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Comparison of Ideal Transformer Method and Damping Impedance Method for PV Power-Hardware-In-The-Loop Experiments

Conference Record of the IEEE Photovoltaic Specialists Conference

Summers, Adam; Hernandez Alvidrez, Javier H.; Darbali-Zamora, Rachid; Reno, Matthew J.; Johnson, Jay B.; Gurule, Nicholas S.

The Ideal Transformer Method (ITM) and the Damping Impedance Method (DIM) are the most widely used techniques for connecting power equipment to a Power-Hardware-in-the-Loop (PHIL) real-time simulation. Both methods have been studied for their stability and accuracy in PHIL simulations, but neither have been analyzed when the hardware is providing grid-support services with volt-var, frequency-watt, and fixed power factor functions. In this work, we experimentally validate the two methods of connecting a physical PV inverter to a PHIL system and evaluate them for dynamic stability and accuracy when operating with grid-support functions. It was found that the DIM Low Pass Lead Filter (LPF LD) method was the best under unity and negative power factor conditions, but the ITM LPF LD method was preferred under positive power factor conditions.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Identifying Common Errors in Distribution System Models

Conference Record of the IEEE Photovoltaic Specialists Conference

Blakely, Logan; Reno, Matthew J.; Peppanen, Jouni

This paper discusses common types of errors that are frequently present in utility distribution system models and which can significantly influence distribution planning and operational assessments that rely on the model accuracy. Based on Google Earth imagery and analysis of correlation coefficients, this paper also illustrates some common error types and demonstrates methods to correct the errors. Error types include misla-beled interconnections between customers and service transformers, three-phase customers labeled as single-phase, unmarked transformers, and customers lacking coordinates. Identifying and correcting for these errors is critical for accurate distribution planning and operational assessments, such as load flow and hosting capacity analysis.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Distribution Feeder Fault Comparison Utilizing a Real-Time Power Hardware-in-the-Loop Approach for Photovoltaic System Applications

Conference Record of the IEEE Photovoltaic Specialists Conference

Darbali-Zamora, Rachid; Hernandez Alvidrez, Javier H.; Summers, Adam; Gurule, Nicholas S.; Reno, Matthew J.; Johnson, Jay B.

Power outages are a challenge that utility companies must face, with the potential to affect millions of customers and cost billions in damage. For this reason, there is a need for developing approaches that help understand the effects of fault conditions on the power grid. In distribution circuits with high renewable penetrations, the fault currents from DER equipment can impact coordinated protection scheme implementations so it is critical to accurately analyze fault contributions from DER systems. To do this, MATLAB/Simulink/RT-Labs was used to simulate the reduced-order distribution system and three different faults are applied at three different bus locations in the distribution system. The use of Real-Time (RT) Power Hardware-in-the-Loop (PHIL) simulations was also used to further improve the fidelity of the model. A comparison between OpenDSS simulation results and the Opal-RT experimental fault currents was conducted to determine the steady-state and dynamic accuracy of each method as well as the response of using simulated and hardware PV inverters. It was found that all methods were closely correlated in steady-state, but the transient response of the inverter was difficult to capture with a PV model and the physical device behavior could not be represented completely without incorporating it through PHIL.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Distribution Feeder Fault Comparison Utilizing a Real-Time Power Hardware-in-the-Loop Approach for Photovoltaic System Applications

Conference Record of the IEEE Photovoltaic Specialists Conference

Darbali-Zamora, Rachid; Hernandez Alvidrez, Javier H.; Summers, Adam; Gurule, Nicholas S.; Reno, Matthew J.; Johnson, Jay B.

Power outages are a challenge that utility companies must face, with the potential to affect millions of customers and cost billions in damage. For this reason, there is a need for developing approaches that help understand the effects of fault conditions on the power grid. In distribution circuits with high renewable penetrations, the fault currents from DER equipment can impact coordinated protection scheme implementations so it is critical to accurately analyze fault contributions from DER systems. To do this, MATLAB/Simulink/RT-Labs was used to simulate the reduced-order distribution system and three different faults are applied at three different bus locations in the distribution system. The use of Real-Time (RT) Power Hardware-in-the-Loop (PHIL) simulations was also used to further improve the fidelity of the model. A comparison between OpenDSS simulation results and the Opal-RT experimental fault currents was conducted to determine the steady-state and dynamic accuracy of each method as well as the response of using simulated and hardware PV inverters. It was found that all methods were closely correlated in steady-state, but the transient response of the inverter was difficult to capture with a PV model and the physical device behavior could not be represented completely without incorporating it through PHIL.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Visualization Methods for Quasi-Static Time-Series (QSTS) Simulations with High PV Penetration

Conference Record of the IEEE Photovoltaic Specialists Conference

Azzolini, Joseph A.; Reno, Matthew J.; Lave, Matthew S.

