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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Maui Smart Grid Demonstration Project Managing Distribution System Resources for Improved Service Quality and Reliability, Transmission Congestion Relief, and Grid Support Functions

The Maui Smart Grid Project (MSGP) is under the leadership of the Hawaii Natural Energy Institute (HNEI) of the University of Hawaii at Manoa. The project team includes Maui Electric Company, Ltd. (MECO), Hawaiian Electric Company, Inc. (HECO), Sentech (a division of SRA International, Inc.), Silver Spring Networks (SSN), Alstom Grid, Maui Economic Development Board (MEDB), University of Hawaii-Maui College (UHMC), and the County of Maui. MSGP was supported by the U.S. Department of Energy (DOE) under Cooperative Agreement Number DE-FC26-08NT02871, with approximately 50% co-funding supplied by MECO. The project was designed to develop and demonstrate an integrated monitoring, communications, database, applications, and decision support solution that aggregates renewable energy (RE), other distributed generation (DG), energy storage, and demand response technologies in a distribution system to achieve both distribution and transmission-level benefits. The application of these new technologies and procedures will increase MECO’s visibility into system conditions, with the expected benefits of enabling more renewable energy resources to be integrated into the grid, improving service quality, increasing overall reliability of the power system, and ultimately reducing costs to both MECO and its customers.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2015

Electric Power quality Analysis in research reactor: Impacts on nuclear safety assessment and electrical distribution reliability

The increased requirements on supervision, control, and performance in modern power systems make power quality monitoring a common practise for utilities. Large databases are created and automatic processing of the data is required for fast and effective use of the available information. Aim of the work presented in this paper is the development of tools for analysis of monitoring power quality data and in particular measurements of voltage and currents in various level of electrical power distribution. The study is extended to evaluate the reliability of the electrical system in nuclear plant. Power Quality is a measure of how well a system supports reliable operation of its loads. A power disturbance or event can involve voltage, current, or frequency. Power disturbances can originate in consumer power systems, consumer loads, or the utility. The effect of power quality problems is the loss power supply leading to severe damage to equipments. So, we try to track and improve system reliability. The assessment can be focused on the study of impact of short circuits on the system, harmonics distortion, power factor improvement and effects of transient disturbances on the Electrical System during motor starting and power system fault conditions. We focus also on the review of the Electrical System design against the Nuclear Directorate Safety Assessment principles, including those extended during the last Fukushima nuclear accident. The simplified configuration of the required system can be extended from this simple scheme. To achieve these studies, we have used a demo ETAP power station software for several simulations. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

The effect of the NERC CIP standards on the reliability of the North American Bulk Electric System

Considerable money and effort has been expended by generation, transmission, and distribution entities in North America to implement the North American Electric Reliability Corporation (NERC) Critical Infrastructure Protection (CIP) standards for the bulk electric system. Assumptions have been made that as a result of the implementation of the standards, the grid is more cyber secure than it was pre-NERC CIP, but are there data supporting these claims, or only speculation? Has the implementation of the standards had an effect on the grid? Furthermore, developing a research study to address these and other questions provided surprising results.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Practical Implementation of Synchrophasor Based Real-Time Contingency Analysis

Synchrophasor technology is increasingly accepted and adopted by the power industry. Linear State Estimator (LSE) is a recent development in the synchrophasor industry, and has been integrated and deployed at control centers, providing improved coverage and greater reliability from synchrophasor systems. This paper describes a first-of-a-kind synchrophasor based real-time contingency analysis (RTCA), which takes the LSE solved case as input, and then solves the what-if cases to provide timely information about impending grid problems to system operators. Test results on IEEE 39 bus and 300 bus system demonstrate the accuracy of the method for solving the RTCA problem using synchrophasor data. With this the synchrophasor measurement system provides an independent real-time monitoring and operation system which utilizes PMU data alone.

