Simulation of a rectifier malfunction on an offshore wind system with HVDC transmission

A new integrated mathematical model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase is presented in this paper. The mathematical model considers an offshore variable-speed wind turbine on a floating platform, equipped with a permanent magnet synchronous generator using full-power three-level converter to inject energy into the electric network, through a high voltage direct current transmission submarine cable. The model for the drive train is a discrete three mass, incorporating the dynamic of the moving surface. A case study is presented to access conclusion about the malfunction

Stress, Pressure and Fatigue on Aircraft Maintenance Personal

This paper focuses on an analysis of the stress, the pressure and the fatigue as part of the Dirty Dozen and Human Factors procedures. An online international survey has been carried out to ascertain the professional levels of the fatigue, the stress and their pressure exposure. This work is a contribution to the aeronautical safety in order to alert authorities about the stress, the pressure and the fatigue that aircraft maintenance personnel suffers. Safety is the main driver in aviation related professions. Maintenance related personnel is constantly subjected to several external circumstances that might originate errors in the performance or evaluation in maintenance related tasks. Authorities have clearly regulated flight crew and air traffic controllers working and resting periods, but maintenance personnel regulations do not reflect the same procedures. The Aeronautical industry 4.0 with the upcoming digital transformation will increase the safety margin and it will reduce the aircraft maintenance ground time

Moving least-squares in finite strain analysis with tetrahedra support

A finite strain finite element (FE)-based approach to element-free Galerkin (EFG) discretization is introduced, based on a number of simplifications and specialized techniques in the context of a Lagrangian kernel. In terms of discretization, a quadratic polynomial basis is used, support is determined from the number of pre-assigned nodes for each quadrature point and quadrature points coincide with the centroids of tetrahedra. Diffuse derivatives are adopted, which allow for the use of convenient non-differentiable weight functions which approximate the Dirac-Delta distribution. Due to the use of a Lagrangian kernel, recent finite strain elasto-plastic constitutive developments based on the Mandel stress are adopted in a direct form. These recent developments are especially convenient from the implementation perspective, as EFG formulations for finite strain plasticity have been limited by the previous requirement of updating the kernel. We also note that, although tetrahedra are only adopted for integration in the undeformed configuration, mesh deformation is of no consequence for the results. Four 3D benchmark tests are successfully solved

Fuzzy, integer and fractional order control: application on a wind turbine benchmark model

This paper presents a comparison between proportional integral control approaches for variable speed wind turbines. Integer and fractional-order controllers are designed using linearized wind turbine model whilst fuzzy controller also takes into account system nonlinearities. These controllers operate in the full load region and the main objective is to extract maximum power from the wind turbine while ensuring the performance and reliability required to be integrated into an electric grid. The main contribution focuses on the use of fractional-order proportional integral (FOPI) controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. A comparison between proposed control approaches for the variable speed wind turbines is presented using a wind turbine benchmark model in the Matlab/Simulink environment. Results show that FOPI has improved system performance when compared with classical PI and fuzzy PI controller outperforms the integer and fractional-order control due to its capability to deal with system non linearities and uncertainties

Dynamics of a gyrostat satellite with the vector of gyrostatic moment tangent to the orbital plane

In this paper, a gyrostat satellite in a circular orbit with its gyrostatic moment tangent to the orbital plane and collinear with the orbital speed is studied regarding its equilibria, bifurcation of equilibria, and asymptotic stability conditions. In the general case, where any gyrostat angular momentum is aligned with any of the orbital coordinate frames, interesting results arose regarding its equilibria bifurcation regarding conditions near to the ones presented in this paper, namely equilibria regions outside their main regions near to the orbital plane tangent. For equilibria and bifurcation of equilibria, a symbolic-numerical method is used to obtain the polynomial equations in function of non-dimensional parameters whose roots are equivalent to the number of equilibria positions. For the asymptotic stability, the results are tested using the Lyapunov stability theory scheme

Simulation of a rectifier malfunction on a offshore wind system with HVDC transmission

