scholarly journals Determining the optimum medium voltage level by analysis of different voltage levels

2020 ◽  
Vol 10 (2) ◽  
pp. 37-49
Author(s):  
Fatma Avli Firis

Electric energy, which is the main input of the growing world economy, depending on the consumption of the rapidly increasing world population and the devices fed with this energy, have become more indispensable in our lives with each passing day. In the consumption of electrical energy, determining the voltage level plays an important role in planning distribution systems that will directly affect consumers. Distribution systems in our country have been established at different levels for technical and financial reasons. Incorrect choices that can be made during the determination of the voltage level in distribution systems may increase energy unit costs and network losses, and may cause insulation and reliability problems. The aim of this study is to determine the optimum voltage level in distribution systems. A pilot region was determined for a local electricity distribution network in our country, and modeling and analysis were carried out at different voltage levels in the region with the help of a numerical analysis program. According to the results achieved, Insulation and reliability problems at low voltages are few and economic in terms of investment costs, but it has been observed that the operating load and cost are high due to high network losses. In high voltages, although the operating burden and cost are relatively low, it has been observed that the investment costs are high and the isolation and reliability problems are high.   Keywords: cost; distribution; investment; operating ;Voltage

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1181
Author(s):  
Mitar Jocanovic ◽  
Boris Agarski ◽  
Velibor Karanovic ◽  
Marko Orosnjak ◽  
Milana Ilic Micunovic ◽  
...  

In this multidisciplinary research, an LCA/LCC model is developed for assessing the costs, energy consumption, and greenhouse gas (GHG) emissions during the pump unit lifecycles in drinking water distribution systems (WDS). The presented methodology includes the pump, motor, and variable frequency drive monitoring as a system (pump unit), through their life-cycle stages: the manufacturing stage, the exploitation stage, and the disposal stage at the end of their life-cycle. The developed model also analyses other processes such as the maintenance, testing, and reconstruction of the pump unit. Demonstration of the presented methodology was performed using the pump unit of an operating WDS system in different scenarios, in order to illustrate the proper application of this model. The obtained results show that the application of pump units is justified in terms of energy consumption. The results also show that 93%–94% of the consumed energy and the LCC costs are related to the pump operating costs, while the rest are related to auxiliary operations. The findings show that various countries can have considerably different prices of electrical energy and different GHG emissions that depend on the source of electric energy. The implemented model incorporates some of the symmetries that are commonly found in the mathematical models of water distribution systems. Finally, the results of pump unit exploitation within the WDS have been used to show the impact of such plants on different levels of energy consumption, GHG emissions, and LCC production.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1145 ◽  
Author(s):  
Ehsan Gord ◽  
Rahman Dashti ◽  
Mojtaba Najafi ◽  
Hamid Reza Shaker

: Fault location in electrical energy distribution networks is an important task, as faults in distribution grids are among the main causes of electricity supply disruption. Fault location in the distribution systems, however, is a challenging task because of the topology of the distribution networks, as well as the main and side branches. Therefore, it is necessary to address these challenges through an intelligent approach to fault location. In this paper, fault location in electric energy distribution networks is addressed considering the changes in fault distance and fault resistance in the presence of different fault types. A new method for fault location is developed for conditions where the minimum information is available and only information at the beginning of the feeder is used. This facilitates wide adoption of the technique as it does not require significant investments in instrumentation and measurement. The proposed intelligent method is based on the impedance and transient state estimation. This technique employs a specific impedance analysis for determining possible fault locations considering the unbalanced performance of distribution systems, distances, and different fault resistances. To determine the real faulty section, real fault frequency component analysis and the simulated faults at possible fault locations are used. At this stage of the process, it is possible to eliminate multiple estimations with the help of comparison and identification of the similarities. Therefore, a real faulty section is determined. It is observed that some conditions of electric energy distribution networks affect the accuracy and performance of the proposed method significantly; thus, a detailed investigation is conducted to neutralize these conditions. Simulation results and calculations based on MATLAB along with a practical test of the proposed method in power network simulator confirm a satisfactory performance.


