To achieve net-zero emission in America by 2050, high voltage transmission capacity must expand ~60% by 2030 and triple by 2050 to connect further wind and solar facilities to demand. This expansion requires a capital...
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ISBN:
(数字)9798350349535
ISBN:
(纸本)9798350349542
To achieve net-zero emission in America by 2050, high voltage transmission capacity must expand ~60% by 2030 and triple by 2050 to connect further wind and solar facilities to demand. This expansion requires a capital investment in transmission capacity of $360 billion by 2030 and $2.4 trillion by 2050. Considering the high cost of building transmission lines, innovations toward high-capacity overhead lines have been targeted to reduce the number of transmission lines required. In our previous studies, we introduced unconventional high-capacity transmission lines. To realize these novel transmission lines, various aspects of line design should be studied, and this paper addresses determining the location and number of shield wires to protect these novel lines against lightning strikes. Lightning-induced overvoltage across line insulators is one of the key factors in power system outages. The design meets the shielding failure flashover rate (SFFOR)
$\leq 0.05/100$
km-years for all three phases of the unconventional high-capacity transmission line. Brown-Whitehead equations were used to measure and analyze the striking distance for vertical strokes.
This study examines how fast rise times, which are common in modern power electronics and drive systems, affect the aging of electric machine windings. It focuses on how to ensure these windings can last longer and wo...
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ISBN:
(数字)9798350366679
ISBN:
(纸本)9798350366686
This study examines how fast rise times, which are common in modern power electronics and drive systems, affect the aging of electric machine windings. It focuses on how to ensure these windings can last longer and work reliably in electricalsystems. A twisted pair magnet wire with insulation commonly used in wound machines was used to get experimental data to understand how different voltage waveforms can influence endurance testing of motor insulation systems powered by inverters. Unlike past studies that looked at comparatively slower rise times and fewer repetitions, this research specifically addresses the challenges posed by next-generation wide bandgap (WBG)-based conversion systems. These systems operate at very high speeds, up to 100 kV/μs, and switch frequencies up to 500 kHz, where both frequency and rise time are crucial factors affecting insulation aging over time.
This paper introduces a high-voltage test system tailored specifically for transmission expansion planning (TEP). The network incorporates long transmission lines, and the line series impedance and shunt admittance fo...
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ISBN:
(数字)9798350349535
ISBN:
(纸本)9798350349542
This paper introduces a high-voltage test system tailored specifically for transmission expansion planning (TEP). The network incorporates long transmission lines, and the line series impedance and shunt admittance for each line are computed utilizing the equivalent
$\pi$
circuit model for long transmission lines to account for the distributed nature of line parameters. The proposed test system offers technically feasible load flow solutions under normal and all single contingency conditions for three distinct loading scenarios: peak, dominant, and light loading conditions. As the real power system is subject to various loading scenarios and should be effectively operable under all conditions, this test system accurately replicates the properties of real power systems. The test system introduced in this paper can be a valuable resource for TEP research.
Since transportation is one of the primary sources of greenhouse gas (GHG) emissions, its electrification is essential for achieving the net-zero GHG emissions target. As a part of transportation electrification, all-...
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ISBN:
(数字)9798350349535
ISBN:
(纸本)9798350349542
Since transportation is one of the primary sources of greenhouse gas (GHG) emissions, its electrification is essential for achieving the net-zero GHG emissions target. As a part of transportation electrification, all-electric aircraft (AEA) have emerged as a viable approach to achieve net-zero emissions in aviation. Electric power systems (EPS) with high power density and low system mass are required for future wide-body AEA. Power cables, as one of the key components of the aircraft EPS, must be constructed to maximize the overall power density of the EPS. Because of the limited heat transfer by convection at cruising altitudes of wide-body AEA, the design of power cables faces significant thermal challenges. These difficulties are worsened using bipolar MVDC EPSs, which are generally composed of two power cables, negative and positive poles, adjacent to one another. Heat transfers that occur through convection and radiation are influenced by the cable's surface area. To offset the decrease in convective heat transfer brought on by the low air pressure, one method is to apply forced heat convection. Increasing the velocity of forced air in a cable duct, either the surface temperature of the cable can be reduced, or the core diameter can be reduced along with the cable weight maintaining the same temperature obtained from natural heat convection. This paper examines the impact of forced heat convection on a conventional cylindrical bipolar cable system. The cable system is equipped with our novel designed ARC-SCT-MMEI insulation system delineated in the paper, and its performance is compared to that of natural heat convection.