A new integrated mathematical model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase is presented in this paper. The mathematical model considers an offshore variable-speed wind turbine on a floating platform, equipped with a permanent magnet synchronous generator using full-power three-level converter to inject energy into the electric network, through a high voltage direct current transmission submarine cable. The model for the drive train is a discrete three mass, incorporating the dynamic of the moving surface. A case study is presented to access conclusion about the malfunction.Fundação Ciência e Tecnologia, through IDMEC/LAETA, Instituto Superior Técnico, Universidade de Lisbo

Home energy forecast performance tool for smart living services suppliers under an energy 4.0 and CPS framework

Industry 4.0 is a paradigm consisting of cyber-physical systems based on the interconnection between all sorts of machines, sensors, and actuators, generally known as things. The combination of energy technology and information and technology communication (ICT) enables measure ment, control, and automation to be performed across the distributed grid with high time resolution. Through digital revolution in the energy sector, the term Energy 4.0 emerges in the future electric sector. The growth outlook for appliance usage is increasing and the appearance of renewable energy sources on the electric grid requires strategies to control demand and peak loads. Potential feedback for energy performance is the use of smart meters in conjunction with smart energy man agement; well-designed applications will successfully inform, engage, empower, and motivate con sumers. This paper presents several hands-on tools for load forecasting, comparing previous works and verifying which show the best energy forecasting performance in a smart monitoring system. Simulations were performed based on forecasting of the hours ahead of the load for several households. Special attention was given to the accuracy of the forecasting model for weekdays and weekends. The development of the proposed methods, based on artificial neural networks (ANN), pro vides more reliable forecasting for a few hours ahead and peak loads.info:eu-repo/semantics/publishedVersio

HVDC Power Transmission Simulation for Offshore Wind System with Three-Level Converter

An integrated mathematical model for the simulation of an offshore wind system performance is presented in this paper. The mathematical model considers an offshore variable-speed turbine in deep water equipped with a permanent magnet synchronous generator using multiple point full-power clamped three-level converter, converting the energy of a variable frequency source in injected energy into the electric network with constant frequency, through a HVDC transmission submarine cable. The mathematical model for the drive train is a concentrate two mass model which incorporates the dynamic for the blades of the wind turbine, tower and generator due to the need to emulate the effects of the wind and the floating motion. Controller strategy considered is a proportional integral one. Also, pulse width modulation using space vector modulation supplemented with sliding mode is used for trigger the transistors of the converter. Finally, a case study is presented to access the system performance

Integration of Evora-InovGrid Smartmeters in a Consumer’s SCADA System

This paper develops an energy management system with smart meters integration for electricity consumers in a smart grid context. The integration of a distributor owned smart meter from the main Portuguese electricity distributor – EDP - is developed. The smart meter is connected to a common PC, that runs the Matlab Software and communicates to the SCADA system (Supervisory Control And Data Acquisition) using the OPC Protocol. The SCADA system supervises an industrial network of Programmable Logic Controllers (PLC). The developed control strategy implements a hierarchical cascade controller where inner loops are performed by local PLCs and the outer loop is managed by a centralized SCADA system, which interacts with the entire local PLC network

Sensitivity Analysis Through Error Function of Crystalline-Si Photovoltaic Cell Model Integrated in a Smart Grid

The paper is based on the device representation of PV cell there are different internal parameters that representing their behavior. The internal parameters have impacts on the PV power generation. In this work, a single diode solar cell five parameter model is used to understand the internal parameters’ sensitivity not the efficiency. Sensitivity is important because of giving idea about parameters response to the total system. The more a parameter is sensitive, the more the system is dependent on those parameters. Here the internal parameters called photocurrent, diode saturation current, series resistance, shunt resistance, diode ideality factor, and cell temperature are investigated through the simulation for getting their sensitivity which aims to identify the parameters having much impact on total system, this identification would help to make a better model for the PV panel which could be more faster in real time system to give estimation of the power generation. Better understanding about the parameters is identically significant for modelling the PV system. At the end of this work a simplified model is built with simplified PV structure