Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Electrical and Electronics (10)
- Controls and Control Theory (7)
- Physical Sciences and Mathematics (5)
- Signal Processing (5)
- Computer Sciences (3)
-
- Mechanical Engineering (3)
- Aerospace Engineering (2)
- Automotive Engineering (2)
- Environmental Sciences (2)
- Information Security (2)
- Materials Science and Engineering (2)
- Military Vehicles (2)
- Other Electrical and Computer Engineering (2)
- Systems and Communications (2)
- VLSI and Circuits, Embedded and Hardware Systems (2)
- Aviation (1)
- Aviation Safety and Security (1)
- Civil Engineering (1)
- Civil and Environmental Engineering (1)
- Computer Engineering (1)
- Computer and Systems Architecture (1)
- Data Science (1)
- Earth Sciences (1)
- Electromagnetics and Photonics (1)
- Electronic Devices and Semiconductor Manufacturing (1)
- Engineering Science and Materials (1)
- Geology (1)
- Keyword
-
- Electric Vehicles (4)
- Power Systems (3)
- Artificial intelligence (2)
- Co-simulation (2)
- Degradation Forecasting (2)
-
- Distance protection (2)
- Distribution systems (2)
- Fault (2)
- Inverter-based resources (2)
- Microgrids (2)
- Model Predictive Control (2)
- Power distribution systems (2)
- Power electronics (2)
- Power system protection (2)
- Voltage control (2)
- 7075 aluminum alloy (1)
- Active Cooling (1)
- Active Thermal Control (1)
- Alternating current (1)
- Ammonia (1)
- Atmospheric energy harvesting (1)
- Atmospheric temperature variations (1)
- Aviation application (1)
- BESS (1)
- Battery Degradation (1)
- Battery-free Systems Support (1)
- Batteryless Security (1)
- Batteryless and Energy Harvesting Embedded Systems (1)
- Black-box modeling (1)
- Bus impedance matrix (1)
- Publication
Articles 1 - 30 of 47
Full-Text Articles in Power and Energy
Enhanced Situational Awareness Of Solar Pv Plants For Near Real-Time Planning And Operation In Modern Power Systems, Michael A. Walters
Enhanced Situational Awareness Of Solar Pv Plants For Near Real-Time Planning And Operation In Modern Power Systems, Michael A. Walters
All Theses
Solar photovoltaic (PV) plant development and utilization is increasing worldwide but remains intrinsically challenged by its large dependence on highly variable weather conditions and operating states. This paper presents a framework to leverage three new situational awareness indices (SAIs), namely: weather condition index (WCI) to gauge operational performance based on environmental states, operational complexity index (OCI) to indicate the severity of power generation reductions, and photovoltaic generation index (PVGI) to provide a final determination of the impact on power generation and to bolster situational awareness in planning and operational contexts for solar PV plants. This is accomplished by exploiting the …
Neural-Network-Based Modeling Of Grid-Forming Inverters, Jacob D. Levesque
Neural-Network-Based Modeling Of Grid-Forming Inverters, Jacob D. Levesque
All Theses
Renewable energy production has grown significantly in recent years and continues to expand, resulting in an increasing number of inverter-based resources (IBRs) in the grid. As the number of IBRs in the grid continues to grow, grid-forming (GFM) inverters are becoming increasingly popular due to their ability to regulate voltage and frequency, providing increased grid stability and enabling islanding. As GFM inverters become more widely used in power systems, accurate and efficient models of their behavior are needed for system design purposes.
