Evaluation of Continuous Power-Down Schemes

We consider a power-down system with two states—“on” and “off”—and a continuous set of power states. The system has to respond to requests for service in the “on” state and, after service, the system can power off or switch to any of the intermediate power-saving states. The choice of states determines the cost to power on for subsequent requests. The protocol for requests is “online”, which means that the decision as to which intermediate state (or the off-state) the system will switch has to be made without knowledge of future requests. We model a linear and a non-linear system, and we consider different online strategies, namely piece-wise linear, logarithmic and exponential. We provide results under online competitive analysis, which have relevance for the integration of renewable energy sources into the smart grid. Our analysis shows that while piece-wise linear systems are not specific for any type of system, logarithmic strategies work well for slack systems, whereas exponential systems are better suited for busy systems.

Grid-Connected Inverter for a PV-Powered Electric Vehicle Charging Station to Enhance the Stability of a Microgrid

This study proposes a grid-connected inverter for photovoltaic (PV)-powered electric vehicle (EV) charging stations. The significant function of the proposed inverter is to enhance the stability of a microgrid. The proposed inverter can stabilize its grid voltage and frequency by supplying or absorbing active or reactive power to or from a microgrid using EVs and PV generation. Moreover, the proposed inverter can automatically detect an abnormal condition of the grid, such as a blackout, and operate in the islanding mode, which can provide continuous power to local loads using EV vehicle-to-grid service and PV generation. These inverter functions can satisfy the requirements of the grid codes, such as IEEE Standard 1547–2018 and UL 1741 SA. In addition, the proposed inverter can not only enhance the microgrid stability but also charge EVs in an appropriate mode according to the condition of the PV array and EVs. The proposed inverter was verified through experimental results with four scenarios in a lab-scale testbed. These four scenarios include grid normal conditions, grid voltage fluctuations, grid frequency fluctuations, and a power blackout. The experimental results demonstrated that the proposed inverter could enhance the microgrid stability against grid abnormal conditions, fluctuations of grid frequency and voltage, and charge EVs in an appropriate mode.

Corrosion Behavior in Volcanic Soils: In Search of Candidate Materials for Thermoelectric Devices

Thermoelectric generators have emerged as an excellent solution for the energy supply of volcanic monitoring stations due to their compactness and continuous power generation. Nevertheless, in order to become a completely viable solution, it is necessary to ensure that their materials are able to resist in the acidic environment characteristic of volcanoes. Hence, the main objective of this work is to study the resistance to corrosion of six different metallic materials that are candidates for use in the heat exchangers. For this purpose, the metal probes have been buried for one year in the soil of the Teide volcano (Spain) and their corrosion behavior has been evaluated by using different techniques (OM, SEM, and XRD). The results have shown excessive corrosion damage to the copper, brass, and galvanized steel tubes. After evaluating the corrosion behavior and thermoelectric performance, AISI 304 and AISI 316 stainless steels are proposed for use as heat exchangers in thermoelectric devices in volcanic environments.

Successful Zonal Isolation in Complex Fractured Carbonate Scenario Using Thixotropic Gel and Hybrid Electric-Fiber Cable Coiled Tubing Technology

Water production has always afflicted mature fields due to the uneconomical nature of high water cut (WC) wells and the high cost of water management. Rigless coiled tubing (CT) interventions with increasingly articulated operating procedures are the key to a successful water reduction. In the scenario presented in this paper, high technological through tubing water shut off (WSO) for a long horizontal open hole (OH) well in a naturally fractured carbonate reservoir leads the way to new opportunities of production optimization. Engineering phase included sealant fluid re-design: the peculiar well architecture and fracture systems led to the customization of a sealant gel by modifying its rheological properties through laboratory tests, to improve effectiveness of worksite operations. A new ad-hoc procedure was defined, with a new selective pumping and testing technique tailored to each drain fracture. The use of Real-Time Hybrid Coiled Tubing Services (CT with fiber optic system coupled with real time capabilities of an electric cable) made it possible to optimize intervention reliability. Details of the operating procedure are given, with the aim of ensuring a successful outcome of the overall treatment Sealing gels are effective in plugging the formation, but in fractured environments the risk of losing the product before it starts to build viscosity is high. The success of the water shut off job has been obtained by using specific gel with thixotropic properties for an effective placement. In addition, the pumping has been performed in steps, each followed by a pressure test to assess the effectiveness of the plugging. Results are compared to two past interventions with equal scope in the same well: a first one with high volume of gel and an unoptimized pumping technique through CT and a second where a water reactive product was pumped by bullheading. The selective and repetitive approach pumping multiple batches of sealant system with CT stationary in front of a single fracture provided the best results from all three techniques. The real-time bottom hole data reading capability provided by hybrid CT allowed the placement of thru tubing bridge plugs (BP) with high accuracy and confidence with the ability to set electrically, therefore reducing risks related to hydraulic setting tools (i.e. premature setting). This also allows continual pumping during the run in hole (RIH) to clean up the zone prior to setting the BP. The combination of this innovative pumping technique and customization of the sealant fluid made it possible to achieve unprecedented water reduction in the field. The high technology CT supported the operation by providing continuous power and telemetry to the bottom hole assembly (BHA) for real time (RT) downhole diagnostics. Moreover, the operating procedures offer basic guidelines to successfully perform water shut off jobs in any other reservoir independent of its geological nature and structure.

