A hybrid algorithm for voltage stability enhancement of distribution systems

This paper presents a hybrid algorithm by applying a hybrid firefly and particle swarm optimization algorithm (HFPSO) to determine the optimal sizing of distributed generation (DG) and distribution static compensator (D-STATCOM) device. A multi-objective function is employed to enhance the voltage stability, voltage profile, and minimize the total power loss of the radial distribution system (RDS). Firstly, the voltage stability index (VSI) is applied to locate the optimal location of DG and D-STATCOM respectively. Secondly, to overcome the sup-optimal operation of existing algorithms, the HFPSO algorithm is utilized to determine the optimal size of both DG and D-STATCOM. Verification of the proposed algorithm has achieved on the standard IEEE 33-bus and Iraqi 65-bus radial distribution systems through simulation using MATLAB. Comprehensive simulation results of four different cases show that the proposed HFPSO demonstrates significant improvements over other existing algorithms in supporting voltage stability and loss reduction in distribution networks. Furthermore, comparisons have achieved to demonstrate the superiority of HFPSO algorithms over other techniques due to its ability to determine the global optimum solution by easy way and speed converge feature.

Radio Over Fiber System for A Four-Store Hospital Building

The goal of this project is to design and analyse a radio over fibre system for a four-story hospital with 20 rooms on each floor. The number of ONUs per floor is 20, and it was assumed that each room had an ONU capable of providing network access to voice, data, video, and biometrics. We build an 80-channel WDM optical transmitter using the WDM method. The proposed system includes a transmitter with 20 input channels, a multiplexer, a DE multiplexer, a 45-kilometer optical fibre, and an amplifier. The proposed model was simulated, and the results were evaluated in WDM systems using an optical amplifier. The receiver performance analysis of the Optical Communication System is shown by the BER simulation run and the eye diagram graphic, with the threshold set at 0.00120739. Furthermore, the eye height is 0.00141402, and the minimum BER is 5.59009e-006. When the simulated and calculated values of received power and total power loss are compared, the system is efficient. Keywords: Radio over fibre, Optical Amplifier, WDM system, DE multiplexer, Multiplexer, BER, Optical transmitter

Concurrent vibration attenuation and low-power electricity generation in a locally resonant metastructure

We investigate piezoelectric energy harvesting on a locally resonant metamaterial beam for concurrent power generation and bandgap formation. The mechanical resonators (small beam attachments on the main beam structure) have piezoelectric elements which are connected to electrical loads to quantify their electrical output in the locally resonant bandgap neighborhood. Electromechanical model simulations are followed by detailed experiments on a beam setup with nine resonators. The main beam is excited by an electrodynamic shaker from its base over the frequency range of0–150 Hz and the motion at the tip is measured using a laser Doppler vibrometer to extract its transmissibility frequency response. The formation of a locally resonant bandgap is confirmed and a resistor sweep is performed for the energy harvesters to capture the optimal power conditions. Individual power outputs of the harvester resonators are compared in terms of their percentage contribution to the total power output. Numerical and experimental analysis shows that, inside the locally resonant bandgap, most of the vibrational energy (and hence harvested energy) is localized near the excited base of the beam, and the majority of the total harvested power is extracted by the first few resonators.

Enhanced Reverse Recovery Performance in Superjunction MOSFET with Reduced Hole-Barrier

High reverse recovery charge (QRR) and resultant high switching losses have become the main factors that constrain the performance and application area of superjunction MOSFET (SJ-MOSFET). To reduce QRR, an SJ-MOSFET with reduced hole-barrier is proposed and demonstrated. By introducing a Schottky contact on the bottom of the n-pillar at the drain side, the barrier for the hole carrier is dramatically reduced in the reverse conduction state. As a result, the hole carrier in the drift region is significantly reduced, which results in a low QRR and enhanced reverse recovery performance. Compared with the conventional SJ-MOSFET (Conv-SJ-MOSFET), the proposed device achieves 64.6% lower QRR with almost no sacrifice in other characteristics. The attenuated QRR accounts for a 19.6% ~ 46.8% reduction in total power losses with operation frequency at 5 ~ 200 kHz, demonstrating the great potential of the proposed SJ-MOSFET used in power conversion systems.

Optimal Siting of Distributed Generation Unit in Power Distribution System considering Voltage Profile and Power Losses

Many underdeveloped countries are facing acute shortage of electric power and short term measures are important to consider to address the problems of power outage, power plant failures, and disaster areas. Distributed generation (DG) is a promising approach for such cases as it allows quick on-site installation and generation of electric power. Injection of DG can improve the system voltage profile and also reduce the system's total power losses. However, the placement and sizing of the DG unit is an optimization problem in the radial distribution system. As a test case, this study examines voltage profile improvement and system power losses for an 11 KV residential feeder at the Abdul Rehman Baba grid station in Pakistan, which is modelled using the Electrical Transient Analyzer Program (ETAP). For various scenarios, several tests are conducted to assess the effects of DG on the distribution system. The results show that proper design considerations of size and location of a DG, to be inserted in to the system, lead to significant reduction in power losses and improvement in voltage profile and thus improvement in the overall efficiency of the power system. The projections of this work can be used to optimize the expansion of a power system and tackling different issues related to voltage profile in distribution sector worldwide.

