Search results for: Direct Power Control (DPC)

Authors: S. Murugan, Bohumil Horak

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Pyrolysis is one of the possible technologies to derive energy from waste organic substances. In recent years, pilot level and demonstrated plants have been installed in few countries. The heat energy lost during the process is not effectively utilized resulting in less savings of energy and money. This paper proposes a novel approach to integrate a combined heat and power unit(CHP) and reduce the primary energy consumption in a tyre pyrolysis pilot plant. The proposal primarily uses the micro combined heat and power concept that will help to produce both heat and power in the process.

Keywords: pyrolysis, waste tyres, waste plastics, biomass, waste heat

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Authors: Victor Siahaan

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Coal still become the most important energy source for electricity generation known for its contribution which take the biggest portion of energy mix that a country has, for example Indonesia. The low cost of electricity generation and quite a lot of resources make this energy still be the first choice to fill the portion of base load power. To realize its significance to produce electricity, it is necessary to know the amount of coal (volume) needed to ensure that all coal power plants (CPP) in a country can operate properly. To secure the volume of coal, in this study, discussion was carried out regarding the identification of coal mining sources in Indonesia, classification of coal typical from each coal mining sources, and determination of the port of loading. By using data above, the sources of coal mining are then selected to feed certain CPP based on the compatibility of the coal typical and the lowest transport cost.

Keywords: merit order, Indonesian coal mine, electricity, power plant

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Authors: Kusum Tharani, Ratna Dahiya

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This paper aims to analyze the power flow of a grid connected 100-kW Photovoltaic(PV) array connected to a 25-kV grid via a DC-DC boost converter and a three-phase three-level Voltage Source Converter (VSC). Maximum Power Point Tracking (MPPT) is implemented in the boost converter bymeans of a Simulink model using the 'Perturb & Observe' technique. First, related papers and technological reports were extensively studied and analyzed. Accordingly, the system is tested under various loading conditions. Power flow analysis is done using the Newton-Raphson method in Matlab environment. Finally, the system is subject to Single Line to Ground Fault and Three Phase short circuit. The results are simulated under the grid-connected operating model.

Keywords: grid connected PV Array, Newton-Raphson Method, power flow analysis, three phase fault

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Authors: Mariela Gonzalez, Zoraide Lugli, Eleonora Vivas, Rosana Guzmán

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The objective was to determine the predictive capacity of self-efficacy perceived for weight control, locus of weight control and skills of weight self-management in the dissatisfaction of the body image in obese people who attend treatment. Sectional study conducted in the city of Maracay, Venezuela, with 243 obese who attend to treatment, 173 of the feminine gender and 70 of the male, with ages ranging between 18 and 57 years old. The sample body mass index ranged between 29.39 and 44.14. The following instruments were used: The Body Shape Questionnaire (BSQ), the inventory of body weight self-regulation, The Inventory of self-efficacy in the regulation of body weight and the Inventory of the Locus of weight control. Calculating the descriptive statistics and of central tendency, coefficients of correlation and multiple regression; it was found that a low ‘perceived Self-efficacy in the weight control’ and a high ‘Locus of external control’, predict the dissatisfaction with body image in obese who attend treatment. The findings are a first approximation to give an account of the importance of the personal control variables in the study of the psychological grief on the overweight individual.

Keywords: dissatisfaction with body image, obese people, personal control, psychological variables

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Authors: Bauer Peter, Murillo Jenny

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This paper investigates the bounds of achievable fuel efficiency improvements in engines due to cycling between two operating points assuming a series hybrid configuration . It is shown that for linear bsfc dependencies (as a function of power), cycling is only beneficial if the average power needs are smaller than the power at the optimal bsfc value. Exact expressions for the fuel efficiency gains relative to the constant output power case are derived. This asymptotic analysis is then extended to the case where transient losses due to a change in the operating point are also considered. The case of the boundary bsfc trajectory where constant power application and cycling yield the same fuel consumption.is investigated. It is shown that the boundary bsfc locations of the second non-optimal operating points is hyperbolic. The analysis of the boundary case allows to evaluate whether for a particular engine, cycling can be beneficial. The introduced concepts are illustrated through a number of real world examples, i.e. large production Diesel engines in series hybrid configurations.