2012 ◽  
Vol 16 (3) ◽  
pp. 131
Author(s):  
Didik Ariwibowo

Didik Ariwibowo, in this paper explain that energy audit activities conducted through several phases, namely: the initial audit, detailed audit, analysis of energy savings opportunities, and the proposed energy savings. Total energy consumed consists of electrical energy, fuel, and materials in this case is water. Electrical energy consumption data obtained from payment of electricity accounts for a year while consumption of fuel and water obtained from the payment of material procurement. From the calculation data, IKE hotels accounted for 420.867 kWh/m2.tahun, while the IKE standards for the hotel is 300 kWh/m2.tahun. Thus, IKE hotel included categorized wasteful in energy usage. The largest energy consumption on electric energy consumption. Largest electric energy consumption is on the air conditioning (AC-air conditioning) that is equal to 71.3%, and lighting and electrical equipment at 27.28%, and hot water supply system by 4.44%. Electrical energy consumption in AC looks very big. Ministry of Energy and Mineral Resources of the statutes, the profile of energy use by air conditioning at the hotel by 48.5%. With these considerations in the AC target for audit detail as the next phase of activity. The results of a detailed audit analysis to find an air conditioning system energy savings opportunities in pumping systems. Recommendations on these savings is the integration of automation on the pumping system and fan coil units (FCU). The principle of energy conservation in the pumping system is by installing variable speed drives (VSD) pump drive motor to adjust speed according to load on the FCU. Load variations FCU provide input on the VSD pumps to match. Adaptation is predicted pump can save electricity consumption up to 65.7%. Keywords: energy audit, IKE, AC


MRS Bulletin ◽  
1999 ◽  
Vol 24 (11) ◽  
pp. 40-44 ◽  
Author(s):  
R.B. Schwarz

Magnesium can reversibly store about 7.7 wt% hydrogen, equivalent to more than twice the density of liquid hydrogen. This high storage capacity, coupled with a low price, suggests that magnesium and magnesium alloys could be advantageous for use in battery electrodes and gaseous-hydrogen storage systems. The use of a hydrogen-storage medium based on magnesium, combined with a fuel cell to convert the hydrogen into electrical energy, is an attractive proposition for a clean transportation system. However, the advent of such a system will require further research into magnesium-based alloys that form less stable hydrides and proton-conducting membranes that can raise the operating temperature of the current fuel cells.Following the U.S. oil crisis of 1974, research into alternative energy-storage and distribution systems was vigorously pursued. The controlled oxidation of hydrogen to form water was proposed as a clean energy system, creating a need for light and safe hydrogen-storage media. Extensive research was done on inter-metallic alloys, which can store hydrogen at densities of about 1500 cm3-H2 gas/ cm3-hydride, higher than the storage density achieved in liquid hydrogen (784 cm3/cm3 at –273°C) or in pressure tanks (˜200 cm3/cm3 at 200 atm). The interest in metal hydrides accelerated following the development of portable electronic devices (video cameras, cellular phones, laptop computers, tools, etc.), which created a consumer market for compact, rechargeable batteries. Initially, nickel-cadmium batteries fulfilled this need, but their relatively low energy density and the toxicity of cadmium helped to drive the development of higher-energy-density, less toxic, rechargeable batteries.


2015 ◽  
Vol 77 (21) ◽  
Author(s):  
Jazli Firdaus Jamil ◽  
Mohd Azman Abdullah ◽  
Norreffendy Tamaldin ◽  
Ahmed Esmael Mohan

The world is demanding for alternative way of energy consumption for vehicle usage. The energy efficient vehicle (EEV) is one of the advancement for future land transportation that known as hybrid and electric vehicles nowadays. The vehicles use different energy other than fuel which is electric energy. This paper emphasizes the development of electromagnetic energy regenerative suspension system (EReSS) as a system that harvests energy from the vibration of vehicle suspension system. The harvested energy is converted to electrical energy for vehicle usage. A prototype of electromagnetic EReSS is fabricated and laboratory experimentation on test rig is conducted to test the voltage output. It is observed that the EReSS can harvest the wasted energy from the vibration and produce sufficient electric energy for the vehicle electrical and electronic usage. The number of windings of the coil and diameter of the coil affect the voltage output of the EReSS. The voltage output of the EReSS can be optimized by setting up the parameters. As the EReSS is proven to harvest energy, it can be used on hybrid and electric vehicle to improve the efficiency of the vehicle and reduce the fuel consumption.


