Second Wind Generation Workshop
Sand Bluff Wind Farm – Gamesa G87 Turbine
John Franklin,
Vice President, Operations,
E.ON Climate & Renewables North America
August 22, 2008
Gamesa G87 Wind Turbine
Physical Characteristics –
-
Three blade, upwind design
-
Pitch regulated variable speed
-
Active yaw
-
78 M Hub Height
-
42.5 M Blade length
-
9.0 – 19.0 rpm
-
Asynchronous, 4 pole, doubly fed wound rotor generator, 690 V
 Rating
- 2000 kW
- 60 Hz
- 1500A @ 690 V
Turbine
Wind Farm Description
Transmission /Interconnection
Typical Operating Day
Data/Communication Flow
Gamesa G87 Wind Turbine
Starting – 4.0 m/s cut in wind speed. Turbine PLC manages blade pitch angle hydraulically for
monitored wind conditions and adjusted by turbine power controller to optimize rotor speed and pitch
angle for maximum power.
Controlling Power Output – SCADA set point controlled and operator adjustable. Park power output
controlled by blade pitch angle down to 40% , below 40% individual turbines are shut down by the park
controller to achieve park output set point.
Stopping – 25m/s cut-out wind speed, resets at 20m/s. Turbine PLC manages the controlled stop by
pitch angle adjustment and brake application.
Reactive devices as part of the turbine – Standard power factor is unity as
measured at the low voltage side of the nacelle transformer
at all active power ranges. Gamesa has static capacitors
onboard each WTG which are not operator accessible.
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Gamesa G87 Wind Turbine
Control – Asynchronous generator with wound rotor, slip rings, two 4 quadrant converters with IGBT
switches, contactors and protection
SIMPLIFIED DIAGRAM
Turbine
Turbine
Wind
Wind Farm
FarmDescription
Description
Transmission/Interconnection
Interconnection
Typical Operating Day
Data/Communication Flow
FERC Order 661-A Transition Period LVRT Standard compliant.
Gamesa V87 LVRT Capability
- Procurement Contract executed December 2005
- Interconnect Agreement signed November 2006
- Scheduled in-service date July 2007
Vn
EVENT T0
100 %
Nominal Voltage
75 %
45 %
15 %
0
150
700
1500
3000
mS
Time (milliseconds)
Turbine
Slide 5
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
SAND BLUFF WIND FARM
Location: Big Spring, Texas
• 90.0 MW
• 45 Gamesa G87 2.0 MW Wind Turbines
• 3 Land Owners
• Project Area: 10.5 square miles
• Grid Voltage 138 kV, McDonald Substation
• Mean Wind Speed 8.5 m/s
• Capacity factor (P50) 41.2%
• Annual MW hrs 325,000
Turbine
Wind Farm Description Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Site Selection Criteria = Good Wind, Transmission Access, Willing Landowners
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
SUBSTATION SINGLE-LINE DIAGRAM (SIMPLE)
TDSP STATION
GENERATOR STATION
- 138kV OVERHEAD
- 100 MVA GSU w LTC – 138/34.5 kV
- 3 – 10 MVAR CAPACITOR BANKS
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
COLLECTION SYSTEM ONE LINE
Overhead 34.5kV
Underground 34.5kV
45 Gamesa G87-2.0Mw
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Sand Bluff Power Factor at 138kV Metering Point
Sand Bluff Production, MW vs. MVAr
30
20
MVAr
10
0
0
10
20
30
40
50
60
70
80
-10
-20
-30
MW
0.95
Turbine
Wind Farm Description
Transmission/Interconnection
-0.95
Data
Typical Operating Day
Data/Communication Flow
90
Sand Bluff Voltage Control at 138kV Metering Point
Sand Bluff Production, MW vs. kV
147
Requested 142kV -144kV
145
144kV
Voltage (kV)
143
142kV
141
139
137
135
0
10
20
30
40
50
60
70
80
MW
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
90
Control Systems
SCADA Control of WTG’s, Wind Farm and HMI control of substation breakers and capacitor banks.
Local on site at Wind Farm Service Building
Primary remote 24/7 at Austin Operations Center
Back-up remote at Roscoe Emergency Operations Center
Austin Operations Center
24/7 Operator attended control center
Full SCADA control of all EON Wind Farms
Direct line to ONCOR Operations Desk
QSE to AOC communication and response meets ERCOT response time requirements for all actions
- Curtailment/Release
- Voltage Control
- Reactive deployment
- Changing control settings
Turbine
Wind Farm Description Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Control System Location & Facilities ►E.ON 24/7 Austin Operations Center
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Transmission & Interconnection Issues
 Special Protection Scheme (SPS)
The substation is equipped with a Special Protection Scheme (SPS) to
signal the wind farm to curtail generation in response to abnormal
conditions on the Oncor transmission system.
Loss of line either T-line section ( McDonald- Sprayberry or McDonald –
Morgan Creek) initiates SPS if remaining line section rating is exceeded.
SPS activation produces first level action (from T-0 to T+23 s) initiating
back down of Sand Bluff WTG output to 60Mw via SCADA, second level
action ( T+ 24 s) initiates trip of one Sand Bluff feeder breaker, third level
action (T+28 s) trips Sand Bluff/Forest Creek 138kV bus breaker.
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Data/ Communication Flow & Physical Activities (typical day)

Submitting Resource Plan
▪ Done through QSE - Present day update and day ahead Production Forecast
submitted to QSE by 0830 daily.
- Resource Plan submitted to ERCOT daily.

Responding to Curtailment Order
- QSE receives OOME instructions for next interval or immediate action
- QSE relays dispatch instruction to EON 24/7 Operations Center

- EON Dispatcher executes instruction
Release from Curtailment Order
- Same process as above
Turbine
Wind Farm Description
Transmission/Interconnection Typical Operating Day
Data/Communication Flow
COMMUNICATIONS FLOWCHART
ERCOT
QSE 24/7
< 10 minutes
EON 24/7
COMPLETE
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day Data/Communication Flow
ERCOT
Generator Information Flow
Day-Ahead: Generation
Schedule for next day
Day-Ahead: Expected next day
Day-Ahead: Confirmation of
MW Output, Forecasts
Next-day Schedules
Day-Ahead: ERCOT
Generator Instructions, if any
EC&R
WTG
24/7
Operations
Up to 2 hours in advance:
Up to 2 hours in advance:
Resource Plans issued revising
Day-Ahead Schedule
Revised expected output
based on nearer-time forecasts
Realtime:
Realtime:
Real-Time SCADA output
Real-Time SCADA output
QSE
Realtime: ERCOT
Generator Instructions
Turbine
Wind Farm Description
Transmission/Interconnection
ERCOT
Balancing
Market
Realtime: ERCOT
Generator Instructions
Typical Operating Day
Data/Communication Flow
ERCOT-QSE-GEN COMMUNICATIONS DATA FLOW DIAGRAM
(SPLIT-METERING SITE)
Turbine
Wind Farm Description
Transmission/Interconnection
Typical Operating Day
Data/Communication Flow
Q&A
Slide 19
Thank You!