Determining Plant Capacity for a Combined Cycle Power ......General Electric 7FA gas turbines (~150...

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Determining Plant Capacity for a Combined Cycle Power Plant

Using PEPSEJustin Strupp

Scientech, a business unit of Curtiss-Wright Flow Control

Company

2013 Scientech Symposium – Managing Plant Assets and PerformanceClearwater Beach, Florida

August 6-9, 2013

Rex Featherston, Matthew Goodwin, Jason Lee, and

Andre NorwoodArizona Public Service

Company

Redhawk Power Station

Two 2-on-1 Combined Cycles 492 MW Net Base LoadGeneral Electric 7FA gas turbines (~150 MW

each)Supplemental firing in the HRSGAlstom Power steam turbines (~200 MW each) Located in Arlington, ArizonaBegan operating in mid-2002

Problem

Current Operating Assumptions (OAs)Current OA at 2-on-1 base load conditions

-20-15-10-505

101520

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

MW

Effe

ct (M

W)

Operating Assumption - RH 2-on-1 Base Load

Net Maximum Capacity = 492 MW

Solution Needs

Use Ambient ConditionsMonthlyAccurateDocumentedRepeatableDay-ahead and/or Real-timePerformance Monitoring

Background

Operating Assumptions used for dispatch– Max Output– Heat Rate

Current Performance up to date– Degradation and/or Repairs– Ambient Conditions

Power Correction

Power Correction Factor for Temperature and Humidity

Data Collection

PI Data for Ambient Conditions– Temperature– Humidity– Pressure

Collection Intervals and TimeData Collection Schemes

– Monthly Average– Peak Time Monthly Average– Conservative Monthly Outlook– Hybrid Outlook

Ambient Conditions

Monthly Average – average over each month at 4-hour intervals from PI. Similar to current OAs.

14.2

14.3

14.4

14.5

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11 12

Pres

sure

(PSI

A)

Tem

p (°

F) a

nd H

umid

ity (%

)

Month #

Monthly Average

Temperature Humidity Pressure

Ambient Conditions

Peak Time Monthly Average – average over each month using data at 5 PM each day. Peak time scenario.

14.2

14.3

14.4

14.5

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12

Pres

sure

(PSI

A)

Tem

p (°

F) a

nd H

umid

ity (%

)

Month #

Peak Time Monthly Average

Temperature Humidity Pressure

Ambient Conditions

Conservative Monthly Outlook – Peak Time Average adding (Temperature) or subtracting (humidity and pressure) the average standard deviation of the peak time condition for those months to it. Worst case scenario.

14.0

14.1

14.2

14.3

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12

Pres

sure

(PSI

A)

Tem

p (°

F) a

nd H

umid

ity (%

)

Month #

Conservative Monthly Outlook

Temperature Humidity Pressure

Ambient Conditions

Hybrid Outlook – average of Peak Time Monthly Average and the Conservative Monthly Outlook. A different level of conservatism.

14.1

14.2

14.3

14.4

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12

Pres

sure

(PSI

A)

Tem

p (°

F) a

nd H

umid

ity (%

)

Month #

Hybrid Monthly Outlook

Temperature Humidity Pressure

PEPSE - Modeling

Translate Heat Balance and Plant Schematics into PEPSE Components

PEPSE –Schematic With Components

Study Modeling

Tuned PEPSE model to Heat Balances Three operating modes - each month

– 2-on-1 base load– 2-on-1 with max supplemental firing– 1-on-1 base load

Ambient Conditions – monthly for each average ambient condition

Other Modeling Assumptions

Evaporative Cooler considerations– On above 75 °F– Off below 75 °F

Condenser PressurePump PressuresDuct Firing – Max at 1198 °FOthers

2-on-1 Base Load Comparison

440

450

460

470

480

490

500

510

520

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Net

Pow

er O

utpu

t (M

W)

Redhawk 2-on-1 Base Load Comparison

Original OAs Actual Max AveragePeak Average Conservative Outlook Hybrid Outlook

2-on-1 Max Duct Fired Comparison

460470480490500510520530540550560

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Net

Pow

er O

utpu

t (M

W)

Redhawk 2-on-1 Max Duct Fired Comparison

Original OAs Average Peak Average Conservative Outlook Hybrid Outlook

1-on-1 Base Load Comparison

210215220225230235240245250255260

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Net

Pow

er O

utpu

t (M

W)

Redhawk 1-on-1 Base Load Comparison

Original OAs Average Peak Average Conservative Outlook Hybrid Outlook

Recommended Solutions

Which to use as the new OAs for 2-on-1 Base Load, 2-on-1 Max Duct Fired, and 1-on-1 Base Load?– Average– Peak Average– Conservative Outlook– Hybrid Outlook

Additional Work

Next Steps?– Plant data at each Operating Mode– Marketing involvement– Implement Method(s) for OAs– Day-ahead and Real-time instead of Monthly– Performance Monitoring

What could be done for better results?– More Data– Testing– Plant Data Tunes

Questions?