Emerging advances in neural networks have led to research on computationally efficient neural-network-based (NN-based) modeling approaches for inverters. …
Measurement-Based Dynamic Load Model Parameterization Via A Stacked Long Short-Term Memory - Deep Neural Network, Zach H. Smith
Measurement-Based Dynamic Load Model Parameterization Via A Stacked Long Short-Term Memory - Deep Neural Network, Zach H. Smith
All Theses
Increases in distributed generation and changes to predominate load types in modern power systems are driving the need for updated or newly developed dynamic load models. Accurate load modeling is necessary for transmission planning and operation, post-mortem analysis, and inter-regional transfer studies. The most widely used dynamic load model is the WECC Composite Load (CMLD). The CMLD model is an aggregation of substation impedance, under voltage and frequency controls, dynamic motor loads, and static loads. Parameterizing dynamic load models, especially composite models with high parameter counts like the CMLD, is can be difficult. This work proposes a measurement-based, machine learning …
Thermal Management Of Power Electronic Converters In Electric Motor Drives Using Active Thermal Control And Active Cooling, S M Imrat Rahman
Thermal Management Of Power Electronic Converters In Electric Motor Drives Using Active Thermal Control And Active Cooling, S M Imrat Rahman
All Dissertations
The application of power electronic converters (PEC) in electric vehicles (EVs) has significantly increased due to their enhanced controllability and flexibility. Additionally, Permanent Magnet Synchronous Machines (PMSMs) are favored in EVs for their higher torque, efficiency, performance, and heat dissipation capabilities compared to asynchronous machines. The reliable operation of power converters in PMSM drives is crucial for EV operation, and this is driving interest in developing innovative and sustainable technologies that ensure the safe and reliable functioning of PECs. One of the main challenges in achieving reliable PECs is designing effective thermal management systems to control junction temperature and reduce …
End-To-End Direct Current For Standalone Power Network, Eyad Ahmad Aldarsi
End-To-End Direct Current For Standalone Power Network, Eyad Ahmad Aldarsi
All Dissertations
The primary issue that faces the humanity is climate change and because of that greenhouse gases (GHGs) emissions are rising. The consequences of this issue have emphasized the necessity for replacing the dominant method of electricity generation, which mostly utilizes fossil fuels, to be centered on access to all, green, low-cost, and renewable sources of energy. Currently, photovoltaics (PV) and wind turbines are the two technologies so far that can convert the source of renewable energy, which is produced by sun irradiance and wind respectively, into large-scale electric power that can be distributed into the electricity grid. The work in …
Secure Control And Trust Evaluation Framework For Autonomous Transportation Systems, Grace Muriithi
Secure Control And Trust Evaluation Framework For Autonomous Transportation Systems, Grace Muriithi
All Dissertations
This dissertation advances the cybersecurity of hybrid tracked vehicles (HTVs) and ship power systems (SPSs) by developing innovative cyber-attack models and corresponding defence frameworks. First, we formulate stealthy false-data-injection attacks (FDIAs) on HTV energy-management systems as a partially observable Markov decision process (POMDP) solved via deep reinforcement learning. A novel sniffing-based reward function guides the attacker to covertly degrade battery capacity and energy efficiency, which we evaluate using custom stealth–impact metrics and a sliding-window anomaly detector (Isolation Forest with Dynamic Time Warping). Additionally, we model sophisticated control-layer attacks in HTVs, including reinforcement-learning-optimised replay attacks and denial-of-service (DoS) attacks targeting generator-speed …
Data-Driven Koopman Theory For Transient Stability And Safety Analysis Of Power Systems With Renewable Penetration, Bhagyashree Umathe
Data-Driven Koopman Theory For Transient Stability And Safety Analysis Of Power Systems With Renewable Penetration, Bhagyashree Umathe
All Dissertations
This dissertation presents a novel approach to analyzing and controlling nonlinear systems using the Koopman operator framework and data-driven methods. Nonlinear power systems, characterized by complex behaviors and sensitivity to initial conditions, pose significant challenges for stability and safety assessment, especially during transient events.
The first part of this work focuses on reachability analysis using the spectral properties of the Koopman operator. By leveraging eigenfunctions extracted from sampled trajectory data, the approach computes forward and backward reachable sets efficiently, even in high-dimensional nonlinear systems, without requiring dense state-space sampling. This method is validated through numerical examples, demonstrating its ability to …
Robust Online Inertia Estimation In Power Systems Using Ambient Data In The Presence Of Inverter-Based Resources, Narges Ghiasi
Robust Online Inertia Estimation In Power Systems Using Ambient Data In The Presence Of Inverter-Based Resources, Narges Ghiasi
All Dissertations
The increasing penetration of Inverter-Based Resources (IBRs) in power systems has significantly altered system dynamics, reducing the system's effective rotational inertia and challenging frequency stability. Accurate online inertia estimation is essential for maintaining system reliability under these evolving conditions. This paper introduces a robust methodology for online inertia estimation using ambient data collected during normal system operation. The proposed method employs a state-space model to represent system dynamics and introduces synthetic step changes to simulate disturbances. By analyzing the frequency response and applying advanced signal processing techniques, the methodology estimates system inertia without requiring real large-scale disturbances. The approach is …
An Investigation Into The Impact Of Inverter Based Resources On Critical Clearing Time, Trupal Patel
An Investigation Into The Impact Of Inverter Based Resources On Critical Clearing Time, Trupal Patel
All Dissertations
Renewable energy sources, mainly inverter-based resources (IBRs) such as solar and wind plants are being connected in large numbers to the bulk power grid in the United States and around the world. Additionally, generation using fossil fuels are being phased out, which results in the loss of rotor inertia, a key contributor to the transient stability of power systems. Therefore, the large-signal behavior of IBRs and its impact on transient stability must be studied.
