Restoration Concepts

PEAK RC Training

Classification: Confidential Version No.: 1.5 Date of Document: 10-01-2014 Document Owner/Author: B Pederson

Classification: Version No.: 1.1Date of Document: 8/2015 Document Owner/RC Training Dept.

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Recognize system conditions requiring the application of the RC Restoration Plan.

Learning Objectives

Determine when System Restoration begins and ends.

Identify the duties of the RCSO during System Restoration.

Describe the modes of AGC and when they will apply during system restoration.

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• Recognize Ferranti Effect and methods to reduce effects in transmission system.

Learning Objectives

• Recognize Surge Impedance Loading (SIL).

• Identify requirements for “Return to Normal Operations”.

• Describe “Zero Droop” and the effects of load sharing in an islanded condition.

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o Blackstart Resources are utilized to re-energize a shut down area of the BES, or

o Separation has occurred between neighboring RCs or with the Alberta Electric System Operator (AESO) Area, or

o An energized island has been formed on the BES within the RC Area.

orAdditionally, the RCSO will consider the system to be in an operational emergency condition when any RC Area TOP has implemented their System Restoration Plan(s).

System Conditions forRC Restoration Plan Implementation Scope

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• Coordination

• Monitoring of Progress

• Analyze /

• Stabilize /

• Restore /

• Return to Normal Operations - Discussion

RCSO Roles and Responsibilities

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Identification of Boundarieso What frequency sources are available?

o Are the frequency sources within the island(s) or outside of the island(s)?

o How will accurate values be determined?

Synchronizing / Paralleling

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Islands

Frequency Sources

Balancing Area

Frequency Sources

?

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How will progress be tracked (map, video wall)?

o Ideas? Regional maps available with ability to annotate?

o If on video wall do we know how to log into and manipulate

displays?

Progress Tracking

60.5

60.3

60.42

59.3

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• Transmission Lines, Surge Impedance Loading (SIL), and Ferranti RiseSIL: MVAR produced = MVAR consumed During normal operation, transmission lines are operated above Surge Impedance Loading

(SIL) Lines absorb vars and tend to lower system voltage Generator or Capacitors are used to supply these VARs

During the early stages of restoration, many (if not all) of the lines energized will be operated below (SIL) The lines produce VARs and tend to raise system voltage This is known as “Ferranti Rise” or “Ferranti Effect” Generators or Reactors are used to absorb these VARs

Surge Impedance Loading (SIL) and Ferranti Rise

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VS

ToPowerSystem

ToPowerSystem

Closed OpenMaximum Voltage Will

Occur at Open EndVARS

Flow of Leading ChargingCurrent Leads to a

Gradual Voltage Rise

Voltage Profile Along Line

Closed

Ferranti Rise

Voltage Profile with both breakers closedVR

VARS

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Surge Impedance Loading

The surge impedance loading or SIL of a transmission line is the MW loading of a transmission line at which a natural reactive power balance occurs.

Mvar Produced = 𝑘𝑘𝑉𝑉2𝑋𝑋𝑐𝑐

Mvar Consumed = 𝐼𝐼2𝑋𝑋𝐿𝐿

∴ 𝑘𝑘𝑉𝑉2

𝑋𝑋𝑐𝑐= 𝐼𝐼2𝑋𝑋𝐿𝐿

= 𝑋𝑋𝐿𝐿𝑋𝑋𝑐𝑐 =𝑉𝑉2

𝐼𝐼2

Where XL (=2pfL) and XC (=1/2pfC) arrive at:

2𝑝𝑝𝑝𝑝𝐿𝐿2𝑝𝑝𝑝𝑝𝑝𝑝

= 𝑉𝑉2

𝐼𝐼2= Impedance = 𝐿𝐿

𝑝𝑝= Surge

Impedance

• 0.25 MVAR per mile for 230 kV • 0.75 MVAR per mile for 345 kV • 2.0 MVAR per mile for 500 kV

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Governor Droop

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

Governor Droop

5%5% 5%5%

Hz

Governor droop for different unitsLoad (red box) sharing

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

Hz

MW

Governor Droop

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5% 5%1%

Load sharing between units ofdifferent sizes and droop settings

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.50

58.00

57.00

5% Droop Units with “0” Droop Unit

Hz

MW

5% 0%

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337133

Manual Governor Operation

153

Hz

5% 5%

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Questions ?Next:Generation Operation - AGC

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ACE = (NIA - NIS) - 10β (FA - FS) – IME

