Increasing PV Hosting Capacity in Distribution Networks: Challenges and Opportunities. Dr Andreas T. Procopiou

Transcription

1 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Increasing PV Hosting Capacity in Distribution Networks: Challenges and Opportunities Dr Andreas T. Procopiou Research Fellow in Smart Grids andreas.procopiou@unimelb.edu.au The University of Melbourne Melbourne Institute of Energy Symposium 12 th December 2018

2 Solar PV in Australia Status, installations and cumulative capacity Challenges in PV-rich Distribution Networks Traditional and non-traditional mitigation approaches Understanding Solar PV impacts Smart PV Inverters Embedded Control Functions Increasing PV Hosting Capacity Residential Battery Energy Storage Systems Opportunity for advanced controllers (to manage technical issues) Conclusions Outline 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December

3 Number of Installations 62% Capacity (kwp) 123% Thousands Solar PV in Australia Installations Total Monthly Installations Average Installed Capacity Cumulative Installed Capacity GW Total Installed Capacity (GW) GW GW 2 million Installations 18GW by 2020 Solar PV Status, Australia: Australian PV Institute, [Online]. Available: Accessed on November A.T. Procopiou - The University of Melbourne MIE Symposium, December

4 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Challenges in PV-rich Distribution Networks Bulk Generation Transmission Distribution MV/LV Bulk supply point Voltage Max Min Distance PV Systems Not Generating

5 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Challenges in PV-rich Distribution Networks Bulk Generation Technical issues brought by high penetrations of solar PV significantly reduces hosting capacity of networks Transmission Distribution Congestion Voltage rise MV/LV Bulk supply point Traditional Solutions Network Reinforcement Voltage Max Min Distance PV Systems PV Systems Not Generating Generating

6 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Challenges in PV-rich Distribution Networks Solutions Bulk Generation Transmission Bigger Transformers Larger Cables MV/LV Traditional Solutions Network Reinforcement Bulk supply point Voltage Max Min Distance

7 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Challenges in PV-rich Distribution Networks Solutions Leveraging existing assets to manage technical issues and increase hosting capacity Bulk Generation Reinforcement Alternative Transmission Distribution MV/LV Generation Curtailment Reactive Power Absorption Bulk supply point Non-Traditional Solutions Smart Storage PV inverter and solar capabilities PV (reduce household exports) Max Min Distance

8 Understanding Solar PV Impacts Completed project Solar PV Penetration and HV-LV Network Impacts Project Real Victorian 22kV HV feeder Strong semi-urban 30km of conductors 79 distribution transformers Realistically Modelled LV Networks Australian Design Principles 175 LV feeders 4612 residential customers Stochastic Analyses - Monte Carlo Summer (December February) Varying locations and sizes (using regional PV stats) Smart meter demand and PV generation PV penetration increments of 10% (0-100%) % of customers with PV systems 1 1 A. Navarro, L.F. Ochoa, Probabilistic impact assessment of low carbon technologies in LV distribution systems, IEEE Trans. on Power Systems, May 2016 ( /TPWRS ) 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December

9 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Understanding Solar PV Impacts Stochastic Impact Analyses Completed project Solar PV Penetration and HV-LV Network Impacts Project LV Voltage Issues HV Conductors Congestion Default Volt-Watt settings (AS/NSZ :2015) not adequate to manage issues Hosting Capacity: 20% PV Penetration * Off-load taps at nominal position (3) and Volt-Watt function as per AS/NSZ :2015

10 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Source: Smart PV Inverters Embedded Controllability Source: Source: Embedded with power control functions Volt-Watt Volt-var Fixed PF Watt-PF Power Limit Embedded with communication interfaces

11 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Smart PV Inverters Embedded Control Functions 1. Active Power Limit Function 2. Volt-Watt Control Function Inverter Power Priority Watt Priority Limited Q 3. Volt-var Control Function 4. Watt-PF Control Function (a) Var Watt Priority