Procedure for calculation of the admissible continuous power transmission currents of overhead wires and contact lines

The proposed methodology summarizes published and original domestic and foreign theoretical and experimental materials on heating and cooling of spiral and shaped wires of overhead power transmission lines and electric power systems and uses those of them that best meet the fundamental laws of heat transfer. Formulas for calculating the surface area for spiral and shaped wires are given. A generalized formula for the convective heat transfer coefficient taking into account the direction and speed of the wind, including for the anti-ice regime, is given. The parameters of this formula do not coincide with the existing ones, since they are based on the experimental data for spiral and shaped wires, and not for round pipes. The formula for calculating the power of heat transfer under solar radiation is given. A generalized formula is given for calculating the continuous allowable current, all components of which are described in detail in the article.

Analysis of Potential and Feasibility of Hydropower Energy from Sepaku Semoi Dam in Penajam Paser Utara Regency

This paper will present a techno-economic potential and feasibility analysis in the planning of renewable hydropower energy from Sepaku Semoi Dam in Penajam Paser Utara (PPU) Regency. The dam was planned to be built to support the water needs of Indonesia’s prospective capital. The analysis was done based on the last twenty years’ rainfall intensity data history from Sepaku rain station and Sepinggan rain station and digital elevation model (DEM) from DEMNAS with support of the river basin agency of Kalimantan Timur. The result of dependable discharge calculation of Sepaku Semoi river using FJ Mock Method is 2.45 m/s2. And the head of the hydropower power plant is 15.85 meters. The total potential electricity generated from hydropower reached 2,593,140 kWh/year. The assessment of feasibility indicators in this research took into account the technology and economic aspects. The technology aspects help evaluate the technical planning of installations that are possible to build in the dam. The economic aspect of feasibility evaluates the net present value (NPV), internal rate of return (IRR), and the payback period of renewable energy installation. This analysis aimed to get a comprehensive insight from the potential hydropower energy that exists at the research locations and conduct a feasibility study based on techno-economic analysis to develop renewable energy. The results showed that 15.85 meters had the most significant potential of hydropower by generating 290 kW continuous power with a feed-in tariff of 0.054 USD/kWh. The electricity was feasible to offer to the government electrical company. Moreover, this project had a payback period of 8 years, and NPV of 64,005 USD, and an IRR Project of 11.86%.

Optimization of an automatic voltage regulator AVR on a synchronous machine using fuzzy control

The constantly developing society demands more and more electronic devices and microchips that perform vital tasks such as medical services, emergency lighting, communication systems, among others, however these are sensitive to variations and failures of the power supply, such as voltage fluctuations, voltage spikes and interference, for this reason and because of its great importance for its proper functioning must have a continuous power supply, Thus, the work shown in this article proposes to optimize the operation of automatic voltage correction devices AVR used in synchronous power generating machines whose main function is to ensure that the voltage has been constant, for this a solution is proposed based on the use of non-traditional control techniques such as fuzzy logic, For this purpose initially recognizes the relevant elements that make up the AVR system which are amplifier, exciter, generator and sensor then illustrates the mathematical block model that represents the operation of the system which is reduced to transfer function or otherwise as the relationship of the input and output signal of the system, Then a possible classical PID proportional integral derivative proportional control is suggested with the help of the PID tools of the software Matlab ®, where the fuzzy logic inference set is programmed in three stages: first stage: input of the set of rules for voltage error correction, second stage: input of the set of rules for the voltage field output in the synchronous machine, and in a third stage: programming of the fuzzy inference sentences. Finally, the response of each control is compared and the methodology in the design of the alternative control in the synchronous machine is exposed, with the use of the software Matlab®, all this as a study of new trends in control for educational purposes, in the context of Technology in Electricity and Electronic Technology.

Power Management of Hybrid Grid System With Battery Deprivation Cost Using Artificial Neural Network

Continuous power supply in an integrated electric system supplied by solar energy and battery storage can be optimally maintained with the use of diesel generators. This article discusses the optimum setting-point for isolated wind, photo-voltaic, diesel, and battery storage electric grid systems. Optimal energy supply for hybrid grid systems means that the load is sufficient for 24 h. This study aims to integrate the battery deprivation costs and the fuel price feature in the optimization model for the hybrid grid. In order to count charge–discharge cycles and measure battery deprivation, the genetic algorithm concept is utilized. To solve the target function, an ANN-based algorithm with genetic coefficients can also be used to optimize the power management system. In the objective function, a weight factor is proposed. Specific weight factor values are considered for simulation studies. On the algorithm actions, charging status, and its implications for the optimized expense of the hybrid grid, the weight factor effect is measured.

Design and Simulation of Hybrid Solar PV-Fuel-Cell-Battery System to supply in the Nit Kurukshetra Campus and its effect on the Environment using Homer Software

The main objective of this paper is to design a hybrid power system for continuous power supply in the institute campus nit Kurukshetra in an economical way to replace the external grid power system. In this paper solar photovoltaic Fuel cell battery hybrid system has been studied. Costing, sizing, optimization, and simulation were done using the software homer pro. The Levelized Cost of electricity (COE) is Rs. 11.12 per KW is obtained and the system is based on renewable energy sources so it sustainably generates electricity.