular Maintenance • i.e. test/calibrate relays, wash insulators, repair

– Capital Maintenance• Rebuild, replace

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The AESO’s Role in Maintenance

• Coordinate (short-term)

• Collaborate (long-term)– AESO Regional planning receives input from TFOs on the

Capital Maintenance programs

– AESO provides input and feedback to TFOs on their Capital Maintenance programs

• Develop Rules

• Implement Alberta Reliability Standards

• Participate in the development of the TFO Terms and Conditions

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ISO Rules

• Generally, ISO Rules require;– The facility owners to design transmission lines for live line

maintenance

– The TFOs to communicate the maintenance outages to the AESO

– The AESO review, conduct risk assessment and approve of the outage

– The AESO to notify participants

– The AESO may need to repost Available Transfer Capability (ATC), enable/ disable RAS etc.

– The AESO to consider cancelling maintenance in Short Term Adequacy assessment

– The AESO to cancel maintenance during emergencies

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Alberta Reliability Standards

• FAC-003-AB-1– Vegetation management on transmission facilities 200 kV+

• FAC-501-WECC-1– Applies to the Alberta-BC Intertie

– Owners must have a Transmission Maintenance and Inspection Plan

• PRC-005 (future)– Protection system maintenance and testing

• PRC-008 (future)– Owners must have a maintenance and testing program for

relays that are part of the Under Frequency Load Shed program

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Alberta Reliability Standards

• PRC-011 (future)– Owners must have a maintenance and testing program for

relays that are part of the Under Voltage Load Shed system

• PRC-017 (future)– Transmission facility owners

must have a maintenance and testing program for relays and equipmentintegral to remedial action schemes

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Terms and Conditions of a Regulated TFO

• Approved by the Alberta Utilities Commission:– The TFO will take reasonable precautions through its

maintenance practices, consistent with Good Electric Operating Practice, to guard against unscheduled interruptions or curtailment in Transmission Services due to facility failure.

– Planned maintenance will be conducted by the TFO according to its maintenance standards

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A Measure of Transmission System Performance

Frequency of Unplanned Outages

69/72 kV Alberta and CEAFrequency Per 100 km

0

6

12

2005-2009 2006-20105 Year Rolling Window

Freq

uenc

y /Y

ear

AlbertaCEA

Alberta

CEA

138/144 kV Alberta and CEAFrequency Per 100 km

0

6

12

2005-2009 2006-20105 Year Rolling Window

Freq

uenc

y / Y

ear

AlbertaCEA Alberta CEA

240 kV Alberta and CEAFrequency Per 100 km

0

6

12

2005-2009 2006-20105 Year Rolling Window

Freq

uenc

y / Y

ear

Alberta CEA AlbertaCEA

500 kV Alberta and CEAFrequency Per 100 km

0

6

12

2005-2009 2006-20105 Year Rolling Window

Freq

uenc

y / Y

ear

Alberta

CEA

Alberta

CEA

Includes 3 pole and single pole trip and reclose eventsPublic 20

Average Outage Duration

69/72 kV Alberta and CEAAverage Outage Duration

0

40

80

2005-2009 2006-20105 Year Rolling Window

Hou

rs

Alberta CEAAlberta

CEA

138/144 kV Alberta and CEAAverage Outage Duration

0

40

80

2005-2009 2006-20105 Year Rolling Window

Hou

rs

Alberta CEAAlberta

CEA

240 kV Alberta and CEAAverage Outage Duration

0

40

80

2005-2009 2006-20105 Year Rolling Window

Hou

rs

Alberta CEA Alberta

CEA

500 kV Alberta and CEAAverage Outage Duration

0

40

80

2005-2009 2006-20105 Year Rolling Window

Hou

rs

AlbertaCEA

AlbertaCEA

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Impact to Delivery Points and Load for Unplanned Outages

69, 72, 138, 144, 240 and 500 kV Systems

Alberta SAIFI

0.0

2.5

5.0

2005-2009 2006-20105 Year Rolling Window

Freq

uenc

y

AlbertaCEA

AlbertaCEA

Alberta Delivery Point SAIDI

0.0

2.5

5.0

2005-2009 2006-20105 Year Rolling Window

Dur

atio

n (H

ours

)

AlbertaCEA

AlbertaCEA

Alberta Delivery Point SARI

0.0

2.5

5.0

2005-2009 2006-20105 Year Rolling Window

Res

tora

tion

Tim

e (H

ours

)

Alberta

CEA

Alberta

CEA

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Questions?

Thank you