Inspired by the concept of preconditioning, we propose a novel method to increase adaptation speed for gradient-based meta-learning methods without incurring extra parameters. We demonstrate that recasting the optimis...
ISBN:
(纸本)9781713871088
Inspired by the concept of preconditioning, we propose a novel method to increase adaptation speed for gradient-based meta-learning methods without incurring extra parameters. We demonstrate that recasting the optimisation problem to a non-linear least-squares formulation provides a principled way to actively enforce a well- conditioned parameter space for meta-learning models based on the concepts of the condition number and local curvature. Our comprehensive evaluations show that the proposed method significantly outperforms its unconstrained counterpart especially during initial adaptation steps, while achieving comparable or better overall results on several few-shot classification tasks - creating the possibility of dynamically choosing the number of adaptation steps at inference time.
AC microgrids may be a target of cyber-attacks such as False Data Injection attack (FDIA) or Denial of Service attacks due to the use of communication technologies. These types of attacks target the communication infr...
AC microgrids may be a target of cyber-attacks such as False Data Injection attack (FDIA) or Denial of Service attacks due to the use of communication technologies. These types of attacks target the communication infrastructure or the control system itself. For instance, FDIAs aim to inject false data into AC microgrids to disrupt the control system. Techniques that detect and mitigate the effect of such attacks are needed. This paper presents an AC microgrid that is structured by parallel inverters and controlled by distributed consensus control strategies to control the frequency and voltage magnitude through active and reactive power. We will investigate the FDIAs effect on the AC microgrid operation. A viable solution to address the FDIA attacks in AC microgrids is developed using an ANN-based reference tracking application to detect and mitigate the attack. The simulation results proved that the proposed strategy could detect and mitigate FDIA attacks especially if the ANN is well trained.
Emerging advanced and innovative Information and Communication Technologies (ICT), automation strategies, and associated algorithms in the traditional power system have transformed it into a Cyber-Physical Power Syste...
Emerging advanced and innovative Information and Communication Technologies (ICT), automation strategies, and associated algorithms in the traditional power system have transformed it into a Cyber-Physical Power System (CPPS). Energy management and control are crucial in the Shipboard Power System operation. For instance, to meet the ship's energy and other ancillary demands, especially the mission-critical loads that require practical and secure network communication. Therefore, a comprehensive modeling and testing and validation approach was developed in this paper. This enables flexible system-level aspect evaluation through numerous experiments, including virtual, real, and mixed lab settings. This paper presents a scalable and flexible three-layer cyber-physical co-simulation platform implemented in the FIU smart grid testbed. This includes real-time power system simulation using OPAL-RT, ns3 for communication network emulation, and MATLAB/SIMULINK for implementing various applications. To demonstrate the platform's effective operation, energy management with a central controller for SPS was configured and implemented to test the communication network performance by creating tools to characterize the network latency for this application.
In the transition to clean, cheap, and sustainable energy, microgrid-based renewable energy resources (RES) are widely utilized in islanded or grid-connected modes. However, due to the intermittent nature of RES such ...
In the transition to clean, cheap, and sustainable energy, microgrid-based renewable energy resources (RES) are widely utilized in islanded or grid-connected modes. However, due to the intermittent nature of RES such as photovoltaic (PV) or wind energy systems, energy storage systems (ESSs) such as batteries are mandated to satisfy load demands and stabilize system operation. For instance, stabilizing the dc bus voltage in islanded microgrids is crucial to keeping the system reliable, dependable, and stable. This paper proposes an adaptive dc bus voltage control technique based on a fuzzy-PI controller. Moreover, a performance comparison between fuzzy-PI and conventional proportional-integrator (PI) controllers is performed based on a MATLAB/Simulink model. The results show that the fuzzy-PI controller has a faster response to any reference voltage variation and less overshoot compared to conventional PI controllers. Additionally, the proposed controller can efficiently stabilize the dc bus voltage during load variation portions.
Power system dynamics have significantly changed with the global integration of renewable energy sources (RESs). Traditionally, the stored kinetic energy is used for compensating the generation mismatch using the rota...
Power system dynamics have significantly changed with the global integration of renewable energy sources (RESs). Traditionally, the stored kinetic energy is used for compensating the generation mismatch using the rotating mass of the Synchronous Generators (SGs). With the increase in RESs penetration, SGs are being replaced by inverter-based RESs generation systems which are decoupled from the power systems through power converters. Therefore, the total inertia of the system has decreased, and the system's stability is significantly impacted as the value of the rate of change of frequency (ROCOF) and frequency deviations will be increased. To overcome these challenges, inertia emulation from various energy storage systems (ESS) is used to act as a virtual source of inertia power. This work presents an isolated microgrid (MG) that includes conventional power generation sources and RESs, and an optimal virtual inertia (VI) control loop is proposed for frequency stability enhancement. Supercapacitors (SC) bank with a PID controller presents the VI control loop and acts as a supplementary source for inertia power to support the frequency stability of the system. A genetic algorithm (GA) is used as an optimization technique to get the optimal values of the PID controller gains. The performance of the islanded MG with the proposed optimal control scheme is examined under different operating conditions with varying levels of RESs penetration and system parameters uncertainties. The proposed technique showed its effectiveness and robustness over the system's operation without VI control for keeping the system stable under different operating conditions.
