Hawai'i Island Planning and Operations With Changing Resource Mix

Transcription

1 1 Hawai'i Island Planning and Operations With Changing Resource Mix Lisa Dangelmaier Hawaii Electric Light Director, System Operations and Planning October 24, 2018

2 2 OVERVIEW

3 Hawai'i Electric Light System Overview 3 No interconnections Minimum load ~90MW Weekday Day peak ~145MW Weekday Day minimum ~115MW Evening Peak ~180MW Automatic Generation Control (AGC) used for frequency control and is based on economic dispatch. Renewable energy sources: wind, hydro, geothermal, and solar Large amount of distributed PV (approx. 90-MW) and increasing 1 MW 250kWH Battery Energy Storage System (BESS) Rely on Underfrequency Loadshed (UFLS) for operating reserves. No minimum requirement for spinning reserve.

4 Unique island challenges 4 o o o o o Supply/Demand Balancing much more difficult than larger systems o Small imbalance = large frequency change o Less stable o Generator trips often result in customer outages Isolation: Can t count on neighbor grids for generation support, need to install additional capacity for backup Small population density increase costs of service Must Plan for Unique Combination of Natural Events o Hurricanes and Winds o Tsunami o Earthquakes o Lava Flows o Fast-growing trees/vegetation Reliance on imported fuels

5 Renewable Energy Contribution 5 5

6 6 Hawaii Island Distributed Solar o DG-PV (over 90-MW) twice as large as any single generating plant. o Other generation provides all the balancing o No direct monitoring, no control

7 7 OPERATION WITH HIGH LEVELS OF VARIABLE AND DISTRIBUTED GEN

8 8 SENSE & MEASURE Meteorology for Operations and Planning

9 9 Funded Wind and Solar Forecasting Strategically sited remote sensors Using state-of-the-art forecasting models and remote sensors (SODAR, radiometer) ahead of wind facility to provide operators 30 min to 1 hr heads-up on potential ramp events. Industry Partners: US DOE ARRA funding; AWS TruePower, Atmospheric Research Technologies 9

10 Solar Instrumentation 10 Reference Met station at Kaneolani Elementary Feeder Monitoring Reference Solar Irradiance at Waipio Substation LM-1 at substation LM-2 with temperature sensor 10

11 11 Irradiance Monitors 11

12 Wind Power Forecasts 12

13 Solar Forecasts 13 Previously forecast/probability was based on a 30-minute time interval failing to detect ramps. Now 15 minute periods used. Lack of overnight updates has been problematic; new satellite will be used to improve.

14 14 Impact of DER on Net Demand Net Demand Change from PV

15 15 PV Impact on Ramping Fast net load ramps of MW Steep sustained ramp for morning and evening peak 15

16 Unit Commitment 16

17 Managing Variability and Uncertainty o Operators address uncertainty with online reserves o Uncertainty is reduced by making decisions as late as possible determined by unit start time (2-6 hours). o Real-time trends of wind speeds, irradiance, and forecast probability all used for decisions. o Use higher cost, more flexible units (simple cycle units, small diesels) for greater volatility and uncertainty o Combination of forecast probabilities and trends of actual output and irradiance. o To avoid possible high wind speed cut-out, wind plants cooperatively reduce output (curtail) if high winds are observed 17

18 Flexible Reserve Requirements Volatility (mw/min) and Variability Operator Adjusts Reserves Based on Trend Data 18

19 Wind Locational Differences 19 19

20 20 Distributed PV Ramps 2/10/2018 Normal operating range is Hz 20

21 Forecast Enhancements Improve solar feedback actuals with additional data points Solar 15-minute ramp probability (instead of 30) Night-time update with new satellite information with higher resolution and refresh rate to improve morning A future challenge: incorporate distributed energy storage impacts into peak forecast Improve gross demand forecast - major factor in net demand forecast error more temp. dependent Eruption impacts on solar and wind?

