Designing high-power-delivery and low-system-mass electric power systems (EPS) is a major goal to achieve the next generation of electrified aircraft. As one of its major components, cables must be redesigned to obtai...
Designing high-power-delivery and low-system-mass electric power systems (EPS) is a major goal to achieve the next generation of electrified aircraft. As one of its major components, cables must be redesigned to obtain high-power-density and low-system-mass EPS. Among challenges in designing aircraft cables such as arc and arc tracking, partial discharges (PD), and thermal management, the latter is decisive since the thermal properties of the cable determine its maximum ampacity. The maximum permissible current of a cable depends on radiative and convective heat transfers from its surface to the ambient environment. At the cruising altitude (12.2 km) of wide-body aircraft where the air pressure is 18.8 kPa, the convective heat transfer is greatly reduced which results in a reduction in maximum permissible current. Moreover, both radiative and convective heat transfers depend on the surface area of the cable. One way to increase the heat transfers and compensate for the reduction of convective heat transfer from a limited air pressure is to change the geometry of the cable. The cuboid geometry design provides a larger contact area with the ambient environment for the same cross-section area, so it is expected that the heat transfer will increase compared to conventional cylindrical cables, and in turn, the maximum power carrying capacity of the cable will be larger. Here, the question is whether the hypothesis is true, and if so, how much improvement can be expected. The purpose of this paper is to answer these questions and, for the first time, an MVDC (5 kVdc) high power (1 kA) cuboid shape cable is designed for future AEA to increase the maximum permissible current of the cable.
Corona discharges cause power loss, audible noise (AN), radio interference (RI), and television interference (TVI), all of which should be considered during transmission line design. Unconventional high surge impedanc...
Corona discharges cause power loss, audible noise (AN), radio interference (RI), and television interference (TVI), all of which should be considered during transmission line design. Unconventional high surge impedance loading (HSIL) lines have been shown to have the potential to produce greater natural power than conventional lines and conventional HSIL lines. More than one conductor is used in conventional extra high voltage (EHV) lines, typically more than 300 kV, to form bundled conductors which reduce the electrical field on the subconductors and, as a result, reduce corona effects. In conventional lines, the number of subconductors symmetrically placed on a circle and bundle radius are determined based on corona effects considerations. Using a larger bundle circle and increasing the number of subconductors lead to greater natural power, resulting in conventional HSIL lines. Therefore, in conventional HSIL lines, bundled conductors are used not only to address corona effects but also to increase natural power. Using smaller conductors for conventional HSIL lines keeps costs close to conventional lines. In conventional HSIL lines, subconductors are still symmetrically placed on a circle while unconventional HSIL lines have subconductors placed at any point in space. Unconventional HSIL lines can lead to more natural power than conventional HSIL lines. In this paper, AN and RI for unconventional HSIL lines are calculated and discussed.
Transmission expansion planning (TEP) is crucial for maintaining the reliable and efficient operation of the power systems, particularly in the face of increasing electricity demand and the integration of renewable en...
Transmission expansion planning (TEP) is crucial for maintaining the reliable and efficient operation of the power systems, particularly in the face of increasing electricity demand and the integration of renewable energy sources. This paper aims to investigate the application of unconventional high surge impedance loading (HSIL) lines in TEP and presents a comparative analysis of their outcomes against conventional line-based TEP approaches. Starting with a 17-bus 500 kV test system, which can operate well under normal operating condition as well as all single contingency conditions, the objective is to connect a new load located in a new bus, bus #18, to the existing test system via two approaches: using conventional lines and incorporating unconventional HSIL lines. By comparing the number of lines required for the conventional and unconventional approaches, maintaining identical conductor weight per circuit, the effectiveness of unconventional HSIL lines in TEP is evaluated where using only two unconventional HSIL lines is sufficient to connect 1250 MW load demand at bus 18 while three transmission lines are required when using the conventional line. Finally, a thorough economic analysis has been conducted on both TEP scenarios, revealing that implementing unconventional HSIL lines leads to remarkable cost savings and thus can be considered a promising option for TEP studies.
Digital twins have a major potential to form a significant part of urban management in emergency planning, as they allow more efficient designing of the escape routes, better orientation in exceptional situations, and...
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The electric field intensity on subconductors is the most important parameter to consider when electrically designing (extra) high voltage, (E)HV, transmission lines. In this regard, it is not possible to use existing...
The electric field intensity on subconductors is the most important parameter to consider when electrically designing (extra) high voltage, (E)HV, transmission lines. In this regard, it is not possible to use existing formulae for calculating electric field intensity on subconductors, which are for subconductors placed symmetrically on bundle circles, for recently introduced unconventional high power density lines where subconductors can be located in unsymmetrical or at any location in the space. Further, in existing formulas, nearby (other phases) and image conductors are ignored, and a uniform field is assumed despite the fact that electric fields are distorted in the presence of other subconductors in a bundle. None of the mentioned assumptions are valid for unconventional high power density lines, so it is necessary to develop an innovative method for calculating electric field on subconductors on these new lines. In our method, $n_{m}$ line charges for each subconductor are employed to set the electric potentials of $n_{m}$ points at the periphery of that subconductor equal to the applied voltage. The line charges are uniformly distributed around a hypothetical cylinder with a radius of $r/2$ , where $r$ is the radius of that subconductor. The challenge is choosing a proper $n_{m}$ , leading to an accurate result.