This work studies this impact through the metric of critical clearing time (CCT). Impact of grid topology, generation mix and control modes of IBRs on CCT …
Grid Forming Inverters For Microgrid Operation Enhancement, Jan Westman
Grid Forming Inverters For Microgrid Operation Enhancement, Jan Westman
All Dissertations
Modern electric power systems are confronted with several major challenges including the increasing frequency and severity of weather events, aging infrastructure, high material costs, cyber-attacks, and substantial delays in global supply chains. Microgrids provide a solution to these challenges by insulating customers from the power outages occurring in their local distribution system. A microgrid is a small independent power system with its own power generation and energy storage resources that can supply customers’ electricity needs. When an outage occurs, a circuit breaker will disconnect the microgrid from the distribution system. Successful operation of the microgrid requires one or more devices …
Adaptive Delay Compensation Frameworks For Distributed Real-Time Co-Simulation In Power Systems, Elutunji Buraimoh
Adaptive Delay Compensation Frameworks For Distributed Real-Time Co-Simulation In Power Systems, Elutunji Buraimoh
All Dissertations
This dissertation presents a model-free, adaptive delay prediction and compensation framework for geographically distributed real-time power system co-simulation environments. Communication delays—both constant and real-time-varying—significantly degrade the accuracy, fidelity, and stability of co-simulated systems, particularly in dynamic and transient analyses of partitioned power systems. To address this, a predictor-based framework is developed that compensates for delays without requiring system models, computationally intensive signal transformations, or manual intervention.
The proposed solution leverages a Damping Impedance Method as the interface algorithm, combined with a sliding-mode control-inspired predictor system. Both single-parameter and multi-parameter predictor configurations are implemented, with the multi-parameter design providing an additional …
Real-Time Active Thermal Management And Degradation Forecasting Of Power Electronics Building Blocks In All-Electric Ships, Ali Moghassemi
Real-Time Active Thermal Management And Degradation Forecasting Of Power Electronics Building Blocks In All-Electric Ships, Ali Moghassemi
All Dissertations
With advancements in semiconductor technology, power electronic devices play a critical role in modern power systems, enabling efficient energy conversion in applications such as renewable energy integration, electric vehicle drives, industrial automation, and Navy ship power systems. However, the increasing use of power converters presents challenges such as harmonic reduction, cost optimization, reliability improvement, and thermal management, especially in weight- and space-constrained environments like wind turbines and shipboard systems. High-frequency switching, while reducing passive filter size, increases thermal stress on semiconductor devices, impacting efficiency and longevity. Active thermal control, which regulates junction temperature through power loss management, and degradation forecasting, …
Enhancing Photovoltaic Inverter Reliability Through Advanced Hardware Protection And Simulation Techniques, Buck Brown
Enhancing Photovoltaic Inverter Reliability Through Advanced Hardware Protection And Simulation Techniques, Buck Brown
All Dissertations
Power electronics converter reliability is an issue in today’s grid, and it is an issue that will only become more prevalent as the nation and world move toward greater renewable energy penetration. While a significant amount of research has been conducted pertaining to power electronics converter reliability, (1) there lacks a universal way to protect the most critical component in a power electronics converter—the power device—from the two most common failure modes—short- and open-circuit faults; and (2) there does not exist a tool that considers both the component- and system-levels of a photovoltaic (PV) inverter for the purposes of lifetime …
Hardware Applications Of High-Speed Fault Detection Algorithms, Daniel Zintsmaster
Hardware Applications Of High-Speed Fault Detection Algorithms, Daniel Zintsmaster
All Theses
