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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

The introduction of space technology power systems into developing countries

Between 1978 and 1984, NASA-Lewis was responsible for the design, fabrication, installation and operational support of 57 photovoltaic power systems in 27 countries. These systems were installed in locations not served by a central power system and ranged in size from 40 W for powering street lights to 29 kW for providing power to a complete village. Several of the system projects had socio/economic studies components that provided for an assessment of how the introduction of both electricity and a novel high technology power system affected the users and their society.

Roberts, Allen F.↗
NASA NTRS2018

Radioisotope Power Systems to Enable Extended Lunar Science and In-Situ Resource Utilization Missions

The Moon's surface environment offers a significant challenge for most space systems and, particularly, for power technologies. First, the Moon's rotational synodic period is 27.3 days long because it is tidally-locked with Earth and thus matches its orbital period. However, for a point on the lunar surface with respect to the Sun returning to the same position in the sky, called a synodic day, is 29.5 days or 708 hours. Therefore, a lunar day is 354 hours of sunlight and 354 hours of darkness. Equatorial diurnal temperatures range from about 400K at noon to 100K during the night. Within craters and permanently shadowed regions (PSRs) temperatures can be a constant 40K or below. Sunlight in the lunar polar regions can range from total darkness in deep polar craters and at higher elevations, potentially nearly continuous conditions are possible. However local topographical features such as outcrops or more distant mountains and ridges would obscure the Sun even in these extended sunlit areas and thus create intermittent shadowed periods depending on seasonally varying Sun angle and the obscuring topographical features. Thus, the power system technology that a mission selects becomes a critical trade.

radioisotope↗
NASA NTRSDate not supplied

Advanced Modular Power Systems (AMPS) Project 101

This presentation provides an overview of the Advanced Modular Power Systems (AMPS) Project, along with sections to describe the three technical focus areas - Modular Power Electronics & Standards, Autonomous Power Control, and the Modular Power Testbed.

Modular Power↗
DOE OSTI2023

Reevaluating Contour Visualizations for Power Systems Data

Effective visual analytics tools are needed now more than ever as emerging energy systems data and models are rapidly growing in scale and complexity. Here we examined the suitability of colored contour maps to visually represent bus values in two different power system models: a dense 24k-bus distribution system and a 240-bus transmission system. In a quantitative analysis, we found that contour maps misrepresent power systems data, changing the statistical dispersion of the bus values, including the loss of extreme values. In a controlled empirical study with thirty professional power system research engineers, we found that these distortions significantly impact excursion identification tasks. Additionally, the engineers were less confident in their assessments using contour-based visualizations than glyph-based visualizations.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1990

Modeling and simulation of the space platform power system

A comprehensive computer-aided modeling and simulation technique for the space platform power system is described. Large-signal and small-signal modeling is presented for the system components. The component models have been integrated to form the complete power system model. The system model is shown to be a powerful tool in simulating the behavior of the system with variation of illumination level and load. It can be used to study the bus regulation in each mode and to observe mode changes as the solar array is subjected to transitions from sunlight to eclipse and back to sunlight. System simulations show how the bus regulation is maintained by activating the shunt switching unit, the charger, or the discharger, depending on the available illumination level. The system model is suitable for verifying hardware results of for analyzing the performance of a proposed system where hardware testing is not feasible. The EASY5 dynamic analysis program is used as the host software for the modeling and simulation.

Patil, A. R.↗
DOE OSTI2024

Using Co-Simulation to Model Interconnect-Scale Power Systems from Loads to Generators

Co-simulation is a modeling technique that allows analysts to combine simulation tools and their corresponding models to exchange data during run-time, allowing the creation of larger and more complex models across heterogeneous domains. HELICS is a co-simulation platform developed over the past six years that has been shown to be effective for these multi-domain analysis. Recently, a HELICS-based analysis was completed where the ERCOT electrical interconnect in the United States was modeled in high detail from bulk power system generation to individual customer loads. This model was used to evaluate a flat-rate and transactive energy tariff with integrated wholesale and retail real-time and day-ahead energy markets. This modeling allows detailed analysis showing how the operations of the power system under these tariffs impact all actors in the power system, from individual customers to bulk power system operators.

co-simulation, HELICS, transactive energy system, ↗
NASA NTRS1978

An economical approach to space power systems

Projected energy demand for all NASA, DoD and civil missions for the time span 1981 to 1995 are illustrated. Typical energy cost range from about $300 to $2000 per kW-hr, with an average of about $800 per kW-hr for long-duration missions. At these levels, the cost of the required energy would be several billion dollars per year by about 1985 and might constrain the number and types of NASA programs to be carried out. NASA is extensively pursuing approaches for reducing nonrecurring costs. Two programs are presented for the development of an economical approach to space power systems. They are: (1) Economical Orbital Power (ECOP) with the objective to demonstrate the applicability of a commercial approach to the development of a low cost photovoltaic space power system; and (2) Space Power Experiment (SPEX) which has the objective to demonstrate the application of industrial hardware for space power systems.

