Enhanced leader PSO (ELPSO): A new algorithm for allocating distributed TCSC’s in power systems

Allocation of flexible AC transmission systems (FACTS) devices is a challenging power system problem. This paper proposes a new particle swarm optimisation (PSO) variant, called enhanced leader PSO (ELPSO), for solving this problem. This algorithm is capable of solving FACTS allocation problem in a way leading to lower amounts of power flow violations, voltage deviations and power losses with respect to other optimisation algorithms. Distributed thyristor controlled series compensators (D-TCSC’s) are used. D-TCSC’s are installed at all branches except those with regulating transformers. The reactances of D-TCSC’s are found in optimisation process. ELPSO features a five-staged successive mutation strategy which mitigates premature convergence problem of conventional PSO. ELPSO and other optimisation algorithms are applied to IEEE 14 bus and 118 bus power systems for N-1 contingencies and also for simultaneous outage of four branches. The results show that it leads to lower amounts of power flow violations, voltage deviations and power losses with respect to conventional PSO (CPSO) and eight other optimisation algorithms including genetic algorithm (GA), gravitational search algorithm (GSA), galaxy based search algorithm (GBSA), invasive weed optimisation (IWO), asexual reproduction optimisation (ARO), threshold acceptance (TA), pattern search and nonlinear programming (NLP).     

Optimal placement of UPFC in power systems using immune algorithm

This paper presents the application of immune algorithm (IA) to find optimal location of unified power flow controller (UPFC) to achieve optimal power flow (OPF) and congestion management. Objective function in the OPF, that is to be minimized, is the overall cost functions, which includes the total active and reactive production cost function of the generators and installation cost of UPFCs. The OPF constraints are generators, transmission lines and UPFCs limits. In power system, it may not always be possible to dispatch all of the contracted power transactions due to congestion of the transmission corridors. We propose IA method to minimize the objective function under all equality and inequality constraints. Simulations are performed on 4-bus, IEEE 14-bus and IEEE 30-bus test systems for optimal location of UPFC and the results obtained are encouraging and will be useful in electrical restructuring.     

Numerical study of heat transfer in a wall of vertically perforated bricks: influence of assembly method

Vertically perforated bricks were developed with the view to building environmentally friendly houses since they make insulating materials unnecessary. Indeed, walls can be constructed without any other materials than clay and mortar. Furthermore, they offer better mechanical properties than horizontally perforated ones. However, heat transfer in this geometry, and particularly the influence of the assembly method, is not totally known. In this numerical study, we propose to verify that convection heat transfer is negligible in the perforations. This condition is necessary to increase the thermal resistance of the brick. We then show that a masonry bedded on several strips does not penalize the thermal performance of the wall. A particular study of the ruptures concludes that the convection present in these regions is a local phenomenon preferable to the thermal bridges caused by continuous mortar joints.     

Machines, Tools and Tool Transporter Concurrent Scheduling in Multi-machine FMS with Alternative Routing Using SymbioticOrganisms Search Algorithm

This study explored the concurrent scheduling of machines, tools, and tool transporter(TT) with alternative machines in a multi-machine flexible manufacturing system(FMS), taking into mind the tool transfer durations for minimization of the makespan(MSN). When tools are expensive, just a single copy of every tool kind is made available for use in the FMS system. Because the tools are housed in a central tool magazine(CTM), which then distributes and delivers them to many machines, because there ...     

Single and bivalent metal-cations co-doped ZnO nanopowders: synthesis and characterization

Journal of Materials Science: Materials in Electronics - Ultraviolet light-based devices have received great attention due to their applications in various fields including health, industry, and...