Keywords: cycling, efficiency, bsfc, series hybrid, diesel, operating point

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Authors: Shun Horikoshi, Tohru Kawabe

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This study presents performance analysis results of SMC (Sliding mode control) with changing the chattering functions applied to slip suppression problem of electric vehicles (EVs). In SMC, chattering phenomenon always occurs through high frequency switching of the control inputs. It is undesirable phenomenon and degrade the control performance, since it causes the oscillations of the control inputs. Several studies have been conducted on this problem by introducing some general saturation function. However, study about whether saturation function was really best and the performance analysis when using the other functions, weren’t being done so much. Therefore, in this paper, several candidate functions for SMC are selected and control performance of candidate functions is analyzed. In the analysis, evaluation function based on the trade-off between slip suppression performance and chattering reduction performance is proposed. The analyses are conducted in several numerical simulations of slip suppression problem of EVs. Then, we can see that there is no difference of employed candidate functions in chattering reduction performance. On the other hand, in slip suppression performance, the saturation function is excellent overall. So, we conclude the saturation function is most suitable for slip suppression sliding mode control.

Keywords: sliding mode control, chattering function, electric vehicle, slip suppression, performance analysis

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Authors: Joaquim Rubens Fontes-Filho, Felipe Buchbinder, Marcelo Desterro

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The study aims to identify the effects of an economic recession on the compensation of executives of listed companies. Market-based and labor environment explanations have received particular attention, both to explain the reasons for a growth in this compensation and to indicate that they may increase agency problems rather than mitigate them. In this sense, labor forces, especially related to the market for executives, contribute to defining the terms of compensation packages and represent a significant external control mechanism to moderate agency problems, but may be of little effect if the executives are entrenched and concentrate enough power to have a say in his/her compensation. Based on a five-year data panel related to executive compensation in 250 listed companies in Brazil, we examine whether the economic recession in the last two years produced any impact in this compensation, controlling for the sector and level of governance of the company.

Keywords: agency problems, executive compensation, control mechanisms, corporate governance

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Authors: Prangvalai Buasan, Boonrod Sajjakulnukit, Thongchart Bowonthumrongchai

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The demand for biomass pellets in the industrial sector has significantly increased since 2020. The revised version of Thailand’s power development plan as well as the Alternative Energy Development Plan, aims to promote biomass fuel consumption by around 485 MW by 2030. The replacement of solid fossil fuel with biomass pellets will affect medium-term and long-term national benefits for all industries throughout the supply chain. Therefore, the evaluation of environmental and economic impacts throughout the biomass pellet supply chain needs to be performed to provide better insight into the goods and financial flow of this activity. This study extended the national input-output table for the biomass pellet industry and applied the input-output analysis (IOA) method, a sort of macroeconomic analysis, to interpret the result of transactions between industries in the monetary unit when the revised national power development plan was adopted and enforced. Greenhouse gas emissions from consuming energy and raw material through the supply chain are also evaluated. The total intermediate transactions of all economic sectors, which included the biomass pellets sector (CASE 2), increased by 0.02% when compared with the conservative case (CASE 1). The control total, which is the sum of total intermediate transactions and value-added, the control total of CASE 2 is increased by 0.07% when compared with CASE 1. The pellet production process emitted 432.26 MtCO2e per year. The major sharing of the GHG is from the plantation process of raw biomass.

Keywords: input-output analysis, environmental extended input-output analysis, macroeconomic planning, biomass pellets, renewable energy

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Authors: Nur Ashida Salim, Muhammad Murtadha Othman, Ismail Musirin, Mohd Salleh Serwan

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Uncertainty of system operating conditions is one of the causative reasons which may render to the instability of a transmission system. This will encumber the performance of transmission system to efficiently transmit the electrical power between areas. For that reason, accurate assessment of Transmission Reliability Margin (TRM) is essential in order to ensure effective power transfer between areas during the occurrence of system uncertainties. The power transfer is also called as the Available Transfer Capability (ATC) in which it is the information required by the utilities and marketers to instigate selling and buying the electric energy. This paper proposes a computationally effective approach to estimate TRM and ATC by considering the uncertainties of system cascading collapse and transmission line outages which is identified as the main reasons in power system instability. In accordance to the results that have been obtained, the proposed method is essential for the transmission providers which could help the power marketers and planning sectors in the operation and reserving transmission services based on the ATC calculated.

Keywords: system cascading collapse, transmission line outages, transmission reliability margin, available transfer capability

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Authors: W. Hashim, H. Burok, N. Ghazaly, H. Ahmad Nasir, N. Mohamad Anas, A. F. Ismail, K. L. Yau

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Future communication networks require devices that are able to work on a single platform but support heterogeneous operations which lead to service diversity and functional flexibility. This paper proposes two cognitive mechanisms termed cognitive hybrid function which is applied in multiple broadband user terminals in order to maintain reliable connectivity and preventing unnecessary interferences. By employing such mechanisms especially for future hyper-dense network, we can observe their performances in terms of optimized speed and power saving efficiency. Results were obtained from several empirical laboratory studies. It was found that selecting reliable network had shown a better optimized speed performance up to 37% improvement as compared without such function. In terms of power adjustment, our evaluation of this mechanism can reduce the power to 5dB while maintaining the same level of throughput at higher power performance. We also discuss the issues impacting future telecommunication standards whenever such devices get in place.