22 22 PLANNING CONSIDERATIONS

23 NET Demand Forecasting Challenges Net Demand forecast dependent on forecast DER production (and adoption) Behind the meter programs influence customer use Customers using more air conditioning Irradiance monitor data used to develop hourly profiles and regional characteristics Assumptions must be made on storage and EV Typical year and extremes identified

24 Resource Planning Variability in all time scales requires flexible resources to meet net demand and ramping needs under high and low variable production. Consider extremes for 100% renewable scenario. Need to consider uncertainty from forecast errors 24

25 25 25 Resource Acquisition Considerations Consider more than capacity factor! Load Correlation Resource Diversity Minute-to-minute variability Hourly production profile Seasonal variability Ability to forecast power production

26 26 Met Data Requirements identify meteorological requirements to include in interconnection and purchase power contracts 26

27 27 MEASURES TO IMPROVE RELIABILITY ON PATH TO 100% RE

28 Actions taken for Operability and Reliability for Existing and Increasing RE and DER DER interconnection requirements for bulk system Monitoring Control Ride-through capabilities based on local grid conditions Renewable generation that provides: Primary Frequency Response Dispatch under AGC w/ low load dispatch capability Fast ramp rate Flexibility (cycling, fast online time) Fast responding contingency reserve to mitigate legacy PV trip Dynamic under-frequency load-shed Improve forecasting models Demand Response 28

29 29 Distributed resource requirements Rule 14 H and IEEE MEASURES TO IMPROVE RELIABILITY ON PATH TO 100% RE

30 30 Ride-through Requirement: Frequency and Voltage for Island Systems Legacy PV tripping at 59.3

31 On small island, overfrequency 60.5 Hz can occur Aggregate loss of legacy PV largest contingency Driver for need tor large contingency storage 31

32 Transient Voltage and Frequency 32

33 Standards for DER Function Set Advanced Functions Capability UL 1741 Listing/ Certification UL 1741(SA) 2016 IEEE ?* Interconnection Standards IEEE IEEE 1547a IEEE State/ PUC/Utility Rules CA Rule 21 (Phases) 33 HI/HECO Rule 14H & UL SRDv1.1 All Adjustability in Ranges of Allowable Settings Monitoring & Control Scheduling Reactive Power & Voltage Support Bulk System Reliability & Frequency Support Other Advanced DER Functions Ramp Rate Control (P1) Communication Interface (P2) Disable Permit Service (Remote Shut-Off, Remote (P3) Disconnect/Reconnect) Limit Active Power (P3)!!! Monitor Key DER Data (P3) Scheduling Power Values and Models Set Active Power [ (P3) ] Constant Power Factor (P1) X Voltage-Reactive Power (Volt-Var) X (P1) Autonomously Adjustable Voltage Reference!!!!!! Active Power-Reactive Power (Watt-Var) X Constant Reactive Power Voltage-Active Power (Volt-Watt) X (P3) Dynamic Voltage Support during VRT [ (P3) ] Frequency Ride-Through (FRT) (P1) Rate-of-Change-of-Frequency Ride-Through!!!!!! Voltage Ride-Through (VRT) (P1) VRT of Consecutive Voltage Disturbances!!!!!! Voltage Phase Angle Jump Ride-Through!!!!!! Frequency-Watt X (P3) Anti-Islanding Detection and Trip (P1) Transient Overvoltage Remote Configurability (P2) Return to Service (Enter Service) (P3) (P1) Source: EPRI

34 Frequency ROCOF and phase angle ride-through: Recorded PMU Data 34 10/22/2018

35 Load (MW) Control Needed for Oversupply, 35 Reserves, and Restoration Load curve created by extrapolating PV on a high PV / low load day to connected PV Dsptch Rng Wind 120 Hydro Add CC Unit 100 Regulating Range Keahole Wind Curtail Keahole 1CTCC Minimum Contingency Reserves Geothermal Contractual Minimum Keahole 2nd Unit & HEP Cntgcy Rsv PGV Steam Load Est Ld w/o PV 0 Steam Unit minimums 0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00 Sunday, March 18, /12/

36 Reserve Constraint 36 4/12/

37 37 Fast-responding storage MEASURES TO IMPROVE RELIABILITY ON PATH TO 100% RE

38 Battery Energy Storage System (BESS) 38 Finalizing report on large (15-mw or larger) BESS due (contingency reserve for aggregate PV loss at legacy voltage/frequency) Experience with 1 MW 250kWHr Lithium Titanate Chemistry Fast-Response Energy Storage System. Radially connected via a 34.5kV line. Can operate in wind plant smoothing or primary frequency response