The growing need for a sustainable electric energy infrastructure has driven research into control, protection, and optimization of power systems. A key challenge is that the changing grid must operate at increasingly higher speeds, but many current hardware devices cannot meet these demands. This thesis focuses on power system protection, aiming to design a hardware solution that can detect and isolate faults in microseconds, ensuring faster, more reliable grid operations. The first hardware developed was for a low-voltage direct current (LVdc) microgrid, which faces challenges due to a lack of protection schemes and novel speed requirements. This thesis presents protection …
Short-Circuit Modeling And Instantaneous Overvoltage Protection Of Renewable Farms, Shah Mohazzem Hossain
Short-Circuit Modeling And Instantaneous Overvoltage Protection Of Renewable Farms, Shah Mohazzem Hossain
All Dissertations
The existing utility grid is experiencing a paradigm shift in electricity generation due to a significant penetration of renewable energy sources. This shift is primarily driven by the large-scale integration of solar and wind energy farms, particularly in the transmission network, where these farms are typically accompanied by battery energy storage in a hybrid configuration to overcome source intermittency and improve reliability. Such renewable farms comprise numerous inverters, pad-mounted transformers, collector feeders, and dc-side components depending on the generation-source type. Additionally, inverters within these farms exhibit distinct operating modes, such as `grid-following'(GFL) and `grid-forming'(GFM), as well as fault control modes, …
Fault Detection And Location In Renewable-Fed Distribution Systems Using Low Voltage Sensors, Bushra Farhat
Fault Detection And Location In Renewable-Fed Distribution Systems Using Low Voltage Sensors, Bushra Farhat
All Theses
The penetration of Distributed Energy Resources (DERs) into the Electric Power System (EPS) is increasing. These (DERs) are mostly inverter-based resources (IBRs) that are integrated into (EPS) at the distribution level. Therefore, it has become necessary to leverage the integration of (IBRs) for both commercial and residential distribution systems through the deployment of Microgrid (MG). However, existing distribution systems that use fuses for sensing and isolating faults are not equipped to handle protection of microgrids where fault currents are fed from multiple sources and can flow downstream or upstream. Bulk of the protection schemes proposed in literature are heavily dependent …
Data-Driven Enhanced Energy Management System Applications For Energy Control Centers, Dulip Madurasinghe
Data-Driven Enhanced Energy Management System Applications For Energy Control Centers, Dulip Madurasinghe
All Dissertations
This dissertation explores the pressing needs of modern bulk power system operation and control and delves into enhancements to EMS applications with minimal infrastructure development. The dissertation investigates three main EMS application enhancements. The transmission network topology processing (TNTP) is a foundational application of the EMS. A physics-based hierarchical transmission network topology processing (H-TNTP), including substation configuration identification, to improve efficiency and reliability is proposed. Secondly, a multi-level distributed linear state estimation (D-LSE) approach solely based on PMUs is proposed utilizing H-TNTP as the network modeling tool. The D-LSE can conduct linear state estimation (LSE) at either substation, area or …
Time-Domain Line Protection In Presence Of Renewables, Prabin Adhikari
Time-Domain Line Protection In Presence Of Renewables, Prabin Adhikari
All Dissertations
Inverter based resources (IBRs) are crucial in integrating renewable energy sources into the power grid. However, their unique fault characteristics, significantly different from synchronous generators (SGs), present several challenges for existing line protection schemes at both transmission and distribution levels. These schemes, reliant on distance and directional relays designed in phasor domain, are not well-suited for IBRs. Most published literature addressing this problem concentrates on altering the control design of inverters. However, this approach faces practical limitations. Inverter controls, often proprietary, are not readily accessible to utilities, rendering the control-based solutions impractical for widespread implementation.