Distribution system analysis requires yearlong quasi-static time-series (QSTS) simulations to accurately capture the variability introduced by high penetrations of distributed energy resources (DER) such as residential and commercial-scale photovoltaic (PV) installations. Numerous methods are available that significantly reduce the computational time needed for QSTS simulations while maintaining accuracy. However, analyzing the results remains a challenge; a typical QSTS simulation generates millions of data points that contain critical information about the circuit and its components. This paper provides examples of visualization methods to facilitate the analysis of QSTS results and to highlight various characteristics of circuits with high variability.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Implementation of Temporal Parallelization for Rapid Quasi-Static Time-Series (QSTS) Simulations

Conference Record of the IEEE Photovoltaic Specialists Conference

Azzolini, Joseph A.; Reno, Matthew J.; Montenegro, Davis

Quasi-static time-series (QSTS) analysis of distribution systems can provide critical information about the potential impacts of high penetrations of distributed and renewable resources, like solar photovoltaic systems. However, running high-resolution yearlong QSTS simulations of large distribution feeders can be prohibitively burdensome due to long computation times. Temporal parallelization of QSTS simulations is one possible solution to overcome this obstacle. QSTS simulations can be divided into multiple sections, e.g. into four equal parts of the year, and solved simultaneously with parallel computing. The challenge is that each time the simulation is divided, error is introduced. This paper presents various initialization methods for reducing the error associated with temporal parallelization of QSTS simulations and characterizes performance across multiple distribution circuits and several different computers with varying architectures.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Unintentional Islanding Evaluation Utilizing Discrete RLC Circuit Versus Power Hardware-in-the Loop Method

Conference Record of the IEEE Photovoltaic Specialists Conference

Gonzalez, Sigifredo; Desarden-Carrero, Edgardo; Gurule, Nicholas S.; Aponte-Bezares, Erick E.

The high penetration of photovoltaic (PV) distributed energy resources (DER) facilitates the need for today's systems to provide grid support functions and ride-through voltage and frequency events to minimize the adverse impacts on the distribution power system. These new capabilities and its requirements have created concerns that autonomous unintentional islanding (UI) algorithms are not sufficient to prevent a condition were the loss of utility is detected. Type tests in IEEE 1547-2018 have evolved to thoroughly evaluate DER capabilities and a new method includes power hardware-in-the-loop (PHIL) testing. Sandia National Laboratories is performing a detailed laboratory comparison of the tuned Resistive, Inductive, Capacitive (RLC) circuit method using discrete elements andthe PHIL that applies the PV inverter equipment under test (EUT), real-time simulator, and a power amplifier. The PHIL method allows UI assessments without the need for potentially expensive, large,heat generating discrete loads.

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TYPE Conference Poster YEAR 2019
OSTIScopus

Implementation of Temporal Parallelization for Rapid Quasi-Static Time-Series (QSTS) Simulations

Conference Record of the IEEE Photovoltaic Specialists Conference

Azzolini, Joseph A.; Reno, Matthew J.; Montenegro, Davis

Quasi-static time-series (QSTS) analysis of distribution systems can provide critical information about the potential impacts of high penetrations of distributed and renewable resources, like solar photovoltaic systems. However, running high-resolution yearlong QSTS simulations of large distribution feeders can be prohibitively burdensome due to long computation times. Temporal parallelization of QSTS simulations is one possible solution to overcome this obstacle. QSTS simulations can be divided into multiple sections, e.g. into four equal parts of the year, and solved simultaneously with parallel computing. The challenge is that each time the simulation is divided, error is introduced. This paper presents various initialization methods for reducing the error associated with temporal parallelization of QSTS simulations and characterizes performance across multiple distribution circuits and several different computers with varying architectures.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Vacuum Insulator Flashover of Ultra High Vacuum Compatible Insulators

IEEE International Pulsed Power Conference

Leckbee, Joshua L.; Simpson, Sean S.; Ziska, Derek Z.; Bui, B.

High voltage vacuum systems with stringent vacuum requirements are often designed with ceramic insulators which have low flashover strength. In this paper, we report on experimental results comparing pulsed high voltage flashover of Rexolite®(cross-linked polystyrene), a pulsed power industry standard vacuum insulator, to Kel-F® (polyclorotrifluoroethylene), a plastic with significantly lower vacuum outgassing. Our results show similar surface flashover results with the two materials, with both exhibiting large spread in flashover electric field. The average electric field for flashover of each material agree well with predictions based on previously published results.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Single Diode Parameter Extraction from In-Field Photovoltaic I-V Curves on a Single Board Computer

Conference Record of the IEEE Photovoltaic Specialists Conference

Jones, Christian B.; Hansen, Clifford H.

In this paper, we present a new, light-weight approach for extracting the five single diode parameters (IL, Io, RS, RSH, and nNsVt) for advanced, in-field monitoring of in situ current and voltage (I-V) tracing devices. The proposed procedure uses individual I-V curves, and does not require the irradiance or module temperature measurement to calculate the parameters. It is suitable for operation on a small, single board computer at the point of I-V curve measurement. This allows for analysis to occur in the field, and eliminates the need to transfer large amounts of data to centralized databases. Observers can receive alerts directly from the in-field devices based on the extraction, and analysis of the commonly used single diode equivalent model parameters. This paper defines the approach and evaluates its accuracy by subjecting it to I-V curves with known parameters. Its performance is defined using actual I-V curves generated from an in situ scanning devices installed within an actual photovoltaic production field. The algorithm is able to operate at a high accuracy for multiple module types and performed well on actual curves extracted in the field.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Electro-Optical Measurement of Electric Fields for Pulsed Power Systems

IEEE International Pulsed Power Conference

Owens, Israel O.; Grabowski, Theodore C.; Joseph, N.; Coffey, Sean K.; Ulmen, Benjamin A.; Kirschner, Debra S.; Rainwater, Kirk R.; Struve, Kenneth W.

