Edward J. Simburger

Low Voltage Bulk Power System Restoration Simulation

Time is the crucial element in restorative state control for electric power systems. One method for reenergizing large portions of a blacked out electric power system with a minimum of switching and thus time to restoration, is described. Results of a simulated system restart utilizing actual power system facilities are compared to power flow studies. The simulation tests were performed on the Los Angeles Department of Water and Power (LADWP) system in order to verify the concept of utilizing generation operating at extremely low voltage to energize as large a part as possible of the unloaded bulk power transmission system located within the service area.

Load Following Impacts of a Large Wind Farm on an Imterconnected Electric Utility System

A major issue encountered in the use of many of the renewable energy resources for the production of electric power is the variability of the resource itself. This paper presents the results of a dynamic simulation of the long term power system responses to changes in the load and generation patterns resulting from significant penetrations of renewable resource technologies. The renewable technology selected for this study is a large wind farm with a total output of 500 MW added to the 1979 generation base of the Los Angeles Department of Water and Power system.

Anomalous solar array performance on GPS

The general issue of degradation of optical surfaces on spacecraft is reviewed in order to understand the observed behavior of the Navstar solar cell arrays. The solar arrays on GPS Navstars 1-6 have shown anomalous degradation during the 5-year mission life and beyond. The departure from predicted performance consists of an extra 2.5% per year degradation in excess of the radiation model estimates. Examination of optical solar reflector (OSR) data from a variety of spacecraft reveals variations in OSR degradation rates which correlate with the vehicle design. These data support the idea that contaminants outgassing from the vehicle are photodeposited on the optical surfaces, leading to degradation of their reflectivity. Contamination data taken from an OSR flown on Navstar 5 are used to predict the solar cell array degradation. The predicted effect of contamination on the array output is consistent with the observed behavior of the five Block I vehicles.<<ETX>>

A MULTIFUNCTIONAL FLEXURE HINGE FOR DEPLOYING OMNIDIRECTIONAL SOLAR ARRAYS

The Aerospace Corporations DARPA-Aerospace PICOSAT project will, in the near term, deploy a thin-film solar array as a power source for its small satellite. The deployment mechanism for the array is unique because it cannot employ conventional booms, hinges, latches, or stops, due to the extremely limited room available. In order to stow thin-film solar cell arrays in the most compact manner, a flexure hinge made of an extremely flexible metal has been suggested. In this paper, the prior use of the superelastic Ti-Ni alloy for the structure, hinge and unfolding energy device, is extended to include the function of a latch that locks the deployed structure in place and the electrical bus which carries current from the cells back to the satellite. By performing all these functions with a single element, the complexity and cost of the array is reduced, the assembly process is simplified and the reliability increased.

Engineering Design for a Central Station Photovoltaic Power Plant

The engineering design effort presented in this paper is an attempt to bring the various components and subsystems that would be required in a Central Station Photovoltaic Power Plant together in the form of a complete preliminary engineering design for the plant. The design identifies all of the subsystems and defines the interfaces required for integrating each subsystem into the total plant system. The resultant preliminary engineering design can be used for further subsystem optimization and tradeoff studies.

Advancements in the development of thin film amorphous silicon space solar cell for the PowerSphere concept

The authors describe how the development of the PowerSphere concept over the last year focused on the design and fabrication of amorphous silicon solar cells that would meet the space environmental requirements. This is a cooperative effort between The Aerospace Corporation and Iowa Thin Film Technologies, Inc. Modifications to the terrestrial product line necessary to produce a thin film amorphous silicon solar cell suitable for space applications have been identified. A number of experiments have been performed in The Aerospace Corporations Laboratories to develop a more robust top contact to collect cell current for the otherwise terrestrial cell produced by Iowa Thin Film Technologies production line. The up-to-date results of this effort are presented in this paper.

Proton Irradiation and Annealing of a -Si Thin -Film Solar Cells for Space Applications: Results at 160 keV

†, ‡ § ** , Thin -film solar cells are of interest for satellite power generation because of the potential advantages in terms of having hig her specific power (lightweight), lower specific volume (flexible), and higher end -of -life power (superior radiation resistance), as compared to the crystalline solar cells. The space radiation environment causes gradual solar cells performance degradatio n, thus limiting the lifetime of the solar array. Due to the self annealing effect, the radiation damage on thin -film solar cells can be partially reversed. This paper presents proton irradiation and annealing of amphorous silicon (a -Si) solar cell test results.

Space radiation environmental testing on POSS coated solar cell coverglass

Light weight, flexible, radiation hardened solar cells coatings are of interest for applications on satellite power generation owing to the potential advantages in terms of having higher specific power (lightweight), lower specific volume (flexible), and higher end-of-life power (superior radiation resistance), as compared to current state-of-the-art Ce-doped micro sheet solar cell coverglass. The space radiation environment causes gradual optical performance degradation of coverglass and coatings, thus limiting the lifetime of the solar array. The objective of this project is to assess the POSS (polyhedral oligomeric silsesquioxane) coating in simulated space proton radiation environments. Due to the unique molecular structure, POSS may be equipped with suitable optical property along with superior radiation hardness, thus better protecting the solar cells.

Thin-Film Photovoltaic Radiation Testing for Space Applications

Although thin-film photovoltaic technology on lightweight flexible substrates has lower beginning-of-life efficiency compared to traditional single crystalline solar cells, it can offer advantages in high-specific power and low-stowed volume for power generation in space. To date, radiation testing on thin-film solar cells has demonstrated superior radiation hardness compared to traditional crystalline solar cells. In addition, radiation induced damage in thin-film solar cells can be removed by annealing at temperatures readily achievable in space. Prior to deployment of this new technology for any mission, a more thorough understanding of its performance in the space environment will be required. The Aerospace Corporation has initiated a comprehensive study of thin-film solar cell performance in a simulated space radiation environment. A new testbed has been constructed to study the combined space environmental effect of proton irradiation and air mass zero light spectrum light soaking on a thin-film photovoltaic

Engineering Development Model Testing of the PowerSphere

The Aerospace Corporation, NASA Glenn Research Center, Lockheed-Martin, and ILC Dover over the past two years have been engaged in developing a Multifunctional Inflatable Structure for the PowerSphere Concept under contract with NASA (NAS3-01115). The PowerSphere concept consists of a relatively large spherical solar array, which would be deployed from a micro satellite. 1–8 The PowerSphere structure and the deployment method was patented by the Aerospace Corporation (U.S. Patent Numbers 6,284,966 B1 and 6,318,675). The work on this project has resulted in a number of technological innovations in the state of the art for integrating flexible thin-film solar cells with flex circuit harness technology and inflatable ultraviolet-light-rigidizable structures.