39 Storage (BESS) 39 Even though small, the BESS reduces the frequency variability due to wind output Must be careful to avoid charging during upsets Frequency smoothed by BESS RESPONSE

40 40 Dynamic and Adaptive Underfrequency Load Shed ACTIONS TO IMPROVE RELIABILITY ON PATH TO 100% RE

41 Dynamic Underfrequency Loadshed (DUFLS) 41 Adaptive / dynamic scheme that uses the Energy Management System (EMS) to automatically assign UFLS Stages (trip settings) to the distribution circuits based on System load and other circuit information every 15-minutes. Study was performed in 2015 that identified the need for DUFLS to avoid over shedding of customer loads that could affect distributed PV. System went live on December 12, 2017.

42 Adaptive UFLS Design 42 Stage 1 and stage 2 should sum to 15% of the system net load which is the maximum allowed load shedding for N-1 unit trips. Stage 1 through stage 4 should sum to 40% of the system net load which is the maximum allowed load shedding for N-1-1 unit contingencies Adjust the stages of UFLS to reflect a percentage of net system load on each stage. The recommended percentages are: Df/dt 15%, 0.5 Hz/sec, 9 cycle relay plus breaker time (Still in verifying final setting) Stage 1 5%, 59.1 Hz, 8 cycle relay plus breaker time Stage 2 10%, 58.8 Hz, 8 cycle relay plus breaker time Stage 3 10%, 58.5 Hz, 8 cycle relay plus breaker time Stage 4 15%, 58.2 Hz, 8 cycle relay plus breaker time Stage 5 10%, 57.9 Hz, 8 cycle relay plus breaker time Stage 6 20%, 57.6 Hz, 8 cycle relay plus breaker time Retain most recent UFLS settings in the event of SCADA/EMS communication failure until communications are restored.

43 Scope of Work 43 Relay upgrade (SEL451 of 651R) RTAC installation EMS custom application to assign circuits to UFLS Blocks Monitor events to determine effectiveness of new UFLS scheme. Implemented late 2017.

44 44 System Performance after 2018 Eruption Impacts. RELIABILITY AND RESIILIENCY

45 Unique island challenges 45 Must Plan for Unique Combination of Natural Events o Hurricanes and Winds o Tsunami o Earthquakes o Lava Flows o Large, Fast-growing Trees Coordinated Emergency Response o State, County

46 Pre-Eruption Power Supply Base FIRM (24-hr) POWER Units PLANTS - Hill 5 & 6 Steam Units - Keahole Shipman, 1CT in Kanoelehua, combine cycle Puna, (CC) - PGV Waimea, (Geothermal) Keahole Intermediate Units Independent Power - Keahole 2 Producers: nd unit in CC - HEP 1 st and 2 nd Puna in CC Geothermal Peaking/Emergency Venture, Hamakua Units Energy - Kanoelehua Partners CT-1 - Keahole CT-2 - Puna CT-3 - Puna Steam Unit - 12-Small Diesel Generators Puueo Hydro, Waiau Hydro As-Available Must-Take - HRD Independent Windfarm (10.5 Power MW) - Pakini Producers: Nui Windfarm Wailuku (20.5 River MW) - Wailuku Hydro, River Tawhiri Hydro Wind, (12 MW) Hawi - Puueo Hydro (3.1 MW) Renewable Development Wind NON-FIRM POWER PLANTS KEAHOLE NORTH KOHALA NORTH KONA SOUTH KONA HAWI RENEWABLE DEVELOPMENT WAIMEA PLANT SOUTH KOHALA KA`U TAWHIRI WIND FARM HAMAKUA ENERGY PARTNERS NORTH HILO WAILUKU RIVER HYDRO SOUTH HILO WAIAU & PUUEO HYDROS PUNA HILL PLANT PGV 46 PUNA PLANT - Waiau Hydro (1.1 MW) Firm Generation (capacity): East HI: 70% West HI: 30% Load: 50% / 50%