The electric field strength between the cathode and anode (i.e., the voltage) of a pulsed power machine is one of the most important operating parameters of the device. However, to date, accurate and precise voltage measurements on these high energy pulsed power systems have proved difficult if not virtually impossible to perform. In many cases, the measurements to be performed take place in an environment cluttered with electromagnetic interference (EMI), radio frequency interference (RFI), and electron pollution, and there is the potential for electrical discharge (or arcing), there is limited physical access, or the measurement area is deemed unsuitable due to radiation safety concerns. We report on an electro-optical-based approach to measuring strong, narrow-pulse-width electric fields that requires no interfering metallic probes or components to disturb the field to be measured. Here we focus on device theory, operating parameters and a laboratory experiment.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Geographic Assessment of Photovoltaic Module Environmental Degradation Stressors

Conference Record of the IEEE Photovoltaic Specialists Conference

Jones, Christian B.; Karin, Todd; Jain, Anubhav; Hobbs, William B.; Libby, Cara

Environmental stress can degrade photovoltiac (PV) modules. We perform a literature search to identify models that estimate the damage caused by exposure to various environmental stressors, including temperature, radiation, and humidity. The weather-related variables, including ambient temperature, irradiance and humidity are calculated using the Global Land Data Assimilation System (GLDAS). The analysis also calculated degradation-model stressors, module temperature, plane of array irradiance, and relative humidity and compared these PV-specific variables to identify correlations and the translation required to represent the stressor accurately. The results show that global horizontal (GHI) irradiance can be used instead of plane-of-array irradiance to represent radiation dose. However, module temperature can be significantly different from ambient temperatures and specific humidity is significantly different from relative humidity.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Grid-forming Inverter Experimental Testing of Fault Current Contributions

Conference Record of the IEEE Photovoltaic Specialists Conference

Gurule, Nicholas S.; Hernandez Alvidrez, Javier H.; Reno, Matthew J.; Summers, Adam; Gonzalez, Sigifredo G.; Flicker, Jack D.

Historically, photovoltaic inverters have been grid-following controlled, but with increasing penetrations of inverter-based generation on the grid, grid-forming inverters (GFMI) are gaining interest. GFMIs can also be used in microgrids that require the ability to interact and operate with the grid (grid-tied), or to operate autonomously (islanded) while supplying their corresponding loads. This approach can substantially improve the response of the grid to severe contingencies such as hurricanes, or to high load demands. During islanded conditions, GFMIs play an important role on dictating the system's voltage and frequency the same way as synchronous generators do in large interconnected systems. For this reason, it is important to understand the behavior of such grid-forming inverters under fault scenarios. This paper focuses on testing different commercially available grid-forming inverters under fault conditions.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Large Acoustoelectric Effect in Wafer Bonded Indium Gallium Arsenide / Lithium Niobate Heterostructure Augmented by Novel Gate Control

2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII

Siddiqui, Aleem M.; Hackett, Lisa A.; Dominguez, Daniel D.; Tauke-Pedretti, Anna; Friedmann, Thomas A.; Peake, Gregory M.; Miller, Michael R.; Douglas, James K.; Eichenfield, Matthew S.

This paper demonstrates a monolithic surface acoustic wave amplifier fabricated by state-of-the-art heterogenous integration of a IH-V InGaAs-based epitaxial material stack and LiNb03. Due to the superior properties of the materials employed, we observe electron gain and also non-reciprocal gain in excess of 30dB with reduced power consumption. Additionally, we present a framework for performance optimization as a function of material parameters for a targeted gain. This platform enables further advances in active and non-reciprocal piezoelectric acoustic devices.

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TYPE Conference Poster YEAR 2019
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EXPERIMENTAL RESULTS FROM THE 1.2 MA 2.2 m DIAMETER LINEAR TRANSFORMER DRIVER AT SANDIA NATIONAL LABS

Douglass, Jonathan D.; Hutsel, Brian T.; Leckbee, Joshua J.; Stoltzfus, Brian S.; Wisher, Matthew L.; Savage, Mark E.; Stygar, William A.; Breden, E.W.; Calhoun, Jacob D.; Cuneo, M.E.; Jaramillo, Deanna M.; Johns, Owen J.; Jones, Michael J.; Lucero, Diego J.; Moore, James M.; Sceiford, Matthew S.; Kiefer, Mark L.; Mulville, Thomas D.; Sullivan, Michael A.; Hohlfelder, Robert J.

Abstract not provided.

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TYPE Conference Poster YEAR 2019
DOIOSTI
Results 21401–21600 of 96,771
Results 21401–21600 of 96,771