Search NASA⌕ Search

SEARCH · Search NASA

Results for “INTERCONNECTED POWER SYSTEMS”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Widespread Loss of Communications in Grid Systems: Impacts and Response Strategies

This report explores the reliance on communication systems for bulk grid operations and considers selected options as a supplement to cyber security. The extreme scenario of a complete loss of communications for power grid operation is assessed, presenting a bounded, worst-case perspective. The paper explores grid communications failures and how a system modifications can, at an increased cost, retain a moderate level of preparedness for a loss of communications and control when used in partnership with cyber security protocols. Doing so allows the increased economic and secure operation that communication based controls affords, but also ensures a level of resilient operation if they are lost. The motivation of this paper is due to the proliferation of photovoltaic (PV) resources, and more generally, smart-grid resources within the US grid, which are requiring more and more active and wide-area controls. Though the loss of communication and control can affect nearly any grid control system, the risk of losing load at large scales requires a broad view of system interconnectivity, so it has been evaluated from a transmission perspective in this report.

14 SOLAR ENERGY↗
DOE OSTI2020

High-Frequency Signature-Based Fault Detection for Future MV Distribution Grids: Preprint

Increased deployment of Distributed Energy Resources (DERs) and microgrids are significantly changing the operation of distribution grid. Increasing penetration of power electronics based DERs also raise several operational problems such as protection coordination issues, voltage raise, recloser synchronization, stability, and frequency control. Legacy systems are designed for unidirectional power flow. Bidirectional power flows, and varying short circuit levels are some of the major challenges in implementing these legacy protection schemes for future power grid with high penetration of power electronics based DERs. Inverter based DER’s can contribute to a maximum of 2 p.u. fault current. Interconnection standards might require even lower fault current contribution. If these protection related challenges are not addressed, it will result in limiting the penetration of DERs in distribution feeders. In this paper, the feasibility of high frequency signature generated by transients is evaluated to identify and locate faults in a distribution system. The paper will discuss the need for an accurate line modeling approach to accurately capture the high frequency signatures. These high frequency signatures are naturally occurring electromagnetic transients for events such as switching events in the network, faults events, etc. This is different than that implemented in transmission systems as the proposed approach utilizes advanced signal processing techniques to retrieve valuable information from the high frequency signatures generated during faults and does not just rely on time delay measurements between reflections of the high frequency signals. In the full paper, information of a modified IEEE distribution feeder test system to accurately model the high frequency signatures will be provided. The distribution lines will be modeled using universal line modeling (ULM) technique in an electromagnetic transients program (EMTP) modeling platform. Different test cases will be simulated and these test cases will include different fault types, multiple fault locations, capacitor bank switching, etc. The feeder system modeled for these simulations will also include power electronics based DERs. Additionally, experimental results demonstrating the high frequency signatures generated due to a transient event in a medium voltage (13.8 kV) distribution line will also be presented in the full paper. Furthermore, the analysis combined with simulation and experimental results in the full paper will help demonstrate the feasibility and efficacy of the proposed protection scheme. The developed protection scheme will not just help solve problems generated by bidirectional current flow, varying short-circuit current capacity, but also help in proliferation of DERs in distribution systems.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2020

Analyzing the Effects of Cyberattacks on Distribution System State Estimation: Preprint

Key components of power systems—such as energy management systems, automatic generation control, and state estimation—are under serious vulnerability from cyber attacks. Cyber threats in electric grids have increased significantly because of the increased interconnectivity of supervisory control and data acquisition systems and public network infrastructure. As the penetration level of distributed energy resources increases, it is imperative to employ system-monitoring techniques such as state estimation for the reliable operation of distribution systems. Recently, multiple methods have been developed that exploit the low rank property of distribution system state matrix and are robust to bad data, such as matrix completion. This paper analyzes the impact of various realistic cyber attack scenarios on matrix completion. Realistic cyber attack scenarios are converted into data corruption models that are used in an extensive simulation of a custom IEEE 123-bus system.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2014

Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska final report

The Aleutian Pribilof Islands Association was awarded a U.S. Department of Energy Tribal Energy Program grant (DE-EE0005624) for the Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska (Project). The goal of the Project was to perform a feasibility study to determine if a tidal energy project would be a viable means to generate electricity and heat to meet long-term fossil fuel use reduction goals, specifically to produce at least 30% of the electrical and heating needs of the tribally-owned buildings in False Pass. The Project Team included the Aleut Region organizations comprised of the Aleutian Pribilof Island Association (APIA), and Aleutian Pribilof Island Community Development Association (APICDA); the University of Alaska Anchorage, ORPC Alaska a wholly-owned subsidiary of Ocean Renewable Power Company (ORPC), City of False Pass, Benthic GeoScience, and the National Renewable Energy Laboratory (NREL). The following Project objectives were completed: collected existing bathymetric, tidal, and ocean current data to develop a basic model of current circulation at False Pass, measured current velocities at two sites for a full lunar cycle to establish the viability of the current resource, collected data on transmission infrastructure, electrical loads, and electrical generation at False Pass, performed economic analysis based on current costs of energy and amount of energy anticipated from and costs associated with the tidal energy project conceptual design and scoped environmental issues. Utilizing circulation modeling, the Project Team identified two target sites with strong potential for robust tidal energy resources in Isanotski Strait and another nearer the City of False Pass. In addition, the Project Team completed a survey of the electrical infrastructure, which identified likely sites of interconnection and clarified required transmission distances from the tidal energy resources. Based on resource and electrical data, the Project Team developed a conceptual tidal energy project design utilizing ORPC’s TidGen® Power System. While the Project Team has not committed to ORPC technology for future development of a False Pass project, this conceptual design was critical to informing the Project’s economic analysis. The results showed that power from a tidal energy project could be provided to the City of False at a rate at or below the cost of diesel generated electricity and sold to commercial customers at rates competitive with current market rates, providing a stable, flat priced, environmentally sound alternative to the diesel generation currently utilized for energy in the community. The Project Team concluded that with additional grants and private investment a tidal energy project at False Pass is well-positioned to be the first tidal energy project to be developed in Alaska, and the first tidal energy project to be interconnected to an isolated micro grid in the world. A viable project will be a model for similar projects in coastal Alaska.

16 TIDAL AND WAVE POWER↗
DOE OSTI2012

Geothermal Power and Interconnection: The Economics of Getting to Market

This report provides a baseline description of the transmission issues affecting geothermal technologies. It is intended for geothermal experts in either the private or public sector who are less familiar with how the electricity system operates beyond the geothermal plant. The report begins with a comprehensive overview of the grid, how it is planned, how it is used, and how it is paid for. The report then overlays onto this "big picture" three types of geothermal technologies: conventional hydrothermal systems; emerging technologies such as enhanced engineered geothermal systems (EGS) and geopressured geothermal; and geothermal co-production with existing oil and gas wells. Each category of geothermal technology has its own set of interconnection issues, and these are examined separately for each. The report draws conclusions about each technology’s market affinities as defined by factors related to transmission and distribution infrastructure. It finishes with an assessment of selected markets with known geothermal potential, identifying those that offer the best prospects for near-term commercial development and for demonstration projects.

15 GEOTHERMAL ENERGY↗
NASA NTRS1981

Review of biased solar arraay. Plasma interaction studies

The Solar Electric Propulsion System (SEPS) is proposed for a variety of space missions. Power for operating SEPS is obtained from large solar array wings capable of generating tens of kilowatts of power. To minimize resistive losses in the solar array bus lines, the array is designed to operate at voltages up to 400 volts. This use of high voltage can increase interactions between the biased solar cell interconnects and plasma environments. With thrusters operating, the system ground is maintained at space plasma potential which exposes large areas of the arrays at the operating voltages. This can increase interactions with both the natural and enhanced charged particle environments. Available data on interactions between biased solar array surfaces and plasma environments are summarized. The apparent relationship between collection phenomena and solar cell size and effects of array size on interactions are discussed. The impact of these interactions on SEPS performance is presented.