Modes of AGC Operation:

Tie-line Bias: Utilizes all of the variables in the ACE equation to control generation

ACE = (NIA - NIS) - 10β (FA - FS)Frequency Bias: Utilizes the frequency portion of the ACE equation for generation control (no schedule component)

10β (FA - FS)Constant Net Interchange: Utilizes the schedules portion of the ACE equation for generation control (no frequency component)

(NIA - NIS)

Area Control Error (ACE) / AGC

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337133153

AGC (Flat Frequency) - Governor Operation

Hz

Flat Frequency Governor Operation

Adding 20 MW of load both systems share.The system in AGC (FF) responds to return frequency to 60 Hz and picking up the20 MW of load added.

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320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337 53133

AGC (Constant Net Interchange) - (Constant Net Interchange)

Hz

Constant Net InterchangeConstant Net Interchange

Adding 20 MW of internal load, both systems share.

The system in which the loadwas added responds by picking up the 20 MW of load added.Frequency is not returned to 60 Hz though.

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320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337

AGC (Flat Frequency) – (Flat Frequency)

Hz

Flat Frequency Flat Frequency

Adding 20 MW of internal load, both systems share.

Both systems try to return frequency to 60 HZ but willovershoot and magnify the frequency delta from 60 Hz.

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320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337 53133

AGC (Flat Frequency) – (Constant Net Interchange)

Hz

Flat Frequency Constant Net Interchange

Adding 20 MW of internal load, both systems share.

FF system works to return frequency to 60 HZ while the CNI system adjust for Interchange. Overshoot occursbut will return to 60 Hz.

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337 53133

AGC (Tie Line Bias) – (Constant Net Interchange)

Hz

Constant Net InterchangeTie Line Bias

Adding 20 MW of internal load, to CNI, both systems share.

The system in TLB responds to return frequency to 60 Hz and CNI picks up the 20 MW of load that was added. Eventuallysettles out to 60Hz.

320400 240 160 80 4000 80 160 240 320

61.50

57.50

61.00

60.50

60.00

59.50

59.00

58.500

58.00

57.00

59.88

133149 3337 53133

AGC (Tie Line Bias) – (Flat Frequency)

Hz

Tie Line Bias Flat Frequency

Adding 20 MW of internal load,both systems share.

The system in TLB responds to return frequency to 60 Hz and schedule, FF controls to 60Hz.Result is overshoot but settlesout to 60 Hz

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Assumptions:

• All RC Area TOPs that have the capability to be interconnected are interconnected and operating synchronously.

• The interconnected RC Area TOPs are connected to the Alberta System or the Eastern Interconnection as appropriate.

• The RCSO has verified that the RC Area BES is in a stable state

Transitioning to “Normal Market Operations”

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Assumptions (cont’d):

• The RCSO has verified with all RC Area BAs and TOPs that they are ready to return to normal operations mode.

• The RCSO has verified the status of adjacent interconnections with the adjacent Reliability Coordinators and AESO and has confirmed that adjacent interconnections are ready to return to normal operations mode with RC Area operating entities.

Transitioning to “Normal Market Operations”

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Priorities:

• The RCSO has verified that the cause of the disturbance that initiated the restoration event is known and is no longer a threat to the BES.

• The RCSO has verified that all major load centers have been restored prior to returning to normal operations.

• Actual BES line flows and contingency analysis results should indicate that the BES is operating within applicable System Operating Limits (SOLs) and Interconnected Reliability Operating Limits (IROLs).

Transitioning to “Normal Market Operations”

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General Procedures:

• The RCSO shall communicate with all RC Area BAs and TOPs (or their designated agent) and verified the status of their systems and that they are ready to return to normal operations.

• The RCSO shall contact AESO and the neighboring RCs to verify that the neighboring RC Areas and adjacent operating entities are ready to resume normal operations with the RC Area’s operating entities.

• The RCSO shall issue a message on WECCNet and RCIS messaging systems announcing a return to normal operations.

Transitioning to “Normal Market Operations”

Questions/Discussion

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Version Date Action By Change Tracking

1.0 08/13/2015 New Training Patrick Olin

1.1 08/30/2015 Converted into correct Peak template for Fall 2015 RC Training. Captivate version removed.

Patrick Olin

Approved: ______________________RC Training Manager Date Signed

VERSION HISTORY:

Versioning History Signature Page

Classification:Version No.: 1.1 Date of Document: 9/15/2015 Document Owner/Author: RC Training