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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Transmission-Distribution Dynamic Co-Simulation of Electric Vehicles Providing Grid Frequency Response: Preprint

This paper investigates the impacts of electric vehicles (EVs) on power system frequency regulation based on an open-source transmission-and-distribution (T&D) dynamic co-simulation framework. The development of a EV dynamic model based on appropriate WECC dynamic model is introduced first, then the T&D dynamic co-simulation platform is described. The advantage of the overall platform is that DERs such as distributed photovoltaic (DPV) and EV are modeled explicitly in both transmission and distribution simulators for frequency dynamics and voltage, respectively. In the case studies, EVs frequency responses (i.e., primary and/or secondary) are simulated after the system is exposed to N-1 contingency such as a generation trip. Various EV frequency regulation participation strategies are investigated as well to study their impacts on system frequency response. The studies shows that EVs have potential capability to provide effective frequency regulation services.

electric vehicle↗
NASA NTRS1972

Magnitude error bounds for sampled-data frequency response obtained from the truncation of an infinite series, and compensator improvement program

The frequency response method of analyzing control system performance is discussed, and the difficulty of obtaining the sampled frequency response of the continuous system is considered. An upper bound magnitude error equation is obtained which yields reasonable estimates of the actual error. Finalization of the compensator improvement program is also reported, and the program was used to design compensators for Saturn 5/S1-C dry workshop and Saturn 5/S1-C Skylab.

Mitchell, J. R.↗
NASA NTRS1947

Frequency-response method for determination of dynamic stability characteristics of airplanes with automatic controls

A frequency-response method for determining the critical control-gearing and hunting oscillations of airplanes with automatic pilots is presented. The method is graphical and has several advantages over the standard numerical procedure based on Routh's discriminant. The chief advantage of the method is that direct use can be made of the measured response characteristics of the automatic pilot. This feature is especially useful in determining the existence, amplitude, and frequency of the hunting oscillations that may be present when the automatic pilot has nonlinear dynamic characteristics. Several examples are worked out to illustrate the application of the frequency-response method in determining the effect of automatic-pilot lag or lead on critical control gearing and in determining the amplitude and frequency hunting. It is shown that the method may be applied to the case of a control geared to airplane motions about two axes.

Greenberg, Harry↗
NASA NTRS2016

Aircraft Fault Detection Using Real-Time Frequency Response Estimation

A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

Grauer, Jared A.↗
NASA NTRS1951

Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine are presented. These data were obtained by subjecting the engine to sinusoidal variations of fuel flow and propeller-blade-angle inputs. Correlation is made between these experimental data and analytical frequency-response characteristics obtained from a linear differential equation derived from steady-state torque-speed relations.

Taylor, Burt L , III↗
DOE OSTI2018

Frequency Response Study of a U.S. Western Interconnection under Extra-High Photovoltaic Generation Penetrations: Preprint

Increasing penetration levels of solar photovoltaic (PV) and the reduced inertia of inverter-based generation technologies have caught the attention of the electric power industry and academia in the United States. This paper conducts a comprehensive frequency response study of the Western Interconnection under high penetration levels of PV, which are up to 80% at the interconnection level and 100% at the regional level. Based on the 2022 Light Spring case, PV has been projected by areas for four PV penetration levels based on collected realistic PV distribution information. The overall system frequency response has been analyzed under different scenarios. In particular, the 100% regional PV penetration case has been developed to reveal local frequency issues in the Western Interconnection. The potential of using existing resources to improve frequency response has also been studied. New insights in this paper address the implications of the rapid deployment of solar generation in the Western Interconnection.

14 SOLAR ENERGY↗
NASA NTRS1990

Frequency response of electrochemical cells

The main objective was to examine the feasibility of using frequency response techniques (1) as a tool in destructive physical analysis of batteries, particularly for estimating electrode structural parameters such as specific area, porosity, and tortuosity and (2) as a non-destructive testing technique for obtaining information such as state of charge and acceptability for space flight. The phenomena that contribute to the frequency response of an electrode include: (1) double layer capacitance; (2) Faradaic reaction resistance; (3) mass transfer of Warburg impedance; and (4) ohmic solution resistance. Nickel cadmium cells were investigated in solutions of KOH. A significant amount of data was acquired. Quantitative data analysis, using the developed software, is planned for the future.

Thomas, Daniel L.↗
DOE OSTI2022

Impact of Quaternary Pumped Storage Hydropower on Frequency Response of U.S. Western Interconnection with High Renewable Penetrations

As renewable penetration increases in the United States, maintaining stability and reliability of low-inertia power grid by providing sufficient frequency control capability becomes a challenge. Advanced pumped storage hydro technologies (APSH) will be expected to play an important role for future grid as not only an energy supplier, but also as an ancillary services provider. This paper studies the impact of using quaternary pumped storage hydropower (Q-PSH), as one of the newly proposed APSH technology, to provide primary frequency response. To quantify the impact of Q-PSH on frequency response of the U.S. Western Interconnection, a user-defined dynamic model of Q-PSH is developed on the GE Positive Sequence Load Flow (PSLF) platform and is implemented in a set of detailed U.S. Western Electricity Coordination Council (WECC) planning cases in which renewable penetration levels are 20%, 40%, 60% and 80%. Simulation results show that Q-PSH can help improve frequency nadir and settling frequency comparing to the conventional PSH.