12 Max Watt Output (% of max output) % of available Vars Smart PV Inverters Control Function Examples Example settings used for demonstration purposes: Volt-Watt 100% 75% Volt-var 100% 50% 50% 0% % -50% 0% Voltage (p.u.) -100% Voltage (p.u.) A. Procopiou, Active Management of PV-Rich Low Voltage Networks, PhD Thesis, The Univ. of Manchester, 2017 ( A.T. Procopiou - The University of Melbourne MIE Symposium, December

13 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Smart PV Inverters Voltage Issues 60% PV Penetration on the Australian HV-LV Network BAU Volt-Watt Volt-var 34% 0% 34% 12% curtailment Volt-Watt control effective at the expense of energy curtailment Volt-var control ineffective due to limited Q when needed

14 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Smart PV Inverters Voltage Issues 60% PV Penetration on the Australian HV-LV Network BAU Volt-Watt Volt-var Volt-var (oversized or Var priority) 34% 0% 34% 0% 12% curtailment Volt-Watt control effective at the expense of energy curtailment Volt-var control ineffective due to limited Q when needed

15 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Smart PV Inverters Thermal Issues 60% Penetration on the Australian HV-LV Network BAU Volt-Watt Volt-var Volt-var (oversized) 5 Txs overloaded 0 Txs overloaded 76 Txs overloaded HIGHER UTILIZATION Curtailment from Volt-Watt eliminates Tx overloads Q from Volt-var creates more overloads

16 Reactive Power (% Available VARs) Power Factor 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Active Power (% Max Power) Smart PV Inverters Control Function Settings and Options 50% 40% 30% 20% 10% 0% % % -30% Volt-var California Hawaii IEEE-Cat A IEEE-Cat B AU/NZ Italy/Austria 120% 100% 80% 60% 40% 20% IEEE/Hawaii AU/NZ Austria Volt-Watt -40% -50% Voltage (p.u.) 0% Voltage (p.u.) Watt-PF AU/NZ 0.90 Italy/Austria/Germany % 20% 40% 60% 80% 100% Active Power (% Max Power) (a) Watt Priority (b) Var Priority (c) 10% Oversized with Watt Priority

17 Reactive Power (% Available VARs) Power Factor 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Active Power (% Max Power) 50% 40% 30% 20% 10% -30% -40% -50% California Hawaii IEEE-Cat A IEEE-Cat B AU/NZ Italy/Austria 60% 0% % Which is more adequate to mitigate 40% issues? -20% 1.02 Volt-var Smart PV Inverters Control Function Settings and Options What settings offer more 0% benefits? Voltage (p.u.) Voltage (p.u.) 120% 100% Extend of additional Hosting Capacity? 80% 20% IEEE/Hawaii AU/NZ Austria Volt-Watt Significant number of solution options Complex! Watt-PF AU/NZ 0.90 Italy/Austria/Germany % 20% 40% 60% 80% 100% Active Power (% Max Power) (a) Watt Priority (b) Var Priority (c) 10% Oversized with Watt Priority

18 On going project 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Selection of Network Increasing PV Hosting Capacity Hosting Capacity and Impact Solutions Assessment Tool Technical Issues Solution Methods for Increasing PV Hosting Capacity Project Specification of new PV (location, inverter) Real 22kV Feeder (200+ Dist. Tx, 500+ Customers) Hosting Capacity Limit Assessment Location of new PV System Solutions Assessment Primary Substation Distribution Substation Analysis Summary Used by Distribution Network Planners Next Level Hosting Capacity Limitation Analysis Summary

19 Source: Clean Energy Australia Report 2018 Number of Installations Thousands 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Residential Battery Energy Storage Systems Status in Australia Increasing interest of customers in Battery Energy Storage (BES) Store excess of PV generation and use it later Reduce grid imports; hence electricity bills 25 RESIDENTIAL ENERGY STORAGE SYSTEM INSTALLATIONS three-fold increase from Source: Clean Energy Australia Report 2018

