MVAR control, integration of wind generation to grid,

plausible solutions for supporting quality power and reliable grid in

free markets Diran Obadina

Principal, Systems Development ERCOT

July 29, 2015 Paper Number 15PESGM2585

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Current Records – July 15, 2015

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Peak Demand Record: 68,305 megawatts (MW)

68,305 MW, August 3, 2011

Weekend Record

65,159 MW, Sunday, August 28, 2011

Winter Peak Record: 57,265 MW

57,265 MW, February 10, 2011

Wind Generation Records (instantaneous)

11,154 MW, February 19, 2015, 10:52 p.m.

- Non-Coastal Wind Output = 9,872 MW

- Coastal Wind Output = 1,282 MW

- Supplying 34.2% of the load

- Active Wind Capacity = 13,370 MW

• 40.58% Wind Penetration, March 29, 2015, 2:12 a.m.

- Total Wind Output = 10,308 MW

- Total Load = 25,400 MW

June 2015 Demand

- 61,732 MW, June 10

June 2014 Demand

- 59,786 MW, June 30

Wind Generation – June 30, 2015

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816 977 1,173 1,3851,854

2,875

4,785

8,0058,916

9,400 9,60410,407

11,065

12,47013,424 13,424 13,424

2,941

5,5935,593

3,5904,390

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816 977 1,1731,385

1,854

2,875

4,785

8,005

8,9169,400

9,60410,407

11,065

12,470

16,365

22,607

23,407

0,000 MW

5,000 MW

10,000 MW

15,000 MW

20,000 MW

25,000 MW

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Cumulative MW Installed IA Signed-Financial Security Posted IA Signed-No Financial Security

The data presented here is based upon the latest registration data provided to ERCOT by the resource owners and can change wi thout notice. Any capacity changes will be reflected in current and subsequent years' totals.

Scheduling delays will also be reflected in the planned projects as that information is received. This chart reflects planned units in the calendar year of submission rather than installations by peak of year shown.

Financial security posted for funding interconnection facilities does not include CREZ security deposits, which are refunded to the Interconnecting Entity when an IA is signed.

ERCOT Wind Installations by Year (as of end of June 2015)

Cumulative Installed and Planned Solar Capacity

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193 193 193

7,563

10,153

15 42 82 121 191 288

7,756

10,346

0

2,000

4,000

6,000

8,000

10,000

12,000

2010 2011 2012 2013 2014 2015 2016 2017

Cumulative MW Under StudyCumulative MW Installed

Megawatts

95

COMPETITIVE RENEWABLE ENERGY ZONES

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Challenges of Voltage control

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• Large wind power farms with little or no local loads

served and/or large synchronous machines in the

zone affecting system stability

• Long, highly compensated 345KV transmission lines

to load centers in the north and east;

– Critical voltage at voltage collapse point is relatively high which

could put the system at risk even when the voltages are within

normal ranges

• Multiple wind resource and transmission owners

– Consideration of fairness in a competitive environment.

Wind Power vs 345 KV Voltage

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Proposed Framework

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Reactive Resource Scheduling

Contingency List

Load Forecast

SCADA EMS

Wind Forecast

Outage Schedules

Transmission Operators

Real time Reactive Dispatch

Current Operating

Plan

Reactive Resource Scheduler

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• Schedules switchable reactive devices over multiple hours into the future

• Objective is to minimize number of switching needed over the scheduling horizon in order to maintain voltage

• Maintain adequate reactive reserve in defined reactive areas

• Executes in the day-ahead following RUC and then hourly to refine the day-ahead schedules

Scheduling Horizon; Scheduling Interval; Load Curve

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time Scheduling horizon (T)

Fore

caste

d L

oad

-C

urv

e

…

…

Reactive Resource Scheduling Objective

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Reactive Resource Scheduling

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• Scheduling Horizon: 12-24 hours

• Scheduling Interval: 30-60 mins

• Works with the RT Reactive Dispatch

• Maintains adequate reserve with the voltage

control area

Reactive Resource Scheduler - Controls

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• Shunt Capacitors

• Shunt reactors

• Line switching

• Unit commitment

• Invokes Reactive Dispatch

Real Time Reactive Dispatch

• Executes in the Real Time Sequence

• Objective – Manage the voltage across the ERCOT grid – Secure base case voltage ranges throughout system

– Maintain post contingency voltages

– Restore post-event secure voltage profile

– Minimum shift/minimum number of controls objective function

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Real Time Reactive Dispatch - Controls • Generator AVR Target Voltage

• Synchronous Condenser AVR Target Voltage

• SVC Target Voltage

• On-line Transformer Taps

– Tap position

– Target voltage

• Invokes the Reactive Resource Scheduling (RRS) in case of infeasibility

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Thank You!

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