Planning, managing, and maintaining solar photovoltaic (PV) plants is becoming increasingly challenging as a result of their increasing implementation world-wide. Solar PV power generation estimations provide a source...
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ISBN:
(数字)9798350360868
ISBN:
(纸本)9798350360875
Planning, managing, and maintaining solar photovoltaic (PV) plants is becoming increasingly challenging as a result of their increasing implementation world-wide. Solar PV power generation estimations provide a source of knowledge and certainty, assisting system operators in day-to-day responsibilities. Digital twins (DTs) replicate physical entities within a virtual setting, providing a real-time platform to perform solar PV power generation estimations, further enhancing situational awareness and operational efficiency. In this paper, a DT is developed and implemented for Clemson University's 1 MW solar PV plant located in South Carolina, USA to perform solar PV power generation estimations. An ensemble of Elman recurrent neural networks (ERNNs) is utilized in the DT for solar PV power generation estimations, replicating PV plant behaviors and characteristics. The ERNN ensemble utilizes data collected at the PV plant site, i.e. generated power, solar irradiance and ambient temperature. The DT's performance is evaluated based on different weather conditions and ERNN ensemble's output selection methods. Typical results are presented to show the effectiveness of the neural network ensemble based DT for solar PV power generation estimations.
Designing power cables that provide high power and low system mass is one of the major goals in achieving the future all-electric wide-body aircraft. Radiative and convective heat transfers from a cable's surface ...
Designing power cables that provide high power and low system mass is one of the major goals in achieving the future all-electric wide-body aircraft. Radiative and convective heat transfers from a cable's surface to the surrounding air determine how much current is permitted to flow through it. At a cruising altitude of 12.2 km (18.8 kPa) for wide-body aircraft, the limited heat transfer by convection poses thermal issues for the design of aircraft cables. These thermal challenges are exacerbated for bipolar electric power systems (EPS), which are usually made up of two power lines next to each other. The cable's surface area affects both convective and radiative heat transfers. Changing the shape of the cable is one technique to improve heat transfers and compensate for the reduced convective heat transfer caused by low air pressure. In comparison to cylindrical and cuboid cables, the rectangular geometry design gives a bigger contact area with the surrounding atmosphere for the same cross-section area, hence it is anticipated that the heat transfer would rise and as a result, the cable's maximum power-carrying capability will be higher. The purpose of this paper is to design ±5 kV bipolar MVDC power cables with rectangular geometry to raise the maximum current carrying capacity of the cable and analyze its performance with bipolar cylindrical and cuboid geometries.
This paper introduces a new 17-bus 500 kV test system that has been specially designed to support transmission expansion planning studies. Unlike other test systems that have been developed for power system analysis, ...
This paper introduces a new 17-bus 500 kV test system that has been specially designed to support transmission expansion planning studies. Unlike other test systems that have been developed for power system analysis, this system is unique because it focuses exclusively on transmission expansion planning at high voltage levels. Existing test systems that are used for TEP studies, in combination with electricity market problems or for integrating new generation or loads, tend to consider the system operations only under normal conditions and one loading condition. However, in practical scenarios, the system must be able to operate under different loading conditions and single contingencies to ensure reliability. Therefore, a reliable test system should mimic the behavior of a real power system, operating under both normal and all single contingency conditions for different loading conditions. This paper addresses this need by introducing a 17-bus 500 kV test system that can operate successfully under three different loading conditions (peak load, dominant load - 60% of peak load, and light load - 40% of peak load), while also being able to handle the operation at normal and single contingency conditions in each case.
Automotive radar has been extensively utilized in cars for many years as an essential sensor, primarily due to its robustness in extreme weather conditions, its capacity to measure Doppler information in the surroundi...