20 Residential Battery Energy Storage Systems Off-the-shelf Operation and the Opportunity Off-the-shelf (OTS) BES operate for the sole benefit of the customer Do not provide benefits to the network 1 OTS Battery Controller BES systems have different control capabilities Opportunity to provide benefits to both network and customers Reduce reverse power flows, hence, network issues Alternative to costly network reinforcements Allow customers reduce electricity bills Household with 5kWp PV system, and 5kW/13.5kWh BES system 1 K. Petrou, L.F. Ochoa, A.T. Procopiou, J. Theunissen, J. Bridge, T. Langstaff, K. Lintern, "Limitations of residential storage in PV-rich distribution networks: An Australian case study" 2018 IEEE Power & Energy Society General Meeting 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December

21 Residential Battery Energy Storage Systems Residential Storage Controller for the Benefit of Customers and Networks 1 The Developed Battery Controller: Adapts charging power to the PV generation and Demand Reduces reverse power flow during peak generation periods Ensures available capacity by discharging overnight Always supports the demand, throughout the day Adapts to sudden changes in demand and generation No Communication Infrastructure Required Uses Local Measurements and Known Data Local Measurements: PV generation, Demand, SOC Known data: Clear-sky irradiance Reinforcement Alternative 1 A.T. Procopiou, K. Petrou, and L.F. Ochoa, "A controller for photovoltaic generation and energy storage system," Australia Patent , Available: A.T. Procopiou - The University of Melbourne MIE Symposium, December

22 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Voltages Residential Battery Energy Storage Systems Network Benefits PV Only Off-the-Shelf (OTS) With Proposed Battery Controller 18% Non-Compliant 10% Non-Compliant No Voltage Issues

23 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Asset Utilization Residential Battery Energy Storage Systems Network Benefits PV Only Off-the-Shelf (OTS) With Proposed Battery Controller With Proposed Battery Controller Lines and TXs Congested Lines and TXs Congested No Congestions

24 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Residential Battery Energy Storage Systems Customer Benefits Customer Grid Dependency - Year Analysis Grid Dependence Index % of demand imported from the grid 100% = Fully dependant to the grid With Proposed Battery Controller 0% = Energy Self-Sufficient

25 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Conclusions 1/2 DNSPs face challenges evaluating the growing penetrations of PV systems Locational and behavioral uncertainties of PV systems Simplified impact analyses are not adequate to cover uncertainties Advanced computational simulation models and techniques are required Detailed time-series analyses (three-phase, MV-LV, daily/seasonal demand/generation) Stochastic assessment (catering for uncertainties) Increasing PV hosting capacity: Leveraging existing assets (cost effective) Smart PV Inverters offer a wide range of solution options Volt-Watt is effective but in expense of curtailment Volt-var might be effective (if capability exists) but exacerbates asset utilization Complexity in identifying the most adequate combination of control and settings Advanced solution assessment tools required

26 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Conclusions 2/2 Increasing PV hosting capacity: Leveraging existing assets (cost effective) Residential BES Systems OTS control strategies (customer benefit oriented) do not increase PV hosting capacity Opportunity for new storage control strategies providing benefits to both: Network (management of technical issues, increasing HC) Customers (reduced grid imports, hence electricity bills) Trade-off between technical performance, customer impacts, practicality, and cost should always be taken into consideration

27 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Thank you! Acknowledgement Mr Kyriacos Petrou PhD Student Prof Luis F. Ochoa Professor in Power Systems

28 2018 A.T. Procopiou - The University of Melbourne MIE Symposium, December Increasing PV Hosting Capacity in Distribution Networks: Challenges and Opportunities Dr Andreas T. Procopiou Research Fellow in Smart Grids andreas.procopiou@unimelb.edu.au The University of Melbourne Melbourne Institute of Energy Symposium 12 th December 2018