371 research outputs found

    Full body harness

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    The full body safety harness is a key part of an active fall arrest system. The harness serves two purposes, first, distributing fall forces safely across a worker's body in the event of a free fall, and second, providing freedom of movement sufficient to allow the worker to effectively perform his or her job. The complete body harness incorporates the characteristics of a sit harness that supports the hips and upper legs as well as a chest harness that supports the chest and shoulders. The complete body structure includes the human torso when correctly used and helps to keep it upright during a fall case

    Nonlinear finite element analysis of reinforced concrete beams strengthened with textile fine grained mortar

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    Nowadays, there was an increasing need of repairing and upgrading the reinforced concrete (RC) structure due to the deterioration of the structure. The fibre reinforced polymer (FRP) was commonly used for structural retrofitting purposes. However, owing to the debonding of the FRP from the concrete substrate and high cost of epoxy, it was gradually replaced with textile fine grained mortar (TFGM) nowadays. The TFGM system has been widely used in the construction field nowadays to repair the structure. Our study focus on the strain performances of the concrete surface, steel reinforcement and the textile itself. There were many proven experimental results showing that the TFGM was more effective than the other strengthening method such as FRP plate method. The experimental work done by previous researcher on investigation of strain performances of the concrete surface, steel reinforcement and the textile itself which consists of eleven (11) RC beams with dimension 150 x 200 x 2500 mm. The RC beams were strengthened with FGM and TFGM with 4 layers. The investigation continued with the finite element (FE) strain performance analysis with using Advanced Tool for Engineering Nonlinear Analysis (ATENA) software. The strain of the concrete surface, steel reinforcement and the textile were measured at a mid-point of RC beam. Then, the results of the finite element analysis software ATENA compared against the experimental results. The strain performances of the concrete and steel reinforcement improved noticeably when the number of layers of textile reinforcement used increased

    The effect of data preprocessing on the performance of artificial neural networks techniques for classification problems

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    The artificial neural network (ANN) has recently been applied in many areas, such as medical, biology, financial, economy, engineering and so on. It is known as an excellent classifier of nonlinear input and output numerical data. Improving training efficiency of ANN based algorithm is an active area of research and numerous papers have been reviewed in the literature. The performance of Multi-layer Perceptron (MLP) trained with back-propagation artificial neural network (BP-ANN) method is highly influenced by the size of the data-sets and the data-preprocessing techniques used. This work analyzes the advantages of using pre-processing datasets using different techniques in order to improve the ANN convergence. Specifically Min-Max, Z-Score and Decimal Scaling Normalization preprocessing techniques were evaluated. The simulation results showed that the computational efficiency of ANN training process is highly enhanced when coupled with different preprocessing techniques

    Unified Power Flow Controller: A Brief Review on Tuning and Allocation for Power System Stability

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    The Power System can become unstable due to disturbances. To enhance system stability the Unified Power Flow Controller (UPFC) is tuned and allocated in the System. In this paper, a brief review of UPFC tuning and allocation studies for power systems stability is presented. The databases consulted for literature are the IEEE Xplore, ScienceDirect, Google Scholar and IOP Publications. The search terms used are Allocation, Tuning, UPFC, Power System and Stability to find the literature used in this review. A total of 26 Journal articles and conference papers were found and reviewed based on tuning and allocation studies. The Researchers applied Fuzzy coordination, Genetic Algorithm (GA), Particles Swarm Optimization (PSO), Grey Wolf Optimization (GWO) and Linear Quadratic Tracker (LQT) to tune the UPFC for enhancing power system stability. For studies on UPFC allocation in power systems, the Researchers applied frequency response of power system transfer function, power flow, Tabu Search (TS), PSO and GA. For allocation based on optimization, the Researchers minimized power losses, voltage index and investment costs considering equality and inequality constraints

    Congestion Management Incorporation of FACTS Devices Using Ant Colony Optimization

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    This paper presents Ant Colony Algorithm (ACA) based approach for the allocation of FACTS (Flexible AC Transmission System) devices for the improvement of Power transfer capacity in an interconnected Power System. The ACA based approach is applied on IEEE 30 BUS System. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is noticed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. Ant Colony Algorithm is then applied to find the amount of magnitudes of the FACTS devices. This approach of ACA based placement of FACTS devices is tremendous beneficial both in terms of performance and economy is clearly observed from the result obtained

    LOSS ALLOCATION OF TRANSMISSION LINE AND MINIMIZATION OF LOSS FOR 5 BUS,14 BUS &30 BUS SYSTEMS

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    The paper focuses on the issue of transmission loss allocation and transmission loss minimization by incorporating UPFC injection model using load flow analysis. To investigate the effect of the UPFC on the steady state condition of the system and load flow, different models can be used. These models are usually based on modification of traditional load flow methods. In this project, a mathematical model for UPFC referred as UPFC injection model is used. Since accurate power tracing is very difficult, allocation of losses for a particular transaction (in power business it is buying and selling system) may not be effectively realized. However loss allocation is an important aspect in determining the cost of transmission. Thus a methodology to find the losses accurately is vital. It is imperative to make sure that all users of the transmission network are charged proportionate to their usage and this aspect is all the more important because of the common infrastructure they use. The Z-bus loss allocation method is used to achieve the required objective. This method will promote more efficient network operations when implemented in deregulated electric industries. The Unified Power Flow Controller (UPFC) injection model is incorporated in Load Flow Model by the method of Newton Raphson Algorithm to study its effects for power flow control and losses minimization in the power system. In this project optimal placement of UPFC is conducted based on active power loss Sensitivity factors. Based on these sensitivity factors the UPFC is optimally placed in the required transmission line to investigate the impact of UPFC in the system. The changes in the system are studied to see the impact of the UPFC. The impact of UPFC are analyzed by using 5-Bus, IEE

    Load Flow Analysis with UPFC under Unsymmetrical Fault Condition

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    This paper addresses the comparative load flow analysis with and without Unified Power Flow Controller (UPFC) for six buses, three phase transmission line under unsymmetrical faults (L-G, L-L and L-L-G) in simulation model. Unified Power Flow Controller (UPFC) is a typical Flexible AC Transmission System (FACTS) device playing a vital role as a stability aid for large transient disturbances in an interconnected power system. The main objective of this paper is to improve transient stability of the six bus system. Here active and reactive power on load bus of the system considered has been determined under different fault conditions. UPFC has been connected to the system and its effects on power flow and voltage profile of test system has been determined with various line data and bus data for six buses, three lines power system and simulation model by using simulation toolbox has been developed. In this work a versatile model is presented for UPFC inherent order to improve the transient stability and damp oscillation. Index Terms – Unified Power Flow Controller (UPFC), Control, simulation, transients, line to ground fault (L-G), double line to ground fault (L-L-G), double line fault (L-L
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