Nayak, Neeraj↗
DOE OSTI2024

An Integrated Assessment of a G3 GMD Event on Large-Scale Power Grids: From Magnetometer Data to Geomagnetically Induced Current Analysis

Solar activities can cause geomagnetic disturbances (GMDs) that give rise to geomagnetically induced currents (GICs) which may compromise the reliability of the power system. In order to build more reliable models representing GMD interactions with the power grid, the power system’s detailed electrical model must be considered along with fluctuations in the earth’s magnetic and induced surface electric fields. Here, this study investigates the impact of incorporating spatially varying magnetic fields into surface electric field models on GMD risk metrics. A spatially independent magnetic field model and a spatially varying model are compared through simulations. To perform this analysis, the earth’s magnetic field disturbances are transformed into surface electric fields using respective one-dimensional earth conductivity models. Then, the modeling impact of these electric fields is studied using a 2,000-bus grid for Texas and a 25,000-bus grid for the northeast and mid- Atlantic regions of the United States. Simulation results reveal that the inclusion of spatially varying magnetic fields results in considerable differences in GMD risk metrics, highlighting the importance of accounting for spatial variability when assessing GMD risks in the power system.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

A Methodology for Quantifying Reliability Benefits From Improved Solar Power Forecasting in Multi-Timescale Power System Operations

Solar power forecasting improvements are mainly evaluated by statistical and economic metrics, and the practical reliability benefits of these forecasting enhancements have not yet been well quantified. This paper aims to quantify reliability benefits from solar power forecasting improvements. To systematically analyze the relationship between solar power forecasting improvements and reliability performance in power system operations, an expected synthetic reliability (ESR) metric is proposed to integrate state-of-the-art independent reliability metrics. The absolute value and standard deviation of area control errors (ACE), and the North American Electric Reliability Corporation Control Performance Standard 2 (CPS2) score are calculated through the multi-timescale scheduling simulation, including the day-ahead unit commitment (DU), real-time unit commitment (RU), real-time economic dispatch (RE), automatic generation control (AGC) sub-models. The absolute area control error in energy (AACEE), CPS2 violations, CPS2 score, and standard deviation of the raw ACE are all calculated and combined as the ESR metric. Numerical simulations show that the reliability benefits of multi-timescale power system operations are significantly increased due to the improved solar power forecasts.

24 POWER TRANSMISSION AND DISTRIBUTION↗
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 OSTI2018

Stochastic correlation analysis to rank the impact of intermittent wind generation on unreliability margins of power systems

Power systems are vulnerable to extreme contingencies (like an outage of a major generating substation or transmission line) that can cause significant generation and load loss and can lead to further cascading outages of other transmission facilities and generators in the system. Power systems operators take time-ahead actions (real time to day ahead) actions based on forecasted data as well as telemetry. However, there is a probability of extreme swings in wind generation that can push the power system that is already close to system boundaries into unreliable states. Increasing penetration on wind generation and uncertainties in short term forecast can move the system into operational states that can violate N-1 reliability criteria. While the power system planning accounts for worst case analyses to mitigate such emergencies, it is necessary to understand the spatial and temporal correlation of load buses with intermittent wind generation. The ranking of wind generators based on stochastic correlation to unreliability margins of load buses provides an insight of system vulnerabilities that can be corrected by appropriate emergency controls. A Monte-Carlo simulation of wind uncertainty forecast is performed to identify the probability distributions of unreliability margins. Ranking of wind generators is performed based on stochastic correlation analysis of the wind power generated and the load losses at the buses. This helps in not only identifying weak buses in the power system but also in identifying the vulnerable wind locations to plan for system reinforcements. Power system modeling and hybrid simulation to calculate unreliability margins are performed using DCAT and demonstrated on the 32-bus Nordic test system.

generators, wind forecasting, wind power generatio↗
DOE OSTI2017

Characterizing cyber tools for monitoring power grid systems: what information is available and who needs it?

Abstract—The power grid is a complex, interconnected system that requires the coordination of multiple entities ensure the reliability of the system. System operators must be aware of the impacts of various natural and man-made contingencies through telemetry from their control systems, and they must also be aware of the integrity and availability of the cyber assets on their systems. A team of researchers from PNNL and INL have conducted a series of observations and interviews at power utilities to identify what information needs to be available for both control room dispatchers and cyber security analysts to maintain situation awareness of cyber security to effectively monitor the cyber assets on utility control systems. The researchers interviewed and observed control room dispatchers and spoke with regional control system engineers and cyber security analysts to define the context in which such information would be used. The results of this work will inform the design of a tool that will enhance cyber situation awareness and help facilitate effective communication between the various roles and organizations with utility and other regional authorities during contingencies. Index Terms—

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Power System Event Identification Based on Deep Neural Network With Information Loading

