10 ai impacts&settings_pvss2016_rylander_
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This document summarizes a project analyzing advanced inverter settings to increase solar PV hosting capacity on distribution grids without requiring system upgrades. The project team developed simple to complex methods to derive advanced inverter power factor, volt-var, and volt-watt settings. These settings were tested on models of 5 utility feeders that varied in peak load and solar hosting capacity. Power factor control Method 3 and volt-var control Method 3 increased hosting capacity the most while effectively using reactive power resources. Volt-var Method 1 had the least complex settings but still made good use of reactive power. The conclusions recommend using these advanced inverter functions to allow more solar without infrastructure upgrades.
10 ai impacts&settings_pvss2016_rylander_
- 1. © 2016 Electric Power Research Institute, Inc. All rights reserved. Matthew Rylander, EPRI Jeff Smith, EPRI Robert Broderick, SNL Barry Mather, NREL May 10, 2016 Advanced Inverter Impacts and Methods to Determine Recommended Settings Analysis to Inform CA Grid Integration Rules for PV
- 2. 2 © 2016 Electric Power Research Institute, Inc. All rights reserved. Outline California Solar Initiative project overview Explain simple methods to derive settings Illustrate distribution feeder response to settings Today’s Key Takeaway: Simple methods to derive settings
- 3. 3 © 2016 Electric Power Research Institute, Inc. All rights reserved. Project Overview Project Goal Determine advanced inverter settings to accommodate more PV without system upgrades – Power factor, volt-var, volt-watt – Settings and/or methods to determine settings .3 1.0 1.9 2.7 2.5 3.2 4.6 .7 .9 1.2 1.8 2.6 3.6 .3 .3 .5 .8 1.3 1.8 2.4 .9 1.9 3.3 4.7 5.6 7.6 10.6 2010 2011 2012 2013 2014 2015 2016 Utility Commercial Residential Industry Challenge Landscape is changing – Distributed resources New challenges for utilities – Accommodate more PV – Use Advanced Inverters Impact Below Threshold Impact Depends Impact Above Threshold Setting 3 Setting 2 Setting 1 Unity Power Factor
- 4. 4 © 2016 Electric Power Research Institute, Inc. All rights reserved. Approach to Derive/Test Recommended Settings/Methods Select Feeders Develop Methods to Derive Settings Apply Methods and Determine Feeder Impact Final Deliverable Summer 2016
- 5. 5 © 2016 Electric Power Research Institute, Inc. All rights reserved. Select Feeders
- 6. 6 © 2016 Electric Power Research Institute, Inc. All rights reserved. Feeders Selected from Previous Analysis* Utility 1 Utility 2 Utility 3 Impact Below Threshold Impact Depends Impact Above Threshold CPUC-CSI3 *Alternatives to the 15% Rule: Final Project Summary. EPRI, Palo Alto, CA: 2015. 3002006594.
- 7. 7 © 2016 Electric Power Research Institute, Inc. All rights reserved. Selected Feeder Details Criteria for feeder selection Utility Feeder characteristics Hosting capacity Feeder Name Peak Load (MW) Farthest 3-phase Bus (km) PV Hosting Capacity Nominal Voltage 683 3.6 17.9 Low 12 kV 631 3.4 11.7 Moderate 12 kV 888 2.2 2.8 Low 4 kV 2885 9.2 11.9 Low 12 kV 281 16.7 10.3 High 21 kV 2921 6.4 15.5 Moderate 12 kV 420 5.0 4.7 High 12 kV
- 8. 8 © 2016 Electric Power Research Institute, Inc. All rights reserved. Develop Methods to Derive Settings
- 9. 9 © 2016 Electric Power Research Institute, Inc. All rights reserved. Level Complexity Power Factor Volt-var Volt-watt 0 None Unity Power Factor Disabled, Unity Power Factor Disabled, Unity Power Factor 1 Low Based on Feeder X/R Ratio Generic Setting Generic Setting 2 Medium Based on Feeder Model and PV Location Based on Feeder Model and PV Location Not Applied 3 High Based on Feeder Model and PV Location Based on Feeder Model, PV Location, and Service Transformer Impedance Not Applied Methods to Derive Settings
