Southern Company Interconnection Process. Dexter Lewis Research Engineer Research and Technology Management

Transcription

1 Southern Company Interconnection Process Dexter Lewis Research Engineer Research and Technology Management Southern Company

2 Outline Southern Company GPC Solar Interconnection Process Application requirements Distribution impact study Witness Testing

3 Southern Company

4 Southern Company 45,502 MW of generating capacity 41% natural gas, 37% coal, 16% nuclear, 6% hydro PV 60 MW with 115MW in application process Hydro 2,785 MW of generating capacity with 16MW of new capacity planned for next 5 years Biomass 128 MW Landfill Gas 3.2 MW landfill gas generator in Gulf Power Service Territory

5 Georgia Power Solar Georgia Public Service Commission adopted a motion that requires Georgia Power Company to bring online 260MW of solar capacity by 2015 and 265MW by 2017 (525MW total). 100MW of distributed small scale generation 425MW of utility scale solar Small generators ( 100 ) are eligible to sell their electricity under the Renewable & Non renewable Tariff (RNR 7) and the Solar Purchase Tariff (SP 1). Larger customers ( 80 ) may sell their electricity as a Qualifying Facility RNR 7 Company will pay avoided cost SP 1 Company will purchase at cents/kwh

6 GPC Number of Interconnection Requests 1 to 65 Inter

7 GPC kw Installed/Proposed/Anticipated 1 to 5000kW

8 GPC Average kw per Interconnection 1 to 1000kw/Inter

9 GPC Interconnection Process 10 Days +10 Days +10 Days Customer Submits Application Package GPC Processes & Reviews Application Package GPC and Customer Site Visits GPC Conducts Distribution System Studies +45 Days +45 Days +5 Days/+90 Days +10 Days/+30 Days Distributed GPC Conducts GPC Offers Customer Customer pays GPC Generation Interconnection Interconnection Interconnection Cost Interconnection Equipment Study Proposal Upfront Agreement Executed +10 Days GPC +Construction Installs GPC Interconnection Equipment +7 Days +3 Days GPC Conducts Facility Acceptance Testing GPC Authorizes Parallel Operation Facility Up to 155 Days + Construction

10 Customer Submits Application Package Facility One Line Electrical Diagram Facility Relay and Metering One Line Proof of site control in the form of a property tax bill, a lease agreement or other legally binding contract Application for Distributed Interconnection Required Technical Data

11 GPC Interconnection Process Customer Submits Application Package GPC Processes & Reviews Application Package GPC and Customer Site Visits GPC Conducts Distribution System Studies GPC Conducts Interconnection Equipment Study GPC Offers Customer Interconnection Proposal Distributed Generation Interconnection Agreement Executed Customer pays GPC Interconnection Cost Upfront GPC Installs GPC Interconnection Equipment GPC Conducts Facility Acceptance Testing GPC Authorizes Parallel Operation Facility

12 GPC Conducts Distribution Equipment Study 15 to 30 Business Days for GPC to conduct and complete DSS of Facilities less than or equal to 2MW after Facility is conceptually finalized by both GPC and Customer. 25 to 45 Business Days for GPC to complete DSS of Facilities 2MW to 10 MW after Facility design is conceptually finalized by both GPC and Customer.

13 Distribution Study Practices (Inverter Based) Less than 25kW Stamp and Go Procedure Inverter must be UL Standard 1741 Less than 1MW Stiffness Factor Procedure Engineering Guide for Integration of Distributed Storage and Generation EPRI ID: Stiffness Factor = Isc/Idsg