Online power system event identification and classification are crucial to enhancing the reliability of transmission systems. In this study, we develop a deep neural network (DNN) based approach to identify and classify power system events by leveraging real-world measurements from hundreds of phasor measurement units (PMUs) and labels from thousands of events. Two innovative designs are embedded into the baseline model built on convolutional neural networks (CNNs) to improve the event classification accuracy. First, we propose a graph signal processing based PMU sorting algorithm to improve the learning efficiency of CNNs. Second, we deploy information loading based regularization to strike the right balance between memorization and generalization for the DNN. Numerical results based on real-world dataset from the Eastern Interconnection of the U.S power transmission grid show that the combination of PMU based sorting and the information loading based regularization techniques help the proposed DNN approach achieve highly accurate event identification and classification results.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2014

Demonstration of a Variable Phase Turbine Power System for Low Temperature Geothermal Resources

A variable phase turbine assembly will be designed and manufactured having a turbine, operable with transcritical, two-phase or vapor flow, and a generator – on the same shaft supported by process lubricated bearings. The assembly will be hermetically sealed and the generator cooled by the refrigerant. A compact plate-fin heat exchanger or tube and shell heat exchanger will be used to transfer heat from the geothermal fluid to the refrigerant. The demonstration turbine will be operated separately with two-phase flow and with vapor flow to demonstrate performance and applicability to the entire range of low temperature geothermal resources. The vapor leaving the turbine is condensed in a plate-fin refrigerant condenser. The heat exchanger, variable phase turbine assembly and condenser are all mounted on single skids to enable factory assembly and checkout and minimize installation costs. The system will be demonstrated using low temperature (237F) well flow from an existing large geothermal field. The net power generated, 1 megawatt, will be fed into the existing power system at the demonstration site. The system will demonstrate reliable generation of inexpensive power from low temperature resources. The system will be designed for mass manufacturing and factory assembly and should cost less than $\$$1,200/kWe installed, when manufactured in large quantities. The estimated cost of power for 300F resources is predicted to be less than 5 cents/kWh. This should enable a substantial increase in power generated from low temperature geothermal resources.

15 GEOTHERMAL ENERGY↗
DOE OSTI2019

A Study of the Impact of Reduced Inertia in Power Systems

Inertia in power systems plays an important role in maintaining the stability and reliability of the system by counteracting changes in frequency. However, the traditional sources of synchronous generation are being displaced by renewable resources, which often have no inherent inertia. This paper investigates the impact of reduced system inertia on several aspects of the dynamic stability of power systems, such as angular stability, primary frequency response, and oscillatory modes. This study is performed on a large-scale 2000 bus synthetic Texas model by selectively replacing synchronous generators with inverter-based generation resources. This paper also compares the analysis results obtained by the above-mentioned inertia-reduction approach of renewable integration with another approach in which the inertia constant of all synchronous generators is decreased. This paper demonstrates that only reducing the inertia of all synchronous generators in a system does not provide an accurate analysis of the challenges associated with the reduced system inertia caused by renewable integration.

System Inertia, Angular stability, System Inertial↗
DOE OSTI2015

Sources of Operational Flexibility, Greening the Grid

Changes in electricity demand and generation must be constantly balanced to maintain power system stability and reliability. Operational flexibility refers to the ability of a power system to respond to these changes. Power systems are designed and operated to efficiently manage variability and uncertainty in electricity demand and resource availability. Variable renewable energy (VRE) increases this inherent variability and uncertainty, and thus increases the need for flexibility. Systems with significant variability and uncertainty require flexible generators that can rapidly change output, operate efficiently at lower outputs, and operate for short durations. This flexibility in turn can reduce the need to curtail (decrease the output of) solar and wind generation; improve investor confidence in VRE and revenue streams; decrease the risk of negative market pricing (which results when conventional generators cannot turn down to low outputs during times of high VRE output); and reduce environmental impacts by increasing system efficiency and maximizing the utilization of VRE.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2023

Uncertainty Error Modeling for Non-Linear State Estimation With Unsynchronized SCADA and µPMU Measurements

Distribution systems of the future smart grid require enhancements to the reliability of distribution system state estimation (DSSE) in the face of low measurement redundancy, unsynchronized measurements, and dynamic load profiles. Micro phasor measurement units (µPMUs) facilitate co-synchronized measurements with high granularity, albeit at an often prohibitively expensive installation cost. Supervisory control and data acquisition (SCADA) measurements can supplement µPMU data, although they are received at a slower sampling rate. Further complicating matters is the uncertainty associated with load dynamics and unsynchronized measurements–not only are the SCADA and µPMU measurements not synchronized with each other, but the SCADA measurements themselves are received at different time intervals with respect to one another. This paper proposes a non-linear state estimation framework which models dynamic load uncertainty error by updating the variances of the unsynchronized measurements, leading to a time-varying system of weights in the weighted least squares state estimator. Case studies are performed on the 33-Bus Distribution System in MATPOWER, using Ornstein–Uhlenbeck stochastic processes to simulate dynamic load conditions.