To address this challenge, this …
Phasor-Domain Short-Circuit Analysis Of Power Transmission Systems In The Presence Of Inverter-Based Resources, Dol Kunwar
All Theses
Although a power system is nonlinear during healthy operation because of constant power loads and controlled power injections from the sources, a conventional power system fed by synchronous generators is linear during fault, and can be represented by bus impedance matrix (Z-bus), which is useful in power system analyses such as short circuit (SC) analysis. However, With increasing penetration of inverter-based resources (IBRs) in the system, the assumption of linearity of the faulted network does not hold. This impacts the analyses relying on Z-bus and Thevenin’s equivalent impedance (TEI), such as certain protection schemes set using short circuit analysis. Therefore, …
Photovoltaics And Battery-Based End-To-End Direct Current Sustainable Power Networks- Concept, Design, And Control, Vishwas Powar
Photovoltaics And Battery-Based End-To-End Direct Current Sustainable Power Networks- Concept, Design, And Control, Vishwas Powar
All Dissertations
The consequences of climate change have emphasized the need for a power network that is centered around green, low-cost, and renewable sources of energy. Currently, photovoltaics (PV) and wind turbines are the only two technologies that can convert renewable energy from the sun and wind, respectively, into large-scale power for the electricity network. This dissertation aims to provide a novel solution to implement direct current-based architecture for PV generation coupled with lithium-ion battery storage in an efficient and sustainable manner. Such a power network can enable efficiency, reliability, low cost, and sustainability with minimum impact on the environment. The first …
Real-Time Degradation Abatement Framework For Energy Storage System In Automotive Application Using Data-Driven Approaches, Laxman Timilsina
Real-Time Degradation Abatement Framework For Energy Storage System In Automotive Application Using Data-Driven Approaches, Laxman Timilsina
All Dissertations
The increasing popularity of electric vehicles (EVs) is driven by their compatibility with sustainable energy goals. However, the decline in the performance of energy storage systems, such as batteries, due to their degradation puts EVs and hybrid electric vehicles (HEVs) at a disadvantage compared to traditional internal combustion engine (ICE) vehicles. The batteries used in these vehicles have limited life. The degradation of the battery is accelerated by the operating conditions of the vehicle, which further reduces its life and increases the reliability and economic concerns for the vehicle’s operation. The aging mechanism inside a battery cannot be eliminated but …
Resilient, Sustainable, And Secure Systems Support For Ultra-Low-Power Computational Things, Nicole Tobias
Resilient, Sustainable, And Secure Systems Support For Ultra-Low-Power Computational Things, Nicole Tobias
All Dissertations
Wireless battery-free and energy-harvesting devices are expanding the reach and vision of the Internet of Things, where trillions of embedded computational things interconnect ubiquitously around us and inform many different aspects of our everyday lives. Designing these systems without batteries and interconnecting wires lowers maintenance, environmental, and economic costs while also extending device lifetime and deployment opportunities. Over the last decade, research on these ultra-low-power embedded sensors and systems has dramatically increased — enabling new and exciting prospects in many different scientific fields, from smart building and health monitoring applications to animal and activity tracking.
These systems are not without …
Model-Free Methods To Analyze Pmu Data In Real-Time For Situational Awareness And Stability Monitoring, Sean Kantra
Model-Free Methods To Analyze Pmu Data In Real-Time For Situational Awareness And Stability Monitoring, Sean Kantra
All Dissertations
This dissertation presents and evaluates model-free methodologies to process Phasor Measurement Unit (PMU) data. Model-based PMU applications require knowledge of the system topology, most frequently the system admittance matrix. For large systems, the admittance matrix, or other system parameters, can be time-consuming to integrate into supporting PMU applications. These data sources are often sensitive and can require permissions to access, delaying the implementation of model-based approaches. This dissertation focuses on evaluating individual model-free applications to efficiently perform functions of interest to system operators for real-time situational awareness. Real-time situational awareness is evaluated with respect to central digitization where the PMU …
Hpc-Enabled Fast And Configurable Dynamic Simulation, Analysis, And Learning For Complex Power System Adaptation And Control, Cong Wang
All Dissertations
This dissertation presents an HPC-enabled fast and configurable dynamic simulation, analysis, and learning framework for complex power system adaptation and control. Dynamic simulation for a large transmission system comprising thousands of buses and branches implies the latency of complicated numerical computations. However, faster-than-real-time execution is often required to provide timely support for power system planning and operation. The traditional approaches for speeding up the simulation demand extensive computing facilities such as CPU-based multi-core supercomputers, resulting in heavily resource-dependent solutions. In this work, by coupling the Message Passing Interface (MPI) protocol with an advanced heterogeneous programming environment, further acceleration can be …
A Scalable Transmission And Distribution Co-Simulation Platform For Ibr-Heavy Power Systems, Yousu Chen
A Scalable Transmission And Distribution Co-Simulation Platform For Ibr-Heavy Power Systems, Yousu Chen
All Dissertations
The grid is evolving rapidly to meet the requirements of the clean energy transition. This evolution involves an increasing penetration of renewable energy resources and new complexities with a larger number of devices and controls spread across transmission and distribution networks. The boundary between transmission and distribution becomes blur. Consequently, we face significant challenges in managing the fundamental shift in power system physics. The ubiquitous use of Inverter Based Resources (IBRs) throughout the transmission and distribution systems has made it more difficult for the grid to maintain grid stability under dynamic conditions. Therefore, there is a strong need to explore …
Digital Twins And Artificial Intelligence For Applications In Electric Power Distribution Systems, Deborah George
Digital Twins And Artificial Intelligence For Applications In Electric Power Distribution Systems, Deborah George
All Theses
As modern electric power distribution systems (MEPDS) continue to grow in complexity, largely due to the ever-increasing penetration of Distributed Energy Resources (DERs), particularly solar photovoltaics (PVs) at the distribution level, there is a need to facilitate advanced operational and management tasks in the system driven by this complexity, especially in systems with high renewable penetration dependent on complex weather phenomena.