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ISBN:
(数字)9798350348811
ISBN:
(纸本)9798350348828
Automotive radar has been extensively utilized in cars for many years as an essential sensor, primarily due to its robustness in extreme weather conditions, its capacity to measure Doppler information in the surrounding environment, and its cost-effectiveness. Recently, developments in radar technologies and the availability of open-source radar data sets have attracted more attention to radars and using them for perception tasks in deep learning based autonomous driving. However, annotating radar data for large-scale autonomous driving perception tasks is challenging, i.e., it is difficult for humans to label this data and often requires a semi-automatic approach that involves projecting labels from other sensors, such as cameras and LiDARs. The lack of high-quality labeled data has limited the performance of radar perception models. In this paper, we propose MVRAE, a Multi-View Radar AutoEncoder, which employs self-supervised learning to learn meaningful representations from multi-view radar data without any labels. Our approach is based on the intuition that a good representation for multi-view radar data, which includes range-angle, range-Doppler, and angle-Doppler views, should enable the reconstruction of one view solely from the representations of the other two views. Experimental results demonstrate that our proposed self-supervised method, that can be used as a pre-training step for autonomous driving task, allows the model to learn meaningful representations from unlabeled radar data and achieves enhanced label efficiency for downstream tasks, such as radar semantic segmentation. To the best of our knowledge, MVRAE is the first work that employs self-supervised learning and conducts systematic experiments with multi-view radar data.
The need for lunar surface power is expected to grow to megawatt levels, which is in line with NASA's objective of building a long-term human presence on the moon that can house more than 100 people. As humanity s...
The need for lunar surface power is expected to grow to megawatt levels, which is in line with NASA's objective of building a long-term human presence on the moon that can house more than 100 people. As humanity seeks to establish a long-term presence on the moon and construct lunar habitats or bases, the importance of efficient and dependable power transmission on the moon becomes crucial. Power lines of varied lengths and power transfer capacities are needed for a lunar-based power system to link the various power generation, energy storage, and load facilities dispersed over the lunar surface. Developing power lines with high power density, while considering weight, volume, safety, cost-effectiveness, and reliability in the harsh lunar environment, poses a significant challenge. Three potential locations for power lines on the lunar surface can be considered: above the surface, on the surface, or below the surface. The extreme lunar environment, characterized by factors such as temperature variation, micrometeoroid bombardment, and ionizing radiation, limits the effectiveness of the first two methods for power transfer on the moon. Underground deployment offers both safety and convenience. Using the COMSOL Multiphysics software, this work proposes a novel method for designing and assessing affordable bipolar HVDC cables for power transmission below the lunar surface with an emphasis on its electrical insulation difficulties. At a voltage level of up to ±10 kV, the cables are intended to transfer power at two different levels: medium power (500 kW), and high power (1 MW). These specially designed cables offer a viable solution for power transmission on the moon, as they are capable of functioning effectively in harsh lunar conditions.
The integration of (ultra) wide bandgap (UWBG) semiconductor technologies, such as silicon carbide and diamond, is crucial for the advancement of zero-emission vehicles (ZEVs), all-electric aircraft (AEA), and renewab...
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ISBN:
(数字)9798350379617
ISBN:
(纸本)9798350379624
The integration of (ultra) wide bandgap (UWBG) semiconductor technologies, such as silicon carbide and diamond, is crucial for the advancement of zero-emission vehicles (ZEVs), all-electric aircraft (AEA), and renewable energy systems. These technologies operate at higher temperatures, frequencies, and voltages, necessitating the development of novel materials that can endure these demanding conditions. Specifically, the polymeric encapsulation materials currently in use, such as silicone gel and epoxy resin, must be replaced with materials possessing superior properties in every aspect. This paper evaluates the suitability of dibenzyltoluene (DBT), a dielectric liquid, by assessing its thermal conductivity, viscosity, and dielectric breakdown strength under AC voltage. The effects of increased temperature on these properties are examined. Compared to room temperature, DBT exhibits minimal decline in both breakdown strength and thermal conductivity, which are crucial characteristics for insulating media in power modules. When these properties are compared to those of silicone gel, the superior performance of DBT becomes evident. This paper also briefly highlights the challenges to be considered when selecting a dielectric liquid, using the issues related to DBT as a reference.
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