- 10. 10 © 2016 Electric Power Research Institute, Inc. All rights reserved. Power Factor Control Level 1 settings: – Most simple method required to determine settings – Setting is feeder specific – Setting is based on the Median X/R ratio on the feeder Level Method Data Requirements Power Factor Setting 1 Median X/R Ratio of all 3- phase MV nodes to determine power factor Primary node X/R ratios on feeder, number of phases at each node Single Setting on each feeder 𝑃𝑃𝑃𝑃𝑃 𝑓𝑓𝑓𝑓𝑓𝑓 ≅ 𝑋 𝑅� 𝑚𝑒𝑒𝑒𝑒𝑒 𝑋 𝑅� 𝑚𝑚𝑑𝑑𝑑𝑑 2 + 1
- 11. 11 © 2016 Electric Power Research Institute, Inc. All rights reserved. Volt-var Control Level 1 settings: – Wide bandwidth (does nothing when within 2% from nominal) – Maximum reactive power output equivalent to 90% power factor when real power is at full output (assumed that the inverter is 10% larger than the PV system rating)
- 12. 12 © 2016 Electric Power Research Institute, Inc. All rights reserved. Volt-watt Control Level 1 settings: – Delayed control (does not curtail power when voltage is within ANSI limits) – Reactive power control functions should be utilized before the inverter voltage reaches the ANSI limit – Active power curtailed to Zero at 1.1pu voltage
- 13. 13 © 2016 Electric Power Research Institute, Inc. All rights reserved. Apply Methods and Determine Feeder Response
- 14. 14 © 2016 Electric Power Research Institute, Inc. All rights reserved. Feeder Response Feeder response based on same hosting capacity analysis used in CPUC-CSI3 feeder analysis – The thousands of stochastic PV scenarios were converted from unity power factor for each of the settings/methods derived PV scenario correlated to Median hosting capacity used to compare settings/methods – Quantified by advanced inverter setting result minus result from unity power factor Median Hosting Capacity: Defined when 50% of the analyzed scenarios have a violation. L1: Simple L2: Moderate L3: Complex
- 15. 16 © 2016 Electric Power Research Institute, Inc. All rights reserved. Quantifying Overall Impact from the Method/Setting Overall feeder impact is quantified by: – Hosting Capacity – Reactive Power – Losses (assumed negligible) Hosting Capacity Reactive Power Impact Ratio
- 16. 17 © 2016 Electric Power Research Institute, Inc. All rights reserved. Comparison of Overall Impact from Power Factor and Volt-var Power factor Level 1 and Level 2 have the least effective use of reactive power Level 3 power factor and Level 3 volt-var provided similar increase in hosting capacity and also demand of reactive power, thus their overall ratio is comparable Volt-var Level 1 had low improvement in hosting capacity yet the control settings has some of the most effective use of reactive power Volt-varPowerFactor
- 17. 18 © 2016 Electric Power Research Institute, Inc. All rights reserved. Conclusions Power Factor Method Level 3 generally provides the most benefit with regards to hosting capacity while effectively using reactive power to do so Volt-var Method Level 1 is the least complex and has one of the most effective uses of reactive power Volt-watt Method Level 1 should be used in conjunction with power factor or volt-watt control while these reactive power control functions should prevent the unnecessary curtailment of active power when operated first
- 18. 19 © 2016 Electric Power Research Institute, Inc. All rights reserved. Together…Shaping the Future of Electricity Robert Broderick rbroder@sandia.gov 505.844.8161 Jeff Smith jsmith@epri.com 865.218.8069 Matthew Rylander mrylander@epri.com 512.351.9938 Barry Mather Barry.Mather@nrel.gov 303.275.4378
- 19. 20 © 2016 Electric Power Research Institute, Inc. All rights reserved. References Public Link to Reports Online CSI:RD&D. (2015). Analysis to Inform California Grid Integration Rules for PV. Available: http://calsolarresearch.ca.gov/funded-projects/110-analysis-to- inform-california-grid-integration-rules-for-pv Alternatives to the 15% Rule: Modeling and Hosting Capacity Analysis of 16 Feeders. EPRI, Palo Alto, CA: 2015. 3002005812. Alternatives to the 15% Rule: Final Project Summary. EPRI, Palo Alto, CA: 2015. 3002006594.