Stevens, N. J.↗
DOE OSTI2016

Reaching new solar heights: integrating high penetrations of PV into the power system

Installed capacity of solar photovoltaics (PV) continues to grow rapidly in the US. High penetrations and can create operational and reliability challenges. PV integration shares some attributes and mitigation strategies with wind, and differs in some key ways that will be discussed. This study investigates PV integration challenges and examines mitigation issues for utilities planning for high penetrations of PV, with a focus on the Western Interconnection of the US. System balancing becomes more difficult due to a duck‐shaped net load curve. Flexibility in the remaining generators, load, and the PV itself, is critical in balancing the system. Reliability impacts from PV have been studied less and addressed less than system balancing issues, but become more important at high penetrations. Understanding essential reliability services from PV, weak grid issues with PV, and distributed PV impacts on bulk power system reliability is critical for planning of high penetrations of PV.

Lew, Debra↗
DOE OSTI2014

Frequency Regulation and Oscillation Damping Contributions of Variable-Speed Wind Generators in the U.S. Eastern Interconnection (EI)

The U.S. Eastern Interconnection (EI) is one of the largest electric power grids in the world and is expected to have difficulties in dealing with frequency regulation and oscillation damping issues caused by the increasing wind power. On the other side, variable-speed wind generators can actively engage in frequency regulation or oscillation damping with supplementary control loops. This paper creates a 5% wind power penetration simulation scenario based on the 16 000-bus EI system dynamic model and developed the user-defined wind electrical control model in PSS (R) E that incorporates additional frequency regulation and oscillation damping control loops. We evaluated the potential contributions of variable-speed wind generations to the EI system frequency regulation and oscillation damping, and simulation results demonstrate that current and future penetrations of wind power are promising in the EI system frequency regulation and oscillation damping.

17 WIND ENERGY↗
NASA NTRS1996

Robust Stabilization of Uncertain Systems Based on Energy Dissipation Concepts

Robust stability conditions obtained through generalization of the notion of energy dissipation in physical systems are discussed in this report. Linear time-invariant (LTI) systems which dissipate energy corresponding to quadratic power functions are characterized in the time-domain and the frequency-domain, in terms of linear matrix inequalities (LMls) and algebraic Riccati equations (ARE's). A novel characterization of strictly dissipative LTI systems is introduced in this report. Sufficient conditions in terms of dissipativity and strict dissipativity are presented for (1) stability of the feedback interconnection of dissipative LTI systems, (2) stability of dissipative LTI systems with memoryless feedback nonlinearities, and (3) quadratic stability of uncertain linear systems. It is demonstrated that the framework of dissipative LTI systems investigated in this report unifies and extends small gain, passivity, and sector conditions for stability. Techniques for selecting power functions for characterization of uncertain plants and robust controller synthesis based on these stability results are introduced. A spring-mass-damper example is used to illustrate the application of these methods for robust controller synthesis.

Gupta, Sandeep↗
DOE OSTI2014

Damage Spreading in Spatial and Small-world Random Boolean Networks

The study of the response of complex dynamical social, biological, or technological networks to external perturbations has numerous applications. Random Boolean Networks (RBNs) are commonly used a simple generic model for certain dynamics of complex systems. Traditionally, RBNs are interconnected randomly and without considering any spatial extension and arrangement of the links and nodes. However, most real-world networks are spatially extended and arranged with regular, power-law, small-world, or other non-random connections. Here we explore the RBN network topology between extreme local connections, random small-world, and pure random networks, and study the damage spreading with small perturbations. We find that spatially local connections change the scaling of the relevant component at very low connectivities ($\bar{K} \ll 1$) and that the critical connectivity of stability $K_s$ changes compared to random networks. At higher $\bar{K}$, this scaling remains unchanged. We also show that the relevant component of spatially local networks scales with a power-law as the system size N increases, but with a different exponent for local and small-world networks. The scaling behaviors are obtained by finite-size scaling. We further investigate the wiring cost of the networks. From an engineering perspective, our new findings provide the key design trade-offs between damage spreading (robustness), the network's wiring cost, and the network's communication characteristics.