Digital twins (DTs), or virtual replicas of the system and its assets, enhanced with AI paradigms can add enormous value to tasks performed by regulators, distribution system operators and energy market analysts, thereby providing cognition to the system. DTs …
Universal Short-Circuit And Open-Circuit Fault Detection For An Inverter, Buck Brown
Universal Short-Circuit And Open-Circuit Fault Detection For An Inverter, Buck Brown
All Theses
Short-circuit and open-circuit faults of an inverter’s power device often lead to catastrophic failure of the entire system if not detected and acted upon within a few microseconds, particularly for emerging wide bandgap (WGB) power semiconductors. While a significant amount of research has been done on the fast and accurate protection and detection of short-circuit faults, there has been less success corresponding to the research on open-circuit faults. Common downfalls include protection and detection that are too application-specific, take longer than a couple of microseconds, and are not cost-efficient. This study proposes a new open-circuit fault protection and detection system …
Considerations Of The Impacts And System-Level Mitigation Of Electric Vehicle Charging On The Integrated Resource Planning Process, Grant Wollam
All Theses
Electric vehicles (EV) are growing in popularity and therefore adoption rate. Best estimates predict a 6.2% EV adoption rate by 2035 in the southeastern United States. With this level of EV adoption, utility planners must begin to consider the impact that EVs will have on the power grid. This paper aims to help predict these EV impacts on the power grid. Specifically, an urban-commercial feeder is analyzed in detail to provide worst-case and most-likely results of varying levels of EV impact. Results show that a 26.2% peak increase is the most likely result for this feeder in 2035.
Mitigation techniques …
Photovoltaics, Batteries, And Silicon Carbide Power Electronics Based Infrastructure For Sustainable Power Networks, Prahaladh Paniyil
Photovoltaics, Batteries, And Silicon Carbide Power Electronics Based Infrastructure For Sustainable Power Networks, Prahaladh Paniyil
All Dissertations
The consequences of climate change have emphasized the need for a power network that is centered around clean, green, and renewable sources of energy. Currently, Photovoltaics (PV) and wind turbines are the only two modes of technology that can convert renewable energy of the sun and wind respectively into large-scale power for the electricity network. This dissertation aims at providing a novel solution to implement these sources of power (majorly PV) coupled with Lithium-ion battery storage in an efficient and sustainable approach. Such a power network can enable efficiency, reliability, low-cost, and sustainability with minimum impact to the environment.
The …
Classification Of Electrical Current Used In Electroplastic Forming, Tyler Grimm
Classification Of Electrical Current Used In Electroplastic Forming, Tyler Grimm
All Dissertations
Electrically assisted manufacturing (EAM) is the direct application of an electric current to a workpiece during manufacturing. This advanced manufacturing process has been shown to produce anomalous effects which extend beyond the current state of modeling of thermal influences. These purported non-thermal effects have collectively been termed electroplastic effects (EPEs).
While there is a distinct difference in results between steady-state (ideal DC) testing and pulsed current testing, the very definition of these two EAM methods has not been well established. A "long" pulse may be considered DC current; a "short" pulse may produce electroplastic effects; and even "steady-state" current shapes …