Power Consumption Model of Permanent-Magnet Direct-Drive Belt Conveyor System Based on GACO–BP

Permanent-magnet direct-drive belt conveyors (PMDDBCs) rotate at high speed most of the time, resulting in a large number of invalid energy consumption. To realize the speed regulation of PMDDBC, it is necessary to clarify the relationship between the belt speed, coal quantity of the conveyor and total power of the system. Based on the BP neural network, this paper establishes the power consumption model of PMDDBC, which is related to coal quantity, belt speed and total power. Furthermore, an improved hybrid algorithm (GACO) that combines the advantages of genetic algorithm (GA) and ant colony optimization (ACO) is proposed to optimize the BP power consumption model. The GACO–BP power consumption model is obtained. The original power consumption model is compared with the GACO–BP power consumption model through experiments. Results demonstrate that the GACO–BP power consumption model reduces various prediction errors, while the optimization ability, prediction accuracy and convergence speed are significantly enhanced. It provides a reliable speed regulation basis for the permanent-magnet direct-drive belt conveyor system and also provides a theoretical reference for energy savings and consumption reduction in the coal industry.

Non-linear MHD modelling of Edge Localized Modes suppression by Resonant Magnetic Perturbations in ITER

Edge Localized Modes (ELMs) suppression by Resonant Magnetic Perturbations (RMPs) was studied with the non-linear MHD code JOREK for the ITER H-mode scenarios at 15MA,12.5MA,10MA/5.3T. The main aim of this work was to demonstrate that ELMs can be suppressed by RMPs while the divertor 3D footprints of heat and particle fluxes remain within divertor material limits. The unstable peeling-ballooning modes responsible for ELMs without RMPs were modelled first for each scenario using numerically accessible parameters for ITER. Then the stabilization of ELMs by RMPs was modelled with the same parameters. RMP spectra, optimized by the linear MHD MARS-F code, with main toroidal harmonics N=2, N=3, N=4 have been used as boundary conditions of the computational domain of JOREK, including realistic RMP coils, main plasma, Scrape Off Layer (SOL) divertor and realistic first wall. The model includes all relevant plasma flows: toroidal rotation, two fluid diamagnetic effects and neoclassical poloidal friction. With RMPs, the main toroidal harmonic and the non-linearly coupled harmonics remain dominant at the plasma edge, producing saturated modes and a continuous MHD turbulent transport thereby avoiding ELM crashes in all scenarios considered here. The threshold for ELM suppression was found at a maximum RMP coils current of 45kAt-60kAt compared to the coils maximum capability of 90kAt. In the high beta poloidal steady-state 10MA/5.3T scenario, a rotating QH-mode without ELMs was observed even without RMPs. In this scenario with RMPs N=3, N=4 at 20kAt maximum current in RMP coils, similar QH-mode behavior was observed however with dominant edge harmonic corresponding to the main toroidal number of RMPs. The 3D footprints with RMPs show the characteristic splitting with the main RMP toroidal symmetry. The maximum radial extension of the footprints typically was ~20 cm in inner divertor and ~40 cm in outer divertor with stationary heat fluxes decreasing further out from the initial strike point from ~5MW/m2 to ~1MW/m2 assuming a total power in the divertor and walls is 50MW.

Design and Implementation of Power-Efficient FSM based UART

The remarkable innovations in technology are driven mainly by the high-speed data communication requirements of the modern generation. The Universal Asynchronous Receiver Transmitter (UART) is one of the most sought-after communication protocols. This work mainly focuses on implementing and analysing the UART for data communication. The Finite State Machine (FSM) implements the baud rate generator, transmitter, and receiver modules. Cadence NCSIM was utilized for simulation, and Cadence RTL Compiler was used during synthesis using the 45 nm and 90 nm General Process Design Kit (GPDK) library files. The baud rate of 9600 bps and 50 MHz clock frequency was used to design UART. The increased speed and complexity of the VLSI chip designs has resulted in a significant increase in power consumption. The comparative analysis of power and delay for different clock periods shows an improvement in the total power and the Power Delay Product (PDP) with increasing clock periods. Better results were observed using 45 nm in comparison to the 90 nm library.

Response Surface Methodology for 30 kW PEMFC stack characterization

Hydrogen is a promising energy carrier to allow the reach of the zero-emission targets established for the next years. Polymeric Electrolyte Membrane FC are studied inside the HI-SEA laboratory of the University of Genoa, to assess the opportunities of this technology on marine applications. Here, 8 PEMFC stacks, sized 30 kW each for a total power installation of 240 kW, have been tested to draw guidelines for the best system design onboard ships and to deepen the know-how on the experimental management of the technology. During the tests, it was possible to observe the reciprocal influence of some parameters, which may influence the system efficiency. In this work, a statistical investigation is developed to quantify the cell voltage variation correlated to the values of temperature and current. This has been possible thanks to Design Expert (DE), a software developed by Stat-EASE, Inc. Through the Design of Experiment approach, it is possible to evaluate the significance of variables in the FC system, called factors. The experiment under consideration is also characterized by non-controllable factors, cause of disturbances that induce further variability in the response. Eventually, it was possible to analyse the significance of the parameters involved, to build a regression model by performing the analysis of variance with which the significant values are identified, and to assess the presence of outliers.

Robotic Expert System for Energy Management in Distributed Grid Ecosystem

A robotic expert system (RES) for energy management (EM) in community-based micro-grids is developed using a fuzzy computational scheme. Within the micro-grid multi-dimensional space, embedded algorithms for residential homes, sectors and central controller units are introduced to perform EM in a collaborative manner. Demand response and load shedding are carried out within the community micro-grid to ascertain the behavioral responses based on changes in power demand levels. Various tests are carried out with an observable low error margin. It was observed that the system reduced the total power demand on the micro-grid by 20% of the total distributed power. Micro-grid RES, neuro-fuzzy control (NFC), and support vector regression (SVR) evaluations are compared considering the home units at 40kW of the generated capacity. The results gave a 35.79%, 31.58% and 32.63% energy demand, respectively. Consequently, RES provides a grid look-ahead prediction, annotated-self healing, and stability restoration.