14 DPV Hosting Capacity Category Criteria Basis Flag Voltage Overvoltage Normal Voltage (ANSI C84.1) 1.05 Vpu Voltage Voltage Deviation Maximum difference in node voltage from no PV to full PV Voltage Unbalance Phase voltage deviation (ANSI C84.1) Loading Thermal Element loading 3% at primary 5% at secondary ½ band at regulators 3% 100% normal rating Protection Total Fault Total fault current contribution at Contribution each sectionalizing device 10% increase Protection Forward Flow Fault Contribution Forward flow fault current contribution at each sectionalizing device 10% increase Protection Sympathetic Breaker zero sequence current due to Breaker 150A an upstream fault Tripping Protection Reduction of Deviation in breaker fault current for Breaker Reach feeder faults 10% decrease Protection Breaker/Fuse Fault current increase at fuse relative Coordination to breaker current increase 100A increase Protection Anti-Islanding Minimum load at each sectionalizing device 50% Power Individual Individual harmonic voltage Quality Harmonics magnitude 3% Power Total Quality Harmonics Total harmonic voltage distortion 5% Control Regulator Increased duty > basecase+1 Control Capacitor Increased duty > basecase+1

15 CYME Analysis (Inverter Based) Voltage Violations 97% to 105% ANSI C84.1 Primary 3% Voltage Imbalance Overload Conditions Neutral current Total current less than 33% of trip setting Simulations Summer peak load without DG Summer peak load with DG Valley at 10:00AM 2:00PM without DG Valley at 10:00AM 2:00PM with DG Locked automation setting testing

16 CYME Analysis Assumptions Connected Transformer kva Load Allocation Model Use historical peak and valley substation loading information Locked customer loading for customers > 2MVA 60% constant impedance & 40% constant power loads Electronically Coupled Generator Kw, pf, Fault Contribution (140% of nameplate)

17 GPC Interconnection Process Customer Submits Application Package GPC Processes & Reviews Application Package GPC and Customer Site Visits GPC Conducts Distribution System Studies GPC Conducts Interconnection Equipment Study GPC Offers Customer Interconnection Proposal Distributed Generation Interconnection Agreement Executed Customer pays GPC Interconnection Cost Upfront GPC Installs GPC Interconnection Equipment GPC Conducts Facility Acceptance Testing GPC Authorizes Parallel Operation Facility

18 Facility Acceptance Testing Inverters >250kW Witness Test GPC Witness Test Personnel Required to record and witness test GPC Switching Personnel Required to operate the disconnecting of the high side fuse or switch Customer Setting Engineer Required to make adjustments to interconnection protection equipment Customer Test Engineer Required to perform secondary injection testing on interconnection protection equipment Customer Systems Operator Required to perform the customer switching of DC and AC systems Inverter Control Engineer Required to make adjustments to set points of the inverter if needed Customer Representative Required to sign witness test report upon completion

19 Facility Acceptance Testing Transient Overvoltage Test Single Phase Disconnect Test Shut down timing 2 sec disconnect, 5 min reconnect Inverter Control Mode Test Control power factor to predetermined set point 30 min

20 Site Testing Pictures

21 Normal Peak Voltage = 400 Volt = 1 PU Maximum Peak reached = 702 Volt = 1.76 PU PASS

22 Maximum Peak reached = 1100 Volt = 2.75 PU FAIL Normal Peak Voltage = 400 Volt = 1 PU

23 Maximum Peak reached = 1171 Volt = 2.93 PU Normal Peak Voltage = 400 Volt = 1 PU FAIL Transient Over Voltages last 24 ms

24 By Comparison, look at the same inverter installed at another location Notice the voltage peaks barely goes above 800 Volts or 2 PU PASS

25 By Comparison, look at the same inverter installed at another location Notice the voltage peaks barely goes above 800 Volts or 2 PU PASS

26 Single Phase Open Voltage Test Single phase opened here Single phase closed here Approximately 7 seconds of open phase

27 After settings on the inverter were changed The inverter takes 2 seconds before shutting down.

28 Next Steps Interconnection study with multiple connected DG Winter peak interconnection study? Need better estimate of time series impact Need CBA of constant PF inverter control Need to share learnings from utility experiences Southern Company needs to develop a DERMS Develop strategic plans at all business units for the integration of DER

29 Questions? Dexter Lewis Research Engineer Research and Technology Management Southern Company