Cooper, Austin↗
DOE OSTI2015

Enabling Situation Awareness Under High Levels of Automation: Results From An Experimental Study

The Department of Energy’s Advanced Reactor Technologies (ART) program sponsors research, development and deployment activities through its Next Generation Nuclear Plant, Advanced Reactor Concepts, and Advanced Small Modular Reactor (aSMR) programs to promote safety, technical, economical, and environmental advancements of innovative Generation IV nuclear energy technologies. The Human Automation Collaboration (HAC) research project is located under the aSMR program, which identifies developing advanced instrumentation and controls and human-machine interfaces as one of four key research areas. New nuclear plants are expected to employ significantly more advanced technology than the systems in the current reactor fleet as well as utilize automation to a greater extent. However, advancing technology and increasing automation does not necessarily imply improved efficiency and safety of the plant. Instead, a number of concerns about how these technologies will affect human performance and the overall safety of the plant need to be addressed. More specifically, it is important to investigate how the operator and the automation work as a team to ensure effective and safe plant operation, also known as the human-automation collaboration (HAC). The HAC project at INL, investigates collaboration methods between a system’s automation and human operators and how that collaboration impacts the performance and reliability of overall system performance. Some well documented human performance issues associated with typical human automation collaboration methods include reduced operator situation awareness (SA), complacency, and over reliance on the system automation (Endsley, 1995, 1996, 1997; Endsley & Kaber, 1999; Kaber & Endsley, 1997, 2004; Parasuraman et al., 2000; Sheridan, 2002; Wickens & Hollands, 2000; Wright & Kaber, 2005). The HAC research effort addresses how to best design the collaboration between the operators and the automated systems in a manner that has the greatest positive impact on overall plant performance and reliability, hence addressing many of the documented issues. The ultimate goal of the HAC research effort is to develop design guidance that supports optimal interaction between humans and automated systems.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2014

Non-linear dynamic characteristics and optimal control of giant magnetostrictive film subjected to in-plane stochastic excitation

The non-linear dynamic characteristics and optimal control of a giant magnetostrictive film (GMF) subjected to in-plane stochastic excitation were studied. Non-linear differential items were introduced to interpret the hysteretic phenomena of the GMF, and the non-linear dynamic model of the GMF subjected to in-plane stochastic excitation was developed. The stochastic stability was analysed, and the probability density function was obtained. The condition of stochastic Hopf bifurcation and noise-induced chaotic response were determined, and the fractal boundary of the system's safe basin was provided. The reliability function was solved from the backward Kolmogorov equation, and an optimal control strategy was proposed in the stochastic dynamic programming method. Numerical simulation shows that the system stability varies with the parameters, and stochastic Hopf bifurcation and chaos appear in the process; the area of the safe basin decreases when the noise intensifies, and the boundary of the safe basin becomes fractal; the system reliability improved through stochastic optimal control. Finally, the theoretical and numerical results were proved by experiments. The results are helpful in the engineering applications of GMF.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Space Vehicle Reliability Modeling in DIORAMA

When modeling system performance of space based detection systems it is important to consider spacecraft reliability. As space vehicles age the components become prone to failure for a variety of reasons such as radiation damage. Additionally, some vehicles may lose the ability to maneuver once they exhaust fuel supplies. Typically failure is divided into two categories: engineering mistakes and technology surprise. This document will report on a method of simulating space vehicle reliability in the DIORAMA framework.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Reliable voltage scaled links for compressed data

Systems, apparatuses, and methods for reliably transmitting data over voltage scaled links are disclosed. A computing system includes at least first and second devices connected via a link. In one implementation, if a data block can be compressed to less than or equal to half the original size of the data block, then the data block is compressed and sent on the link in a single clock cycle rather than two clock cycles. If the data block cannot be compressed to half the original size, but if the data block can be compressed enough to include error correction code (ECC) bits without exceeding the original size, then ECC bits are added to the compressed block which is sent on the link at a reduced voltage. The ECC bits help to correct for any errors that are generated as a result of operating the link at the reduced voltage.

42 ENGINEERING↗