Current Issue : January-March Volume : 2023 Issue Number : 1 Articles : 5 Articles
Photovoltaic (PV) systems are dependent on solar irradiation and environmental temperature to achieve their best performance. One of the challenges in the photovoltaic industry is performing maintenance as soon as a system is not working at its full generation capacity. The lack of a proper maintenance schedule affects power generation performance and can also decrease the lifetime of photovoltaic modules. Regarding the impact of environmental variables on the performance of PV systems, research has shown that soiling is the third most common reason for power loss in photovoltaic power plants, after solar irradiance and environmental temperature. This paper proposes a new statistical predictor for forecasting PV power generation by measuring environmental variables and the estimated mass particles (soiling) on the PV system. Our proposal was based on the fit of a nonlinear mixed-effects model, according to a log-logistic function. Two advantages of this approach are that it assumes a nonlinear relationship between the generated power and the environmental conditions (solar irradiance and the presence of suspended particulates) and that random errors may be correlated since the power generation measurements are recorded longitudinally. We evaluated the model using a dataset comprising environmental variables and power samples that were collected from October 2019 to April 2020 in a PV power plant in mid-west Brazil. The fitted model presented a maximum mean squared error (MSE) of 0.0032 and a linear coefficient correlation between the predicted and observed values of 0.9997. The estimated average daily loss due to soiling was 1.4%....
Today, many industrial and domestic electronic appliances and equipment (devices) are exposed to power disturbances such as voltage variations of the AC mains supply which often lead to damage of the electronic devices. As these devices are quite sensitive to power disturbances, there is a need for a tripping system that can help avoid any damage to devices in use. The objective of this work is to build a system that monitors line voltage and protects appliances from unacceptable voltage variations. The system consists of a tripping mechanism that monitors the input voltage and trips according to the limits provided. An Arduino Uno microcontroller is used to determine the voltage level through a voltage divider circuit. The system’s novelty and innovation lie in its flexibility. It offers the user the ability to define different overvoltage and undervoltage threshold values depending on the specific appliances used in the household. In operation, the system displays the voltage state (overvoltage, normal voltage, overvoltage) and alerts the user by sending an SMS via a GSM modem. The system is valuable for industrial and domestic applications, especially in developing economies such as those of Sub-Saharan Africa, where overvoltage and undervoltage are acute problems....
In this paper, we consider the distributed power tracking and energy balancing problem of a general energy storage system subject to unreliable switching communication network. In order to deal with the uncertainty of the network topology, a distributed observer-based approach has been proposed. First, an adaptive distributed observer is employed to recover the reference power for the entire energy storage system for each energy storage unit. Second, based on the estimated reference power, a certainty equivalent control law is synthesized to simultaneously achieve power tracking and energy balancing. Numerical simulations are provided to validate the proposed control approach....
This research proposes a synergistic meta-heuristic algorithm for solving the extreme operational complications of combined heat and power economic dispatch problem towards the advantageous economic outcomes on the cost of generation. The combined heat and power (CHP) is a system that provides electricity and thermal energy concurrently. For its extraordinary efficiency and significant emission reduction, it is considered a promising energy prospect. The broad application of combined heat and power units requires the joint dispatch of power and heating systems, in which the modelling of combined heat and power units plays a vital role. The present research employs the genetic optimization algorithm to evaluate the cost function, heat and power dispatch values encountered in a system with simple cycle cogeneration unit and quadratic cost function. The system was first modeled to determine the various parameters of combined heat and power units towards solving its economic dispatch problem directly. In order for modelling to be done, a general structure of combined heat and power must be defined. The test system considered consists of four units: two conventional power units, one combined heat and power unit and one heat-only unit. The algorithm was applied to test system while taking into account the power and heat units, bounds of the units and feasible operation region of cogeneration unit. Output decision variables of 4-unit test systems plus cost function from Genetic Algorithm (GA), was determined using appropriate codes. The proposed algorithm produced a well spread and diverse optimal solution and also converged reasonably to the actual optimal solution in 51 iterations. The result obtained compared favourably with that obtained with the direct solution algorithm discussed in a previous paper. We conclude that the genetic algorithm is quite efficient in dealing with non-convex and constrained combined heat and power economic dispatch problem....
An analysis for a conceptual design of a thermal power plant (with a power capacity of 1 GW) is provided. This power plant can help in meeting the expected increase in the electric demand for Oman’s dominant power system (2.4 GW between 2018 and 2025). A necessary fluid mass flow rate of 834.1 kg/s was predicted. The overall energy conversion efficiency (output useful electricity divided by input heat) was estimated to be 34.7%. The needed thermal energy is not restricted to a specific source, and solar heating is an option for supplying the needed heat. The power plant design is based on using a steam-turbine section, which may be composed of a single large steam turbine having a mechanical power output of 1115 MW; or composed of a group of smaller steam turbines. The analysis is based on applying energy balance equations under certain assumptions (such as neglecting changes in potential energy). The thermal analysis was aided by web-based tool for calculating needed properties of the working medium, which is water, at different stages in the power plant....
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