BPA Wind Voltage Control Requirements

Transcription

1 BPA Wind Voltage Control Requirements PJM Conference Dmitry Kosterev Bonneville Power Administration

2 Many of BPA Paths are Stability-Limited Cross-Cascades North Montana - Northwest Cross-Cascades South Wind Pacific HVDC Intertie California Oregon Intertie Slide 2

3 Pre-2007 Projects Wind generation amount was below 500 MW Wind power plants were not required to contribute to voltage control Required to operate at unity power factor Size switched reactive to compensate for reactive power losses Many operational challenges were observed Slide 3

4 Customer Impacts Voltage versus Power for a Wind Farm (Actual Operating Data) Voltage Voltage (Per Unit) 1 Wind Farm Voltage Customer Voltage Power Power (Per Unit of Full Output) Excessive LTC operations Slide 4

5 Voltage (per unit) Power (MW) MW WPP Connected to 115-kV Voltages Time (min) Wind Total Power kV bus 34.5-kV bus Time (min) Wind Total Reactive Power 0 These are actual recordings Project did not have dynamic reactive capabilities Several oscillatory events were observed with all lines in service The power output was curtailed STATCOM with voltage controller was installed Reactive (MVAR) Time (min) Slide 5

6 Wind power ramp Voltage (kv) Voltage Early plants do not have STATCOMs and use only shunt caps Power (MW) Reactive (MVAR) Time (min) Active Power Time (min) Reactive Power Time (min) Operate mainly in power factor mode As POI voltage declines WPP draws larger amount of reactive power Slide 6

7 Wind Ramp PV-Curve for same wind ramp 243 PV Plot - Voltage versus Wind Total 242 Voltage (kv) The edge All lines in service Power (MW) Slide 7

8 Modeling (Lesson Learned) Wind Power Plant models were unable to predict the observed the stability issues ahead of time Model tuning was required to match in principle the disturbance recordings with reality Static powerflow snapshots were often found inadequate, there was a need for a time-sequence simulation of power ramps

9 Modeling BPA made a major effort on improving powerflow models for WPPs based on WECC Guidelines for WPP Powerflow Modeling BPA is participating in DOE-NREL-UWIG project on dynamic model validation BPA requires all new projects connecting at 230-kV level to install Phasor Measurement Units (PMUs) / extended DFRs at POIs BPA is working with the WPP owners on retrofitting the existing WPPs with PMUs Slide 9

10 2006 Study BPA conducted a large-scale study to determine the impact of 3,000 MW of wind on system macro stability The study concluded that the wind power plants need to provide voltage Major voltage stability, transient stability, and undampened oscillations were observed should wind operate in power factor mode, resulting in intertie derating Slide 10

11 Voltage Control Requirements BPA requires wind power plants to provide voltage control and reactive power to support the grid just like other large generation projects How much reactive is needed: Dynamic reactive sized to provide continuous +/ power factor at 34.5-kV bus Switched shunts to compensate for reactive power losses between WTGs and Point Of Interconnection, high switching duty Slide 11

12 100 MW Type 2 with STATCOM W 1.0 pf Three 10 MVAR switched shunts capacitors to compensate for steady-state reactive losses, high switching duty (can be on BPA high side) +/- 16 MVAR STATCOM +/-32 MVAR 2-second overload capability W Slide 12

13 100 MW Type 3 or 4 Wind Generator Example W W Two 9 MVAR switched shunts capacitors to compensate for steady-state reactive losses, high switching duty (can be on BPA HV bus for several plants) +/ pf (+/- 33 MVAR) continuously controllable Reactive power deliverability Slide 13

14 Voltage Control Requirements How to control reactive resources: Operate in continuous (no dead-band!) voltage control mode, control POI voltage to BPA schedule with reactive droop Switching shunts to maximize the availability of dynamic capabilities at the plant Slide 14

15 POI Voltage Voltage Control Mode High Side Voltage Control Power Factor / VAR Control HSVC with a Droop (5.8% on plant MW base) Power Plant POI Reactive Power 15 Slide 15

16 Observed Challenges Reactive power deliverability Collector system voltage raise prevents WPP from delivering VARs to POI Shunt capacitor availability Long discharge time Reactive power coordination among several WPPs in the same wind hub Slide 16

17 250.0 Jones Canyon 230-kV Voltage B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Leaning Juniper #2B V-Q kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : Leaning Juniper #2B MW MW kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ :00 Leaning Juniper #2B MVAR MVAR /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : M VAR Slide 17

18 250.0 Jones Canyon 230-kV Voltage B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Leaning Juniper #1 V-Q kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : Leaning Juniper #1 MW MW kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ :00 Leaning Juniper #1 MVAR MVAR /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : M VAR Slide 18

19 250.0 Jones Canyon 230-kV Voltage B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Rattle Snake V-Q kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : Rattle Snake MW MW 60.0 kv /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ :00 Rattle Snake MVAR MVAR /27/ :00 12/28/2011 0:45 12/28/2011 4:30 12/28/2011 8:15 12/28/ : M VAR Slide 19

20 Wind Hub Generation Situational Awareness Slide 20

21 BPA Activities in Progress Voltage control Working with WPP operators on implementing a droop control Coordination of reactive resources in a wind hub Modeling and Monitoring Projects to install and integrate WPP PMUs DOE-UWIG Wind Modeling Project Situational Awareness SCADA alarming, PI applications for voltage control monitoring Dynamic transfers WECC VGS Planning Guideline Slide 21