Lu, Qiming↗
DOE OSTI2019

An Interconnected Channel-Like Framework as Host for Lithium Metal Composite Anodes

Lithium (Li) metal anodes have long been counted on to meet the increasing demand for high energy, high–power rechargeable battery systems but they have been plagued by uncontrollable plating, unstable solid electrolyte interphase (SEI) formation, and the resulting low Coulombic efficiency. These problems are even aggravated under commercial levels of current density and areal capacity testing conditions. In this work, the channel–like structure of a carbonized eggplant (EP) as a stable “host” for Li metal melt infusion, is utilized. With further interphase modification of lithium fluoride (LiF), the as–formed EP–LiF composite anode maintains ≈90% Li metal theoretical capacity and can successfully suppress dendrite growth and volume fluctuation during cycling. EP–LiF offers much improved symmetric cell and full–cell cycling performance with lower and more stable overpotential under various areal capacity and elevated rate capability. Furthermore, carbonized EP serves as a light–weight high–performance current collector, achieving an average Coulombic efficiency ≈99.1% in ether–based electrolytes with 2.2 mAh cm –2 cycling areal capacity. Furthermore, the natural structure of carbonized EP will inspire further artificial designs of electrode frameworks for both Li anode and sulfur cathodes, enabling promising candidates for next–generation high–energy density batteries.

25 ENERGY STORAGE↗
NASA NTRS1979

Voyager 1 encounter with the Jovian system

An overview of the Voyager 1 encounter with Jupiter is presented. Voyager conducted close range measurements of the atmosphere, satellites and magnetosphere of Jupiter from January 6, 1979 to April 13, 1979, coming as close as 348,890 km to the planet. The three-axis stabilized spacecraft carries radioisotope thermoelectric generators providing 445 W of power to the instruments and transmitters and makes use of an X-band telemetry rate of up to 115.2 kbit/sec, a scan platform providing pointing control of 0.15 deg/axis for the instruments carried on it, and three interconnected computer systems. The trajectory of Voyager through the Galilean satellites is illustrated, noting that the trajectory allows for periods of sun and earth occultation, south polar passage by Io, close encounters with Ganymede and Callisto and earth-Jupiter communications distances supporting 21 to 22 h of maximum data rates daily. Highlights of the results of the investigations are presented.

Stone, E. C.↗
DOE OSTI2026

Mitigating Data Center Impact on Grid Stability: A Coordinated Control Strategy Using Verrus StabiliGrid Architecture

Large data centers, which now represent a significant and growing share of the total U.S. grid load, can inadvertently destabilize the electrical grid when they disconnect simultaneously during brief voltage disturbances. The July 10, 2024, Eastern Interconnection incident, in which a sub-100-millisecond transmission fault triggered the cascading loss of approximately 1,500 MW of data center load, illustrates this vulnerability. While commercial battery energy storage systems (BESS) deployed in data centers provide device-level fault ride-through per IEEE 1547, they lack coordination with facility protection logic and uninterruptible power supplies (UPS), limiting their effectiveness as grid-stabilizing assets. This report presents the Verrus StabiliGrid architecture, a coordinated control framework that integrates BESS, UPS, and point-of-interconnection (POI) protection settings to enable data centers to ride through both undervoltage and overvoltage grid contingencies without disconnecting. The four-step strategy encompasses: (1) high-resolution power quality monitoring to detect the grid state during events such as undervoltage, overvoltage, underfrequency, and overfrequency; (2) POI protection settings that allow for extended ride-through and grid-connected operation during grid contingencies; (3) grid state-driven autonomous dispatch of assets to improve grid resilience by reducing power draw during undervoltage or absorbing more power during overvoltage events; and (4) coordinated post-recovery dispatch of data center assets to restore firm load to pre-contingency levels. Validated through controller-hardware-in-the-loop (C-HIL) simulations at the National Laboratory of the Rockies, results show grid import restoration to pre-fault levels within 100 milliseconds of voltage recovery. This work advances the ability of data centers to transition from passive, disturbance-sensitive loads to active participants in grid stability, a capability increasingly required by emerging NERC and ERCOT regulatory frameworks.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1984

Analytical Models

A system-level design and analysis model was developed. This model was conceived to have several key elements: a solar pond thermodynamic performance model, a power generation subsystem model, and an economic analysis element. The basic approach was to create these elements or modules and refine them on an individual basis yet retain the capability to easily couple them into a full system design model. This building block approach allows for maximum flexibility and substitution of refined descriptions as the technology develops. A general overview of interconnecting these subsystem models is presented. The primary program control element will perform the administrative functions of data input, data output, information storage and transfer, and sequential calling of the subsystem models. From the point of view of the requirements of a system design model, a power conversion subsystem model was developed. The goal of the effort was a preliminary subsystem model compatible with the solar pond subsystem model so that a first order system simulation analysis could be performed.