Teren, F.↗
DOE OSTI2020

Fast and Accurate Frequency Response Estimation for Large Power System Disturbances Using Second Derivative of Frequency Data

Accurate Frequency Response Estimation (FRE) is critical to reliability risk management of large power system disturbances. This letter proposes a measurement-driven approach for FRE by calculating the second derivative of frequency from synchrophasor data. Compared with conventional methods, the proposed method has major advantages of low computational burden and high accuracy, which makes it appropriate for real-time FRE in bulk power systems. The effectiveness of this method is validated with actual synchrophasor data on 96 confirmed historical power system disturbances in the U.S. eastern interconnection.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1990

Knowledge-based and integrated monitoring and diagnosis in autonomous power systems

A new technique of knowledge-based and integrated monitoring and diagnosis (KBIMD) to deal with abnormalities and incipient or potential failures in autonomous power systems is presented. The KBIMD conception is discussed as a new function of autonomous power system automation. Available diagnostic modelling, system structure, principles and strategies are suggested. In order to verify the feasibility of the KBIMD, a preliminary prototype expert system is designed to simulate the KBIMD function in a main electric network of the autonomous power system.

Momoh, J. A.↗
DOE OSTI2020

High-Temperature Heat Transfer Fluid Circulator for Concentrating Solar Power Systems

Concentrating Solar Power (CSP) plants with Thermal Energy Storage (TES), require compressors capable of circulating supercritical carbon dioxide (sCO2) heat transfer fluids (HTFs) at temperatures from 500 to 700+°C and pressures from 8 to 25 MPa (80 to 250 Bar or 1160 to 3626 psia) in order to achieve thermal-to-electric efficiencies >50%. A review of papers relating to SCO2 compressors reveals that in almost every case the conditions being considered either allow for cooling of the SCO2 working fluid or are considering operating conditions close to the critical point at a temperature and pressure of approximately 31°C and 1070 psi). While the technology reported in these papers is relevant to most turbomachinery, the current CSP gas pathway circulator operating pressures are well above the CO2 critical point and do not allow for cooling of the main HTF flow. The purpose of this paper was to describe the key system issues affecting the design of a HTF circulator that could be scaled from a small size research and proof of concept circulator compressor to sizes supporting power plants producint upwards of 100 to 300 Mega Watts of electrical power. Due to the high temperatures and pressures the research scale HTF circulator was designed to be hermetically sealed to prevent leakage of the super critical carbon dioxide to the environment. In order to achieve hermetic sealing the drive motor and centrifugal impeller were fully integrated in a single shaft system configuration. From a preliminary assessment of compression power as a function of operating speed and impeller diameter it was determined that a smaller, higher speed impeller would result in a more efficient circulator. However, due to the high pressure and corresponding density of the sCO2 coupled with high operating speeds, large windage losses (i.e., viscous drag on the high speed rotating shaft) would occur which could result in a substantial reduction in efficiency of the system. Therefore tradoff studies were complerted to identify the operating speeds and system component sizes to achieve high efficiency. Based on the trade studies, the final design was a 55 mm diamter compressor impeller operating at speeds to 85,000 rpm. The unit will be built and tested in the future. Key Words: Super Critical Carbon Dioxide, Heat Transfer Fluid, Turbomachinery, Compressor, Circulator, Critical Point, Concentrating Solar Power, Solar Energy

Super Critical Carbon Dioxide, Heat Transfer Fluid↗
NASA NTRS1990

Discharge transient coupling in large space power systems

Experiments have shown that plasma environments can induce discharges in solar arrays. These plasmas simulate the environments found in low earth orbits where current plans call for operation of very large power systems. The discharges could be large enough to couple into the power system and possibly disrupt operations. Here, the general concepts of the discharge mechanism and the techniques of coupling are discussed. Data from both ground and flight experiments are reviewed to obtain an expected basis for the interactions. These concepts were applied to the Space Station solar array and distribution system as an example of the large space power system. The effect of discharges was found to be a function of the discharge site. For most sites in the array discharges would not seriously impact performance. One location at the negative end of the array was identified as a position where discharges could couple to charge stored in system capacitors. This latter case could impact performance.