Among various sensors for assisted and autonomous driving systems, automotive radar has been considered as a robust and low-cost solution even in adverse weather or lighting conditions. With the recent development of ...
Among various sensors for assisted and autonomous driving systems, automotive radar has been considered as a robust and low-cost solution even in adverse weather or lighting conditions. With the recent development of radar technologies and open-sourced annotated data sets, semantic segmentation with radar signals has become very promising. However, existing methods are either computationally expensive or discard significant amounts of valuable information from raw 3D radar signals by reducing them to 2D planes via averaging. In this work, we introduce ERASE-Net, an Efficient RAdar SEgmentation Network to segment the raw radar signals semantically. The core of our approach is the novel detect-then-segment method for raw radar signals. It first detects the center point of each object, then extracts a compact radar signal representation, and finally performs semantic segmentation. We show that our method can achieve superior performance on radar semantic segmentation task compared to the state-of-the-art (SOTA) technique. Furthermore, our approach requires up to 20×less computational resources. Finally, we show that the proposed ERASE-Net can be compressed by 40% without significant loss in performance, significantly more than the SOTA network, which makes it a more promising candidate for practical automotive applications.
Abnormal climates due to global warming have emerged as a big concern in the global community. To mitigate climate change and achieve sustainability, distributed energy resources (DERs), including solar and wind, have...
Abnormal climates due to global warming have emerged as a big concern in the global community. To mitigate climate change and achieve sustainability, distributed energy resources (DERs), including solar and wind, have been recently deployed in power systems. As the penetration level of DERs has increased, however, it caused a multitude of issues in the power systems, such as voltage fluctuation in the distribution network limiting renewable hosting capacity. On the other hand, the electric vehicle (EV) industry is rapidly growing to facilitate the transition to a carbon-neutral community, illuminating the potential of EVs as a flexible grid asset to mitigate some of the issues and improve grid operation, if properly exploited. To explore the potential of EVs, this paper proposes an EV scheduling strategy. By using an optimal EV charging scheduling proposed, distribution system operators (DSOs) can minimize their operating costs and stably operate the system with a high level of DERs. To validate the method, a modified IEEE 33-bus system with DERs is developed. The case study shows the proposed scheduling strategizes EV charging to reduce the cost of PV curtailment. In the study, the method outperforms the renewable-only case with curtailment by 4.97% in DSO cost. It also demonstrates its potential to increase the renewable hosting capacity by harmonizing EV charging with renewables.
This work proposes a novel and provably correct method for three-dimensional optimal motion planning in complex environments. Our approach models the 3D motion planning problem by solving streamlines of the potential ...
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ISBN:
(数字)9798350377705
ISBN:
(纸本)9798350377712
This work proposes a novel and provably correct method for three-dimensional optimal motion planning in complex environments. Our approach models the 3D motion planning problem by solving streamlines of the potential fluid flow, filling a gap in traditional motion planning techniques by guaranteeing a closed-loop, smooth and natural-looking navigation solution. Special emphasis is given to an inherent challenge of artificial potential field (APF) methods, namely establishing proofs of safety and stability over the entire optimization process. A model-based actor-critic reinforcement learning algorithm is introduced to approximate the optimal solution to the Hamilton-Jacobi-Bellman equation and update the controller parameters in a deterministic manner. Through a series of ROS-Gazebo software-in-the-loop simulations the proposed methodology demonstrates robustness and outperforms widely used methods such as the RRT
∗
, highlighting its contribution to the field of 3D optimal motion planning.
Corona effects are one of the most important factors to take into consideration when designing an overhead transmission line. Corona discharges cause power loss which should be considered during transmission line desi...
Corona effects are one of the most important factors to take into consideration when designing an overhead transmission line. Corona discharges cause power loss which should be considered during transmission line design. Unconventional high surge impedance loading (HSIL) lines have subconductors placed anywhere in space and have no bundle symmetry. They have the potential to produce greater natural power than conventional lines and conventional HSIL lines. This paper calculates corona loss in both fair and foul weather conditions for an envisaged unconventional HSIL line. It is seen that the unconventional lines under discussion undergo much greater corona loss than the conventional lines and conventional HSIL lines.
Cyber-physical distribution systems (CPDS) have emerged from the integration of information technology into distribution systems. While offering substantial benefits, this integration also introduces vulnerabilities. ...
Cyber-physical distribution systems (CPDS) have emerged from the integration of information technology into distribution systems. While offering substantial benefits, this integration also introduces vulnerabilities. The interaction between cyber networks and distribution systems renders CPDS susceptible to disasters. To ensure critical load supply and system resilience, rapid post-disaster load restoration is required. The paper proposes a critical load restoration (CLR) framework in CPDS using a network reconfiguration approach that exploits the existing post-disaster resources to restore critical loads within the shortest possible time. Using graph theory, the cyber network and distribution system are integrated into a single digraph, minimizing the CLR complexity in CPDS. A cost metric is also defined to satisfy network-specific objectives and constraints. A heuristic is proposed to guide the load restoration process using the cost metric within the integrated digraph. Simulation results confirm the framework’s superiority over existing literature, which either overlooks cyber components or prolongs restoration with additional resource deployment.
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