A power and Energy Management System (P/EMS) is crucial to Microgrid's effective practical and reliable operation. In the Shipboard Microgrid (SMG), the load demand is dominated by the high penetration of propulsi...
A power and Energy Management System (P/EMS) is crucial to Microgrid's effective practical and reliable operation. In the Shipboard Microgrid (SMG), the load demand is dominated by the high penetration of propulsion loads, which is very dynamic. Some particular loads in naval ships draw very high power for very short periods. A hybrid application of battery and supercapacitor is proposed to cater to the energy consumed by pulse load in a naval ship and for backup purposes. The system proposed in this model is a stand-alone SMG with a Photovoltaic (PV) and Hybrid Energy Storage System (HESS). A rule-based energy supervision and power allocation technique have also been presented considering the specific fuel consumption of diesel engine generators and the characteristics of hybrid energy stored sources (battery and supercapacitor) of the entire SMG. The simulation studies using MATLAB/Simulink software indicate that the proposed P/EMS strategy enables management of power and energy contributions of hybrid resources on the ship. In addition, a reasonable allocation of power among HESS units, which can effectively smooth out the load power fluctuations of the proposed SMG has been introduced.
Object detection plays a crucial role in smart video analysis, with applications ranging from autonomous driving and security to smart cities. However, achieving real-time object detection on edge devices presents sig...
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A Power systems are undergoing a rapid change in generation mix due to the growth of Inverter-Based Resources (IBRs) such as wind and solar PV. This rapid growth creates new challenges for protection engineers. The ou...
A Power systems are undergoing a rapid change in generation mix due to the growth of Inverter-Based Resources (IBRs) such as wind and solar PV. This rapid growth creates new challenges for protection engineers. The output current of an IBR facility under short circuit conditions differs significantly from that of a conventional rotating synchronous source facility, posing protection problems. The protection schemes for the transmission line, which were designed locally at the planning stage, may operate reliably for low penetration of IBRs but in the case of high penetration, fault detection and location in the transmission line will be challenged. In this paper, a traveling wave-based protection schemes with the aid of Artificial Neural Network (ANN) as an innovative method to overcome these challenges and facilitate the widespread deployment of IBRs in transmission systems will be presented. A three-bus transmission network with voltage level of 380Kv and 94% of renewables penetration is simulated using DIgSILENT Power Factory is used in this study. The results demonstrates that fault identification is a quick and reliable way to identify a variety of faults, particularly single line to ground faults, which are the most challenging fault for the protection system.
This paper presents an optimal modulation and systematic filter design approach for a single-stage dual-active-bridge (DAB) based dc-ac microinverter to achieve improved differential-mode (DM) noise performance for el...
This paper presents an optimal modulation and systematic filter design approach for a single-stage dual-active-bridge (DAB) based dc-ac microinverter to achieve improved differential-mode (DM) noise performance for electromagnetic interference (EMI) tests. As DM filters contribute significantly to the overall converter volume, the main objective of this work is to leverage the degrees of freedom in the DAB converters to effectively attenuate the EMI noise. In addition, the DM filter design method needs to ensure near unity power factor converter operation. To achieve these targets, this paper analyzes three modulation strategies based on fixed or variable switching frequency operation where the different control modulation variables are varied to find the simulated DM noise spectrum. Based on the required DM attenuation, a constrained optimization problem is formulated to determine minimal DM filter parameters. Simulation results show that a spread spectrum approach with variable switching frequency is shown to minimize the DM EMI attenuation effort by spreading the noise profile. A fully GaN 400 W hardware prototype demonstrating the spread-sprectrum approach.
Contemporary neural network (NN) detectors for power systems face two primary challenges. First, each power system requires individual training of NN detectors to accommodate its unique configuration and base demands....
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ISBN:
(数字)9798331541033
ISBN:
(纸本)9798331541040
Contemporary neural network (NN) detectors for power systems face two primary challenges. First, each power system requires individual training of NN detectors to accommodate its unique configuration and base demands. Second, significant changes within the power system, such as the introduction of new substations or new generators, necessitate retraining. To overcome these issues, we introduce a novel architecture, the Nodal Graph Convolutional Neural Network (NGCN), which utilizes graph convolutions at each bus and its neighborhoods. This approach allows the training process to encompass multiple power systems and include all buses, thereby enhancing the transferability of the method across different power systems. The NGCN is particularly effective for detection tasks, such as cyber-attacks on smart inverters and false data injection attacks. Our tests demonstrate that the NGCN significantly improves performance over traditional NNs, boosting detection accuracy from approximately 85% to around 97% for the aforementioned task. Furthermore, the transferable NGCN, which is trained by samples from multiple power systems, performs considerably better in evaluations than the NGCN trained on a single power system.
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