Stevens, N. John↗
NASA NTRS2013

Cold-End Subsystem Testing for the Fission Power System Technology Demonstration Unit

The Fission Power System (FPS) Technology Demonstration Unit (TDU) consists of a pumped sodiumpotassium (NaK) loop that provides heat to a Stirling Power Conversion Unit (PCU), which converts some of that heat into electricity and rejects the waste heat to a pumped water loop. Each of the TDU subsystems is being tested independently prior to full system testing at the NASA Glenn Research Center. The pumped NaK loop is being tested at NASA Marshall Space Flight Center; the Stirling PCU and electrical controller are being tested by Sunpower Inc.; and the pumped water loop is being tested at Glenn. This paper describes cold-end subsystem setup and testing at Glenn. The TDU cold end has been assembled in Vacuum Facility 6 (VF 6) at Glenn, the same chamber that will be used for TDU testing. Cold-end testing in VF 6 will demonstrate functionality; validated coldend fill, drain, and emergency backup systems; and generated pump performance and system pressure drop data used to validate models. In addition, a low-cost proof-of concept radiator has been built and tested at Glenn, validating the design and demonstrating the feasibility of using low-cost metal radiators as an alternative to highcost composite radiators in an end-to-end TDU test.

Briggs, Mazwell↗
DOE OSTI2020

Advanced Gas Turbine and sCO 2 Combined Cycle Power System (Final Report)

The team of Southwest Research Institute (SwRI), Hanwha Power Systems Americas (HPSA), and Solar Turbines Incorporated (Solar) has worked to develop a modular, highly efficient combined-cycle power system consisting of a supercritical carbon dioxide (sCO 2 )-based waste-heat recovery system (WHRS) coupled to a Solar Titan 130 gas turbine (GT). During Phase 1 of the project, the project team used advanced thermodynamic cycle and techno-economic modeling to find an optimal sCO 2 WHRS bottoming cycle and machinery configuration for a Solar Titan 130. In addition to this, a conceptual design of the machinery and overall system layout was created and technology gaps were identified.

30 DIRECT ENERGY CONVERSION↗
NASA NTRS1981

Assessment of a satellite power system and six alternative technologies

The satellite power system is assessed in comparison to six alternative technologies. The alternatives are: central-station terrestrial photovoltaic systems, conventional coal-fired power plants, coal-gasification/combined-cycle power plants, light water reactor power plants, liquid-metal fast-breeder reactors, and fusion. The comparison is made regarding issues of cost and performance, health and safety, environmental effects, resources, socio-economic factors, and institutional issues. The criteria for selecting the issues and the alternative technologies are given, and the methodology of the comparison is discussed. Brief descriptions of each of the technologies considered are included.

Wolsko, T.↗
NASA NTRS1996

TOPEX/Poseidon Electrical Power System - Performance

This paper shows that the power system performance (batteries, solar array, power regulator) on-board the TOPEX/Poseidon satellite has met or exceeded pre-launch predicitons and has successfully managed the performance of NiCd batteries which had shown anomalous performance on other missions such as UARS and GRO.

batteries↗
DOE OSTI2024

Power System Waveform Datasets for Machine Learning

The desire for increased visibility across the electricity grid will necessarily increase the deployment of sensing and measurement devices and associated data management needs to unprecedented levels. For the existing sensing and measurement infrastructure, there remains a great amount of “value” yet to be extracted through advanced data management and analytics. Availability of more data will not, by itself, lead to changes in grid visibility, security, and resiliency. To create the predictive and prescriptive environment required to enable new markets and transactions for customer revenue and a reliable grid, the data must be collected, organized, evaluated, and analyzed using sophisticated algorithms to provide actionable information allowing operators and customers to reliably manage an increasingly complex grid. Progress in artificial intelligence (AI) has been largely driven by large, publicly available datasets that can be used to train AI algorithms such as MNIST, a database of handwritten images of digits, and ImageNet, an image database of everyday objects. These types of publicly available databases of real-world training datasets have been largely credited for advancement of image processing, computer vision, and deep learning algorithms that these use cases deploy. However, in the power systems industry to date, there are few databases with proper event labeling, and data access to a publicly available collection of power system event waveforms that will allow users to interact with grid signature data. Publicly available datasets of power system event waveforms, such as the DOE/EPRI dataset, often lack critical metadata or contain limited examples of each event type, and data formats vary widely across these datasets.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Distributed Frequency Divider for Power System Bus Frequency Online Estimation Considering Virtual Inertia From DFIGs

In this work, a distributed frequency divider is proposed to estimate power system bus frequency with a limited number of PMUs while considering the inertial contributions from double-fed induction generators (DFIGs). The key idea is to reformulate the original frequency divider by modeling the contributions of DFIGs with inertia emulation and external regional power system through Thevenin equivalents. The distributed frequency divider is general and able to estimate local bus frequencies in a distributed manner. Besides, only the knowledge of the rotor speeds of synchronous generator, boundary bus frequencies and terminal bus frequencies of DFIGs as well as the admittance matrix are required to estimate the frequencies at all buses. This is drastically different from existing approaches that require system observability by PMUs to monitor all bus frequencies. Numerical results carried out on the IEEE 39-bus and modified 118-bus power systems with DFIGs demonstrate and effectiveness and robustness of the proposed method.

24 POWER TRANSMISSION AND DISTRIBUTION↗