Modeling Distribution System Impacts of Solar Variability and Interconnection Location

Transcription

1 Modeling Distribution System Impacts of Solar Variability and Interconnection Location Photos placed in horizontal position with even amount of white space between photos and header Matthew J. Reno 1,2, Abraham Ellis 1, Jimmy Quiroz 1, and Santiago Grijalva 2 1 Sandia National Laboratories 2 Georgia Institute of Technology Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy s National Nuclear Security Administration under contract DE-AC04-94AL85000.

2 Background There are an increasing number of PV interconnection study requests on the distribution system Initially, first-level screening tools and rules of thumb are used Some situations require more detailed study: High penetrations of solar Highly variable locations Multiple PV scenarios on the same feeder Quick, easy-to-use methods and tools are needed for detailed analysis

3 Challenges of Interconnection Studies Time-varying nature of distribution system load and solar output Large amounts of solar data and load data are not always available Accurate solar data and modeling are key Simulation of multiple PV deployment scenarios Hundreds of scenarios to analyze Different amounts of PV PV density (centralized, distributed) Variations in PV connection location Load level: peak, minimum, max solar penetration period Analyses: voltage, flicker, etc

4 Proposed Analysis Tool Key Features Developed Model solar power easily and accurately Visualize models with graphical user interfaces Integrate GIS functionality through Google Maps Identify critical times of year for analysis Perform timeseries and steady-state simulations Model impacts of solar variability Analyze the locational value of PV placement on the feeder

5 Proposed Analysis Tool Key Features Developed Model solar power easily and accurately Visualize models with graphical user interfaces Integrate GIS functionality through Google Maps Identify critical times of year for analysis Perform timeseries and steady-state simulations Model impacts of solar variability Analyze the locational value of PV placement on the feeder

6 Setting up the PV scenarios

7 Varying PV Scenarios Model both central and distributed PV plants Establish interconnection locations to the distribution feeder Use combinations of types at various locations

8 Simulating PV Plants - WVM PV plant output profiles are a function of the variability smoothing due to geographic size and diversity Wavelet variability model (WVM) applies a different amount of smoothing at each timescale using a scaling coefficient A value WVM has been shown to simulate power output well (Copper Mountain and Ota City PV power plants) WVM Inputs PV Plant Footprint Density of PV Point Sensor Timeseries Location/day dependent A coefficient variability reduction at each wavelet timescale WVM Outputs Plant Average Irradiance irradiance to power model Plant Power Output M. Lave, J. Kleissl, and J. Stein, "A Wavelet-based Variability Model (WVM) for Solar PV Powerplants, submitted to IEEE Transactions on Sustainable Energy Special Issue on Solar Energy,

9 Modeling the Distribution System Distribution system model and power flow are solved in OpenDSS OpenDSS is run from MATLAB through a COM interface to Integrate solar data features Facilitate post-simulation analysis Loop through scenarios

10 Identifying Critical Periods for Analysis

11 Solar Penetration

12 Types of Analyses and Displays Voltage contour of the feeder for spatial analysis Voltage profile of the feeder with the distance to the substation Max/min feeder voltages throughout the day Deviation in feeder voltages Net feeder load Net feeder power factor Various animations of voltages and power flows

13 Voltage Contour Without Solar Central Plant Basecase Without Solar Central Plant Middle of the Feeder Distributed Solar Distributed Central Plant End of the Feeder x 10 7 Toquerville PV Central 3 5Plant 7500 Substation PV PCC x

14 Maximum and Minimum Voltages

15 Bus Voltage (pu) Bus Voltage (V) Bus Voltage Bus (pu) Voltage (V) Bus Voltage Bus (pu) Voltage (V) Feeder Profile Analysis Terminal (June 7, 12:00 PM) PhaseA PV PhaseB PV PhaseC PV PhaseA PhaseB PhaseC Toquerville (May 23, 12:00 PM) PhaseA PV PhaseB PV PhaseC PV PhaseA PhaseB PhaseC Distance (km) Delta (June 13, 12:45 PM) Distance (km) PhaseA PV PhaseB PV PhaseC PV PhaseA PhaseB PhaseC Distance (km)

16 Bus Voltage (pu) Bus Voltage (pu) Bus Voltage (pu) Feeder Profile Analysis Terminal Basecase No PV PhaseA PhaseB PhaseC Terminal 1500 PV Central Distance (m) PhaseA MW PhaseB Central PV PhaseC PV PCC Terminal 1500PV Distributed Distance (m) PhaseA MW PhaseB Distributed PV PhaseC PV PCC Distance (m)

17 LTC Tap LTC Tap LTC Tap LTC Operations LTC Taps: 23 Changes during Week No PV 23 tap changes LTC Taps: 43 Changes Hour during Week MW PV 43 tap changes Hour LTC Taps: 85 Changes during Week MW PV 85 tap changes Hour

18 Location Value of Solar The placement and interconnection location of the solar can provide added benefits or difficulties Calculating the Power Transfer Distribution Factors (PTDFs) Decrease in line losses due to a transfer of 10 kw power generation from the utility at the substation (upper left) to potential PV buses locations. 18

19 Location Value of Solar The placement and interconnection location of the solar can provide added benefits or difficulties Calculating the Power Transfer Distribution Factors (PTDFs) Decrease in line losses due to a transfer of 10 kw power generation from the utility at the substation (upper left) to potential PV buses locations. 19

20 Conclusions Simulation software for integration studies Integrates the simulation power of OpenDSS with the visual user interface of MATLAB Contouring and Google Maps are used to visualize the spatial effect of solar Timeseries simulations show the time-varying nature of solar energy and load A simple method is proposed for determining value of the location of a solar array on a feeder to regulate voltage or decrease losses 20