frequency response↗
DOE OSTI2022

Impact of Quaternary-Pumped Storage Hydropower on Frequency Response of U.S. Western Interconnection with High Renewable Penetrations: Preprint

As renewable penetration increases in the United States, maintaining stability and reliability of low-inertia power grid by providing sufficient frequency control capability becomes a challenge. Advanced pumped storage hydro technologies (APSH) will be expected to play an important role for future grid as not only an energy supplier, but also as an ancillary services provider. This paper studies the impact of using quaternary pumped storage hydropower (Q-PSH), as one of the newly proposed APSH technology, to provide primary frequency response. To quantify the impact of Q-PSH on frequency response of the U.S. Western Interconnection, a user-defined dynamic model of Q-PSH is developed on the GE Positive Sequence Load Flow (PSLF) platform and is implemented in a set of detailed U.S. Western Electricity Coordination Council (WECC) planning cases in which renewable penetration levels are 20%, 40%, 60% and 80%. Simulation results show that Q-PSH can help improve frequency nadir and settling frequency comparing to the conventional PSH.

frequency response↗
DOE OSTI2019

A FREQUENCY RESPONSE APPROACH TO MODEL VALIDATION FOR THE COMPACT INTEGRAL EFFECTS TEST FACILITY IN TRANSFORM

One of the key challenges to licensing new reactor designs is validating the integral transient response models of a novel system. This work used a frequency response approach for model validation of the Compact Integral Effects Test (CIET) facility at the University of California, Berkeley. This facility was built as a scaled integral effects test for verifying transient modeling tools for fluoride-salt-cooled hightemperature reactors using Dowtherm A as a simulant fluid for molten salt. The dynamic system model of CIET was created using the Modelica-based TRANSFORM tool developed by Oak Ridge National Laboratory (ORNL). Analysis of the model’s performance as compared with experimental results indicates good agreement under both steady-state and transient conditions. This paper describes the Modelica model creation process using TRANSFORM and the modeling assumptions and methods for matching dynamic behavior with frequency response data. Results, analysis, and a discussion of future work are also presented.

De wet, Dane↗
NASA NTRS1967

Computer program for network synthesis by frequency response fit

Computer program synthesizes a passive network by minimizing the difference in desired and actual frequency response. The program solves for the critical points of the error function /weighted least squares fit between calculated and desired frequency response/ by the multivariable Newton-Raphson method with components constrained to an admissible region.

Green, S.↗
NASA NTRS1991

Frequency response calibration of recess-mounted pressure transducers

A technique is described for measuring the frequency response of pressure transducers mounted inside a model, where a narrow pipette leads to an orifice at the surface. An acoustic driver is mounted to a small chamber which has an opening at the opposite end with an O-ring seal to place over the orifice. A 3.18 mm (1/8 inch) reference microphone is mounted to one side of the chamber. The acoustic driver receives an input of white noise, and the transducer and reference microphone outputs are compared to obtain the frequency response of the pressure transducer. Selected results are presented in the form of power spectra for both the transducer and the reference, as well as the amplitude variation and phase shift between the two signals as a function of frequency. The effect of pipette length and the use of this technique for identifying both blocked orifices and faulty transducers are described.

Marcolini, M. A.↗
DOE OSTI2018

Fast Primary Frequency Response using Coordinated DER and Flexible Loads: Framework and Residential-scale Demonstration

Methods for supporting grid frequency stabilization using widespread flexible load and DER are becoming essential as the portion of synchronous generation decreases. This article develops a framework for providing fast primary frequency response that leverages deferrable loads and DER coordinated using high-speed measurements in real time to ensure that local objectives are met. The framework is demonstrated in a residential-scale experiment with four household appliances and an inverter. The effectiveness of an example load management algorithm is demonstrated using three underfrequency anomaly test cases. The experimental data corroborates that in all cases, the entire coordinated response, from detection and measurement of a frequency anomaly to completed coordinated net-load response, is completed within 143 ms (~8.5 cycles).

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Fast Primary Frequency Response Using Coordinated DER and Flexible Loads: Framework and Residential-Scale Demonstration: Preprint

Methods for supporting grid frequency stabilization using widespread flexible load and DER are becoming essential as the portion of synchronous generation decreases. This article develops a framework for providing fast primary frequency response that leverages deferrable loads and DER coordinated using high-speed measurements in real time to ensure that local objectives are met. The framework is demonstrated in a residential-scale experiment with four household appliances and an inverter. The effectiveness of an example load management algorithm is demonstrated using three underfrequency anomaly test cases. The experimental data corroborates that in all cases, the entire coordinated response, from detection and measurement of a frequency anomaly to completed coordinated net-load response, is completed within 143 ms (about 8.5 cycles).

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1985

Rapid estimation of frequency response functions by close-range photogrammetry

The accuracy of a rapid method which estimates the frequency response function from stereoscopic dynamic data is computed. It is shown that reversal of the order of the operations of coordinate transformation and Fourier transformation, which provides a significant increase in computational speed, introduces error. A portion of the error, proportional to the perturbation components normal to the camera focal planes, cannot be eliminated. The remaining error may be eliminated by proper scaling of frequency data prior to coordinate transformation. Methods are developed for least squares estimation of the full 3x3 frequency response matrix for a three dimensional structure.

Tripp, J. S.↗