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This paper proposes a practical time-phased model to analyze the vulnerability of power systems over a time horizon, in which the scheduled maintenance of network facilities is considered. This model is deemed as an efficient tool that could be used by system operators to assess whether how their systems become vulnerable giving a set of scheduled facility outages. The final model is presented as...
Hierarchical learning as another way to scale up reinforcement learning and enable its applications to very hard learning problems. Hierarchical learning is a divide-and-conquer technique a complex learning problem is decomposed into small pieces so that they can be easily solved. The option framework is one way to using hierarchical learning in reinforcement learning. In this paper we have used the...
One of the major issues in smart grid monitoring, protection and power quality event identification is accurate phasor estimation. Proper phasor estimation is more important especially during fault, because the signals doesn’t have pure sine wave anymore and include different harmonic components and Decaying DC offset, so Proper phasor estimation in smart grids are very important issue. This paper...
This paper presents a control scheme based on fractional proportional-integral controller for improving the load sharing among parallel-connected inverter based distributed generation in microgrid. The control context is based on the current control in which through the use of the proposed strategy dynamically preserves the proportional power sharing properties of the DG units. The results show that...
Finding minimum number of connecting lines is as important as locating phasor measurement units (PMUs) for full observability of power system. Therefore, a PMU placement method should determine both optimum buses and lines, since utilities can make better decisions for monitoring of power system with this information. Moreover, it is necessary to provide direct observation of critical buses and transmission...
Energy consumption in battery-based nodes and network traffic optimization are two main challenges associated with wireless sensor networks and the traditional digital control architecture is not optimized from these perspectives. Thus, using optimal control theory and event-based control concept, we propose a novel architecture to tackle the regulation and tracking problems in wireless sensor networks...
In this paper, a new dynamic model for the investment process in the power system, including renewable energy sources is proposed. In this regard, three thermal units including base, intermediate and peak load technologies with wind turbine generators have been considered. In the proposed framework, the uncertainty of the thermal units due to their outages as well as the uncertainty of wind power...
Increasing redundant paths in transmission grids has always been thought to be a tool to enhance service reliability. However, network equations by intertwining power flows through redundant paths impose more limits on systems with more redundancy. Accordingly, autonomous removing of a few lines may relief capacity limit violations in some contingency events thereby enhancing service reliability....
Broadband signal transmission through communication channels in home environments is one of the interesting topics in the field of intelligent buildings. Building designers are interested in transferring multimedia content with minimum cost, energy consumption, and acceptable quality. Limitations and drawbacks of existing transmission systems such as coaxial cable, wireless transmission, etc., have...
Recently, the development of Microgrids (MGs) causes challenges that need considerable attention. One of the most challenging problems which occurs when a MG is islanding or disconnecting from the main grid, since during this event frequency and voltage of MG deviate from their nominal values. Energy Storage Systems (ESSs) are used to solve this problem. In this paper, Flywheel Energy Storage System...
Microgrids are defined as power systems, which have small scale and low voltage level. Isolated and remote areas, small loads and places are usually faced with problem of lack of accessibility to main power grid. Microgrids can be an appropriate choice for these areas regarding to environmental and economic aspects. These grids are appropriate to meet various kinds of loads such as domestic, industrial...
This paper investigates three different strategies for centralized charging/discharging management of electric vehicles, their features and the impacts on technical performance of distribution systems. Three goals of load factor maximization, load variance reduction and energy loss minimization are chosen as the main technical factors need to be optimized in the proposed electric vehicles charging/discharging...
Microgrid provides distributed generations and households in a low-voltage network which can either be isolated or transport power to the other networks. This paper aims to help a microgrid control center to find the optimal day-ahead scheduling for its components. The optimal schedule comprises switching controllable appliances and distributed generations and determining the optimum value of input...
In this work, we carry out a exact performance analysis of dual-hop cooperative amplify-and-forward relaying systems in wireless body area networks over independent and nonidentically distributed Gamma fading channels. In particular, we derive new exact closed-form expressions for the end-to-end outage and symbol error probabilities at arbitrary signal-to-noise-ratios (SNRs) of these systems in terms...
This study proposes an effective analyticalheuristic approach for solving optimal placement and sizing of multiple distributed generator problem to achieve a high loss reduction in large-scale distribution network. Proposed analytical- heuristic method (AHM) is based on improvement of LSF (loss sensitivity factor) method. AHM utilizes PSO (particle swarm optimization) algorithm to find the optimal...
Plug-in hybrid electric vehicles (PHEVs) are considered as a promising solution to resolve global warming. In order to assess the impact of PHEV’s charging on distribution systems, their demand needs to be accurately predicted, especially for planning and operation studies. In this paper, a Monte Carlobased algorithm is proposed for PHEV demand modeling. Home arrival time, traveled distance, and home...
This paper presents a control approach for improving transient behavior of an autonomous inverter-based microgrid employing secondary controller. A feed-forward loop is utilized to enhance the characteristics of active and reactive power responses. This stage is implemented in power controller section. It can be proved that this approach has the capability of improving the stability of microgrid using...
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