An improved non-adiabatic FEM model of a line-to-earth fault in buried power cables

It is shown in this paper that the non-adiabatic nature of phase-to-earth fault thermodynamics in buried power cables can be modelled in an even more precise manner by using the FEM. The nonlinear FEM model has been created on the basis of an authentic case of fault caused by a previous mechanical damage of the cable sheath and insulation, as well as heat sources, thermo-physical and electrical material properties as functions of temperature and time. The proposed model is applicable to power cables of all voltage levels with different polymer insulations laid in soils with changeable moisture content, as well as to the dry arc tracking or wet arc tracking phenomena in PVC-insulated cables.     

Optimal Power Flow Using a Hybrid Optimization Algorithm of Particle Swarm Optimization and Gravitational Search Algorithm

Abstract—This article presents a hybrid algorithm based on the particle swarm optimization and gravitational search algorithms for solving optimal power flow in power systems. The proposed optimization technique takes advantages of both particle swarm optimization and gravitational search algorithms by combining the ability for social thinking in particle swarm optimization with the local search capability of the gravitational search algorithm. Performance of this approach for the optimal power flow problem is studied and evaluated on standard IEEE 30-bus and IEEE 118-bus test systems with different objectives that reflect fuel cost minimization, voltage profile improvement, voltage stability enhancement, power loss reduction, and fuel cost minimization with consideration of the valve point effect of generation units. Simulation results show that the hybrid particle swarm optimization–gravitational search algorithm provides an effective and robust high-quality solution of the optimal power flow problem.     

GA-based approach for optimal placement and sizing of passive power filters to reduce harmonics in distorted radial distribution systems

Electrical Engineering - This paper presents a Genetic Algorithm-based approach for optimal placement and sizing of passive power filters to mitigate harmonics in radial distribution systems with...     

Optimal power flow for distribution networks using gravitational search algorithm

This paper presents a gravitational search algorithm (GSA)-based approach to solve the optimal power flow (OPF) problem in a distribution network with distributed generation (DG) units. The OPF problem is formulated as a nonlinear optimization problem with equality and inequality constraints, where optimal control settings in case of fuel cost minimization of DG units, power loss minimization in the distribution network, and finally simultaneous minimization of the fuel cost and power loss are obtained. The proposed approach is tested on an 11-node test system and on a modified IEEE 34-node test system. Simulation results obtained from the proposed GSA approach are compared with that obtained using a genetic algorithm approach. The results show the effectiveness and robustness of the proposed GSA approach.     

Energy and operation management of a microgrid using particle swarm optimization

This article presents an efficient algorithm based on particle swarm optimization (PSO) for energy and operation management (EOM) of a microgrid including different distributed generation units and energy storage devices. The proposed approach employs PSO to minimize the total energy and operating cost of the microgrid via optimal adjustment of the control variables of the EOM, while satisfying various operating constraints. Owing to the stochastic nature of energy produced from renewable sources, i.e. wind turbines and photovoltaic systems, as well as load uncertainties and market prices, a probabilistic approach in the EOM is introduced. The proposed method is examined and tested on a typical grid-connected microgrid including fuel cell, gas-fired microturbine, wind turbine, photovoltaic and energy storage devices. The obtained results prove the efficiency of the proposed approach to solve the EOM of the microgrids.     

Laserbasierte Generierung matrixbinderfreier Nanopartikel‐Polymerkomposite für bioaktive Medizinprodukte

New production technologies are required to benefit of the full potential of nanocomposites by homogeneous dispersion of nanoparticles along the process chain. Synthesis of silver nanoparticles by laser ablation in liquid and their integration into polymers are presented. Antibacterial properties of these materials and processability into prototypes for medical devices with antibacterial protection are demonstrated.