Source record↗
DOE OSTI2019

Quantifying Transmission Fault Voltage Influence and its Potential Impact on Distributed Energy Resources

With increasing shares of distributed energy resources (DERs) on the electric grid, the power system is transitioning from having fewer large generators with relatively simple dynamics to many small generators with aggregate responses to system disturbances that are difficult to predict. In particular, voltage fluctuations might cause large losses of generation via DER operation/interconnection compliance. To understand orchestral DER dynamics, a first step is to determine the influence of a disturbance on the overall bulk power system. This work introduces metrics that allow for the classification and comparison of a variety of system faults with respect to their influences on voltage profiles. These metrics are applied to standardized fault simulations on the Western Interconnection Paths with a full-scale Positive Sequence Load Flow model. The results are presented with a highlight on Path 61, which has the potential for DER generation reduction exceeding the current credible contingency of a double Palo Verde loss.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRSDate not supplied

Impedance Measurements of Motor Drives and Supplies in NASA NEAT Facility

Many electrified aircraft configurations consist of a number of power components operating on the same shared electrical bus. Understanding the impedance performance of electrical loads and sources is key to understanding, and designing for, acceptable overall vehicle power quality and power system stability. This paper discusses impedance measurements made on the NASA Electric Aircraft Testbed (NEAT) Electrical Power System (EPS) at NASA Glenn Research Center. First, an overall discussion of the NEAT facility configuration during testing is presented; then details of the impedance measurement approach and the various testing configurations are discussed. Next, input impedance measurements at NEAT, including sources (DC supplies) and loads (multiple motor drives, electric machines, and resistive load banks, with long interconnecting cable leads), are performed under a number of conditions, and results, including load model comparisons and stability analysis, are presented and discussed.

electrified aircraft propulsion↗
DOE OSTI2018

Uniform redundancy allocation maximizes the robustness of flow networks against cascading failures

We study the robustness of flow networks against cascading failures under a partial load redistribution model. In particular, we consider a flow network of N lines with initial loads L 1 ,...,L N and free spaces (i.e., redundant space) S 1 ,...,S N that are independent and identically distributed with joint distribution P LS (x,y) = P[L ≤ x, S ≤ y]. The capacity C i is the maximum load allowed on line i and is given by C i = L i + S i . Furthermore, when a line fails due to overloading, it is removed from the system and (1 – ε) fraction of the load it was carrying is redistributed equally among all remaining lines in the system. The rest (i.e., ε fraction) of the load is assumed to be lost or absorbed, e.g., due to advanced circuitry disconnecting overloaded power lines or an interconnected network or material absorbing a fraction of the flow from overloaded lines. We analyze the robustness of this flow network against random attacks that remove a p fraction of the lines. Our contributions include (i) deriving the final fraction of alive lines n ∞ (p,ε) for all p,εϵ(0,1) and confirming the results via extensive simulations; (ii) showing that partial redistribution might lead to (depending on the parameter 0 < ε ≤ 1) the order of transition at the critical attack size p* changing from first to second-order; and (iii) proving analytically that flow networks achieve maximum robustness [quantified by the area ∫$^{1}_{0}$ n ∞ (p,ε)dp] when all lines have the same free space regardless of their initial load. The optimality of equal free-space allocation is also confirmed on real-world data from the UK National Power Grid.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1973

High bit rate mass data storage device

The HDDR-II mass data storage system consists of a Leach MTR 7114 recorder reproducer, a wire wrapped, integrated circuit flat plane and necessary power supplies for the flat plane. These units, with interconnecting cables and control panel are enclosed in a common housing mounted on casters. The electronics used in the HDDR-II double density decoding and encoding techniques are described.

Source record↗