2014 ◽  
Vol 29 (spe) ◽  
pp. 31-40 ◽  
Author(s):  
Ana Paula Paes dos Santos ◽  
José Ricardo Santos de Souza ◽  
Everaldo Barreiros de Souza ◽  
Alexandre de Melo Casseb do Carmo ◽  
Wanda Maria do Nascimento Ribeiro

Operational records of power outages of the electric energy distribution systems in eastern Amazonia presented a large number of events attributed to lightning strikes, during the 2006 to 2009 period. The regional electricity concessionary data were compared to actual lightning observations made by SIPAM's LDN system, over two areas where operational sub systems of transmission lines are installed. Statistical relations were drawn between the monthly lightning occurrence density and the number of power outages of the electric systems for both areas studied. The results showed that, although with some delays between these variables peaks, the number of power disruptions has a tendency to follow the behavior of the lightning occurrence densities variations. The numerical correlations were positive and may be useful to the transmission lines maintenance crews at least for the Belém-Castanhal electricity distribution sub system. Evidence was found, that the SST's over certain areas of the Pacific and Atlantic Oceans, influence convection over the area of interest, and may help to prognosticate the periods of intense electric storms, requiring repair readiness for the regional electric systems.


Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7364
Author(s):  
Yi-Ren Wang ◽  
Ming-Ching Chu

This research proposes an energy harvesting system that collects the downward airflow from a helicopter or a multi-axis unmanned rotary-wing aircraft and uses this wind force to drive the magnet to rotate, generating repulsive force, which causes the double elastic steel system to slap each other and vibrate periodically in order to generate more electricity than the traditional energy harvesting system. The design concept of the vibration mechanism in this study is to allow the elastic steel carrying the magnet to slap another elastic steel carrying the piezoelectric patch to form a set of double elastic steel vibration energy harvesting (DES VEH) systems. The theoretical DES VEH mechanism of this research is composed of a pair of cantilever beams, with magnets attached to the free end of one beam, and PZT attached to the other beam. This study analyzes the single beam system first. The MOMS method is applied to analyze the frequency response of this nonlinear system theoretically, then combines the piezoelectric patch and the magneto-electric coupling device with this nonlinear elastic beam to analyze the benefits of the system’s converted electrical energy. In the theoretical study of the DES VEH system, the slapping force between the two elastic beams was considered as a concentrated load on each of the beams. Furthermore, both SES and DES VEH systems are studied and correlated. Finally, the experimental data and theoretical results are compared to verify the feasibility and correctness of the theory. It is proven that this DES VEH system can not only obtain the electric energy from the traditional SES VEH system but also obtain the extra electric energy of the steel vibration subjected to the slapping force, which generates optimal power to the greatest extent.


Author(s):  
Marija D. Ilic ◽  
Pedro M. S. Carvalho

We propose to conceptualise electric energy systems as complex dynamical systems using physically intuitive multilayered energy modelling as the basis for systematic diverse technology integration, and control in on-line operations. It is shown that such modelling exhibits unique structure which comes from the conservation of instantaneous power (P) and of instantaneous reactive power ( _Q), (interaction variables (intVar)) at the interfaces of subsystems. The intVars are used as a means to model and control the interactive zoomed-out inter-modular (inter-area, inter-component) system dynamics. Control co-design can then be pursued using these models so that the primary control shapes intVars of its own module by using its own lowlevel detailed technology-specific model and intVar info exchange with the neighbours. As a result, we describe how the proposed approach can be used to support orderly evolution from today’s hierarchical control to a platform enabling flexible interactive protocols for electricity services. The potential for practical use of the proposed concepts is far-reaching and transparent. All that needs to be conceived is that intVar characterising any intelligent Balancing Authority (iBA) is a generalisation of today’s Area Control Error (ACE) characterising net energy balance of a Balancing Authority (BA). An iBA can be any subsystem with its own sub-objectives, such as distributed energy resources (DERs) comprising customers and grid forming microgrids; distribution systems; transmission systems; Independent System Operators (ISOs); and, ultimately, electric energy markets within large interconnection. Several industry problems are described as particular sub-problems of general interactive electricity services. These formulations help one compare models and assumptions used as part of current solutions, and propose enhanced solutions. Most generally, feasibility and stability conditions can be introduced for ensuring feasible power flow solutions, regulated frequency and voltage and orderly power exchange across the iBAs.


Sign in / Sign up

Export Citation Format

Share Document