8-2-Audrey_2022_PVPMC_RDE300i-2

Validation of In -Situ I -V Measurement Device for PV System Monitoring Applications Audrey Marquis 1 , Michael Gostein 1 , and Bruce H. King 2 1 Atonometrics, Inc., Austin, TX, USA; 2 Sandia National Laboratories, Albuquerque , NM, USA August 2022Acknowledgements This material is based upon work supported by the U . S .Department of Energy’s Solar Energy Technologies Office under Award Number DE-SC 0020012 . Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC,a wholly owned subsidiary of Honeywell International Inc . ,for the U . S .Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525 .IntroductionIV sweeps are useful for system monitoring Irradiance (including bifacial effective irradiance) Soiling Degradation TemperatureA clean and dirty module can be used to calculate soiling loss Clean Soiled Gostein , M. & Duster, T. & Thuman , C. PVSC 2015 Accurately Measuring PV Soiling Losses With Soiling Station Employing Module Power Measurements. Bifacial rear side irradiance is non -uniform Gostein , Michael & Ayala Pelaez , Silvana & Deline , Chris & Habte, Aron & Hansen, Clifford & Marion, Bill & Newmiller , Jeff & Sengupta, Manajit & Stein, Joshua & Suez, Itai . Measuring Irradiance for Bifacial PV Systems. PVSC 2021Bifacial reference modules measure total front + rear irradiance• Existing module IV sweep units require a standalone module alongside the array • Using power producing modules for measurement reduces engineering and racking costs RDE300i provides in -situ IV curves for any module in an arrayConnect RDE300i between target module and arrayModule String IV String RDE 300 i Normal operation During normal operation string current passes through RDE300iDuring full IV sweeps string current bypasses RDE300i Module I V String String IV RDE 300 i Bypass I sc P max V oc V mp I mp I-V SweepMini -sweep mode measures Pmax without disconnecting • Allows for more frequent measurements (10 seconds instead of 1 minute) • Measured module continuously produces power PmaxA clean and dirty module can be used to calculate soiling ratio Clean Soiled Leader Follower Clean Soiled Power & CommUse any module in your array Actual module = perfect matching Use a reference module to get total effective bifacial irradianceRDE300i is rated for the new generation of PV modules Up to 30 amps Up to 250 volts Up to 1500 watts String up to 1500 voltsValidating RDE300i at Sandia National LabsSandia provided a number of systems for testing • Used 5 different arrays – Monofacial and bifacial silicon modules – Various string level inverters from different manufacturers • Strings selected for testing have output power up to 4.8 kW Test beds at Sandia National Laboratories Photovoltaic Systems Evaluation Laboratory (PSEL) in Albuquerque, New Mexico Photo from Sandia National LaboratoriesRDE300i installed on a test rack at Sandia National LabsRDE300i measures Isc , Voc , Pmax, Vmp , Imp, Vout , and Ioutà Soiling à IrradianceTest ProtocolInverter operation must not be disturbed by RDE300i Testing goals: • Verify RDE300i functionality • Ensure no inverter faults • Ensure inverter follows M PP Tracking • Quantify any impact on inverter energy outputFunctionality Test: ensure no inverter fault events • Objective: Inverter functions are not interrupted – Data is monitored for irregularities indicating faults – Module power is correlated with the power measured at the inverter input – Quantify spikes to string Voc at the inverter • Objective: Measured Pmax correlates with system behavior – The module’s potential P max and actual operating point are compared