Search results for "Volt"
showing 10 items of 2187 documents
Voltage Regulation and Power Losses Minimization in Automated Distribution Networks by an Evolutionary Multiobjective Approach
2004
In this paper, the problem of voltage regulation and power losses minimization for automated distribution systems is dealt with. The classical formulation of the problem of optimal control of shunt capacitor banks and Under Load Tap Changers located at HV/MV substations has been coupled with the optimal control of tie-switches and capacitor banks on the feeders of a large radially operated meshed distribution system with the aim of attaining minimum power losses and the flattening of the voltage profile. The considered formulation requires the optimization of two different objectives; therefore the use of adequate multiobjective heuristic optimization methods is needed. The heuristic strate…
Some improvements in solving radial distributions networks through the backward/forward method
2005
In the electrical radial distribution networks analysis, the backward/forward method shows good features in terms of robustness, independence from load nature, small use of hardware resources and limited calculation time. In the present paper, some procedures to improve the b/f method with the aim of reducing the calculation time are presented. The adopted procedures regard the choice of the initial values of the nodes voltages and the way in which the convergence criterion is applied. The results of some tests carried out on some electrical test systems here reported have shown the efficiency of the proposed methodology in terms of calculation time reduction, especially when solving heavil…
Frequency constrained optimal Power Flow based on Glow-worm Swarm Optimization in Islanded Microgrids
2015
This work presents an application of a swarm optimization method to solve the optimal power flow problem taking into account the constraints of frequency and line ampacity in three-phase islanded Microgrids. Each generation unit is equipped with a Power Electronics Interface. In the considered formulation, the droop control parameters are considered as variables to be adjusted by a higher control level, while the frequency is kept in rated bounds. Another typical constraint for OPF formulation, the max ampacity of each line, is also considered. Two case studies with different dimensions and electrical features have been considered and the obtained results show the efficiency of the proposed…
Optimal Sizing and Siting of Distributed Energy Resources Considering Public and Private Incentive Policies
2008
The present work presents the formulation and solution approach for the problem of optimal sizing and siting of distributed energy resources based on Photovoltaic, PV, technology. The considered system is an isolated grid (small island) and the parts involved are the utility and the customers. As it happens in islands, the same utility generates and delivers energy to customers, for this reason, the installation of dispersed generation units is beneficial for reducing power losses, regularizing the voltage profile, but also for increasing the profit. The problem is solved by means of the Non dominated sorting Genetic Algorithm II, NSGA-II, identifying the optimal size and location of PV sys…
Dynamic programming and Munkres algorithm for optimal photovoltaic arrays reconfiguration
2015
Abstract In this paper, an original formulation of the control problem for optimal PV array reconfiguration, following a Total Cross Tied layout, is proposed. The formulation follows the well-known subset sum problem, which is a special case of the knapsack problem. The reconfiguration is a measure devoted to mitigate the mismatch effect and maximize the output power of small photovoltaic plants under non-homogeneous working conditions. Therefore, reconfiguration means changing the connections of the solar panels adaptively by a dynamic switching matrix. The control system implements an easy dynamic programming algorithm to change the switches layout. The use of the Munkres assignment metho…
Driven Primary Regulation for Minimum Power Losses Operation in Islanded Microgrids
2018
The paper proposes an improved primary regulation method for inverter-interfaced generating units in islanded microgrids. The considered approach employs an off-line minimum losses optimal power flow (OPF) to devise the primary frequency regulation curve’s set-points while satisfying the power balance, frequency and current constraints. In this way, generators will reach an optimized operating point corresponding to a given and unique power flow distribution presenting the minimum power losses. The proposed approach can be particularly interesting for diesel-based islanded microgrids that face, constantly, the issue of reducing their dependency from fossil fuels and of enhancing their gener…
Hyers-Ulam Stability of a Nonlinear Volterra Integral Equation on Time Scales
2020
We study Hyers-Ulam stability of a nonlinear Volterra integral equation on unbounded time scales. Sufficient conditions are obtained based on the Banach fixed point theorem and Bielecki type norm.
Parked electric car's cabin heat management using photovoltaic powered ventilation system
2019
Abstract This paper explores the use of electric car roof mounted photovoltaic (PV) powered ventilation for cabin heat management/ventilation. A fully-functional Renault Zoe electric car has been used for performance evaluation of parked electric car ventilation directly powered by PV. This work has been part of a research project of testing electric cars in the urban environment and it has been conducted at the Edinburgh Napier University’s Transport Research Institute. In this work, parked electric car ventilation has been reported, when roof-mounted PV modules were used to operate DC powered fans for ventilation. It has been found that the DC motor-fan selection for removing the hot air …
Maximum Power Point Tracker for Standalone PV System Using Neural Networks
2019
In this work, designing and implementation of a maximum power point tracker (MPPT) based on an artificial neural network is proposed. The output voltage of the selected photovoltaic array is controlled by a DC to DC boost converter in a way that the PV array generates the available possible maximum power correspond to the available solar irradiance and temperature. The neural network (NN) is capable of forecasting the required terminal voltage of the PV array in order to generate the possible maximum power. The pulse width modulation (PWM) signal, which drives the boost converter, is generated through a raspberry pi according to the forecasted terminal voltage. The terminal voltage of the P…
Performance assessment of field deployed multi-crystalline PV modules in Nordic conditions
2019
This paper presents an investigation of data monitoring quality and evaluation of performance degradation of four different multi-crystalline silicon (mc-Si) photovoltaic (PV) modules installed in the higher latitude conditions in southern Norway. Degradation of each module has been investigated in terms of degradation of short-circuit current (I SC ), open-circuit voltage (V OC ), fill factor (FF) and maximum power (P MPP ). The analysis for the period of monitoring data from 2014 to 2018 show no considerable module degradation compared to the standard degradation rate of all parameters. The statistical analysis of I SC shows an average degradation of 0.17% for all modules. Spectral correc…