47 47

48 Post-Eruption Power Supply Base (24-hr) Units - FIRM Hill 5 & POWER 6 Steam Units PLANTS - Keahole 1CT in combine cycle (CC) - PGV Shipman, (Geothermal) Kanoelehua, Puna, Intermediate Waimea, Keahole Units - Keahole Independent 2 unit Power in CC - HEP Producers: 1 st and 2 nd Puna in CC Geothermal Peaking/Emergency Units Venture, Hamakua Energy - Kanoelehua CT-1 - Keahole Partners CT-2 - Puna CT-3 - Puna Steam Unit - 12-Small Diesel Generators As-Available Puueo Hydro, Must-Take Waiau Hydro - HRD Windfarm (10.5 MW) - Pakini Independent Nui Windfarm Power (20.5 MW) - Wailuku Producers: River Wailuku Hydro (12 River MW) - Puueo Hydro, Hydro Tawhiri (3.1 MW) Wind, Hawi - Waiau Renewable Hydro (1.1 Development MW) Wind NON-FIRM POWER PLANTS KEAHOLE NORTH KOHALA NORTH KONA SOUTH KONA HAWI RENEWABLE DEVELOPMENT WAIMEA PLANT SOUTH KOHALA KA`U TAWHIRI WIND FARM HAMAKUA ENERGY PARTNERS NORTH HILO WAILUKU RIVER HYDRO SOUTH HILO WAIAU & PUUEO HYDROS PUNA Firm Generation: East HI: 39% West HI: 61% Load: 50% / 50% HILL PLANT PGV 48 PUNA PLANT

49 Geothermal Provided over 25% Total Energy 49 49

50 West to East Power Flow (MW) Generation % 90% 80% 70% 60% 50% 40% West East 30% 20% 10% % 4/1 5/1 5/31 Prior to eruption, power flowed from East to West. West Hawaii subject to low-voltage and even voltage collapse /1-10 5/1 5/31 MW Following PGV being impacted by lava, power flowed from West to East. Difficulty with low voltages in East Hawaii.

51 Frequency (Hz) Dynamic Underfrequency Loadshed (DUFLS) - Events 51 Since go live, there has been 5 UFLS events. All events occurred following the loss of PGV 1 st event occurred on June 14, 2018 after months of anticipation. A steam plant tripped offline, and the 2 nd kicker stage operated. It had a 59.5 Hz trip setting with 20-second time delay Freq Time (mm:ss.s)

52 Dynamic Underfrequency Loadshed (DUFLS) - Events 52 2 nd event was due to the loss of a combustion turbine that resulted in the 1 st stage of UFLS to operate. 3 rd, 4 th and 5 th events resulted in multiple stages of UFLS to operate, but in each case System stabilized. The 3 rd event (loss of the south point wind farm) is interesting to examine because there were several occurrences over the past few years that illustrates how differently the System behaves under different configurations.

53 Identified Worse Case UFLS Event 53 It was previously identified in studies that a trip of the South Point Windfarm while Hill 6 was offline was the worse single contingency generation event.

54 Frequency (Hz) Confirming Model Results On May 11, 2017 (last year), South Point Windfarm tripped offline while producing 19.8 MW. UFLS Block 1 and the kicker block operated. Largest Overall ROCOF was observed at Hz/sec /11/ Cycles (1/60 Second)

55 Frequency (Hz) Confirming Model Results By comparison, another windfarm trip occurred on August 9, 2017 while producing 19.9 MW and Hill 6 was online. There was no UFLS. Overall ROCOF was Hz/Sec /11/2017 8/9/ Cycles (1/60 Second)

56 Frequency (Hz) Trip with different Base Case Situation On August 9, 2018, the windfarm tripped again while producing only 8.4 MW with PGV and Hill 5 offline, and a transmission line out of service. UFLS Stages 1 and 2 operated. Overall ROCOF was Hz/Sec /11/2017 8/9/2017 8/9/ Details of 8/9/2018 event still being investigated Cycles (1/60 Second)

57 Summary Hawaii Island power grid has significantly changed since loss of the geothermal plant and Pohoiki Substation by lava. Power flow now is primarily West to East Voltages lowest in East Hawaii Rates of Change of Frequency exceeds historical Greater UFLS for same events Reactive power requirements require uneconomic dispatch Previously deemed routine work now requires additional analysis. Additional studies are needed to identify System risks, reactive power requirements, and solutions which may include precontingencies dispatch requirements. Operations no longer can rely on historical grid behavior to understand impacts of contingencies and outages. Dynamic UFLS Scheme appears to be working well, will use reviews of operational data and performance to make any refinements and adjustments. 57

58 MAHALO 58