Southern Company Interconnection Process Dexter Lewis Research - - PowerPoint PPT Presentation

Southern Company Interconnection Process

Dexter Lewis Research Engineer Research and Technology Management Southern Company

Outline

• Southern Company
• GPC Solar
• Interconnection Process

–Application requirements –Distribution impact study –Witness Testing

Southern Company

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

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 17.00 cents/kWh

GPC Number of Interconnection Requests

1 to 65 Inter

GPC kW Installed/Proposed/Anticipated

1 to 5000kW

GPC Average kW per Interconnection

1 to 1000kw/Inter

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 10 Days +10 Days +10 Days +45 Days +45 Days +5 Days/+90 Days +10 Days/+30 Days +10 Days +Construction +7 Days +3 Days Up to 155 Days + Construction

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

• r other legally binding contract
• Application for Distributed

Interconnection

• Required Technical Data

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

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.

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: 1024354 – Stiffness Factor = Isc/Idsg

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 ≥ 3% at primary ≥ 5% at secondary ≥ ½ band at regulators Voltage Unbalance Phase voltage deviation (ANSI C84.1) ≥ 3% Loading Thermal Element loading ≥ 100% normal rating Protection Total Fault Contribution Total fault current contribution at each sectionalizing device ≥ 10% increase Protection Forward Flow Fault Contribution Forward flow fault current contribution at each sectionalizing device ≥ 10% increase Protection Sympathetic Breaker Tripping Breaker zero sequence current due to an upstream fault ≥ 150A Protection Reduction of Breaker Reach Deviation in breaker fault current for feeder faults ≥ 10% decrease Protection Breaker/Fuse Coordination Fault current increase at fuse relative to breaker current increase ≥ 100A increase Protection Anti-Islanding Minimum load at each sectionalizing device ≥ 50% Power Quality Individual Harmonics Individual harmonic voltage magnitude ≥ 3% Power Quality Total Harmonics Total harmonic voltage distortion ≥ 5% Control Regulator Increased duty > basecase+1 Control Capacitor Increased duty > basecase+1

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

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)

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

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

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

Site Testing Pictures

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

PASS

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

FAIL

Normal Peak Voltage = 400 Volt = 1 PU Maximum Peak reached = 1171 Volt = 2.93 PU

Transient Over Voltages last 24 ms

FAIL

Notice the voltage peaks barely goes above 800 Volts or 2 PU

PASS By Comparison, look at the same inverter installed at another location

Notice the voltage peaks barely goes above 800 Volts or 2 PU

PASS By Comparison, look at the same inverter installed at another location

Single phase

• pened

here Single phase closed here

Approximately 7 seconds of open phase

Single Phase Open Voltage Test

After settings on the inverter were changed

The inverter takes 2 seconds before shutting down.

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

Questions?

Dexter Lewis Research Engineer Research and Technology Management Southern Company