Keywords: dense network, intelligent network selection, multiple networks, transmit power adjustment

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Authors: Badr M. Alshammari, T. Guesmi

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In recent years, the combined economic and emission power dispatch is one of the main problems of electrical power system. It aims to schedule the power generation of generators in order to minimize cost production and emission of harmful gases caused by fossil-fueled thermal units such as CO, CO₂, NO_x, and SO₂. To solve this complicated multi-objective problem, an improved version of the particle swarm optimization technique that includes non-dominated sorting concept has been proposed. Valve point loading effects and system losses have been considered. The three-unit and ten-unit benchmark systems have been used to show the effectiveness of the suggested optimization technique for solving this kind of nonconvex problem. The simulation results have been compared with those obtained using genetic algorithm based method. Comparison results show that the proposed approach can provide a higher quality solution with better performance.

Keywords: power dispatch, valve point loading effects, multiobjective optimization, Pareto solutions

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Authors: Haleh Hamidpour

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Since the seismic damageability of structures is controlled by the inelastic deformation capacities of structural elements, seismic design of structure based on force analogy methods is not appropriate. In recent year, the basic approach of design codes have been changed from force-based approach to displacement-based. In this regard, a Direct Displacement-Based Design (DDBD) and a Performance-Based Plastic Design (PBPD) method are proposed. In this study, the efficiency of these two methods on seismic performance of structures is evaluated through a sample 12-story reinforced concrete moment frame. The building is designed separately based on the DDBD and the PBPD methods. Once again the structure is designed by the traditional force analogy method according to the FEMA P695 regulation. Different design method results in different structural elements. Seismic performance of these three structures is evaluated through nonlinear static and nonlinear dynamic analysis. The results show that the displacement-based design methods accommodate the intended performance objectives better than the traditional force analogy method.

Keywords: direct performance-based design, ductility demands, inelastic seismic performance, yield mechanism

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Authors: S. Aswath, Chinmaya Krishna Tilak, Amal Suresh, Ganesh Udupa

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There are technologies to control a humanoid robot in many ways. But the use of Electromyogram (EMG) electrodes has its own importance in setting up the control system. The EMG based control system helps to control robotic devices with more fidelity and precision. In this paper, development of an electromyogram based interface for human gesture recognition for the control of a humanoid robot is presented. To recognize control signs in the gestures, a single channel EMG sensor is positioned on the muscles of the human body. Instead of using a remote control unit, the humanoid robot is controlled by various gestures performed by the human. The EMG electrodes attached to the muscles generates an analog signal due to the effect of nerve impulses generated on moving muscles of the human being. The analog signals taken up from the muscles are supplied to a differential muscle sensor that processes the given signal to generate a signal suitable for the microcontroller to get the control over a humanoid robot. The signal from the differential muscle sensor is converted to a digital form using the ADC of the microcontroller and outputs its decision to the CM-530 humanoid robot controller through a Zigbee wireless interface. The output decision of the CM-530 processor is sent to a motor driver in order to control the servo motors in required direction for human like actions. This method for gaining control of a humanoid robot could be used for performing actions with more accuracy and ease. In addition, a study has been conducted to investigate the controllability and ease of use of the interface and the employed gestures.

Keywords: electromyogram, gesture, muscle sensor, humanoid robot, microcontroller, Zigbee

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Authors: M. Khaled Abduesslam, Mohammed Ali, Basher H. Alsdai, Muhammad Nizam Inayati

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This paper presents the voltage problem location classification using performance of Least Squares Support Vector Machine (LS-SVM) and Learning Vector Quantization (LVQ) in electrical power system for proper voltage problem location implemented by IEEE 39 bus New-England. The data was collected from the time domain simulation by using Power System Analysis Toolbox (PSAT). Outputs from simulation data such as voltage, phase angle, real power and reactive power were taken as input to estimate voltage stability at particular buses based on Power Transfer Stability Index (PTSI).The simulation data was carried out on the IEEE 39 bus test system by considering load bus increased on the system. To verify of the proposed LS-SVM its performance was compared to Learning Vector Quantization (LVQ). The results showed that LS-SVM is faster and better as compared to LVQ. The results also demonstrated that the LS-SVM was estimated by 0% misclassification whereas LVQ had 7.69% misclassification.

Keywords: IEEE 39 bus, least squares support vector machine, learning vector quantization, voltage collapse

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Authors: Alexey P. Antropov, Alexander V. Ragutkin, Nicolay A. Yashtulov

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The original controlled technology for power active nanocomposite membrane-electrode assembly engineering on the basis of porous silicon is presented. The functional nanocomposites were studied by electron microscopy and cyclic voltammetry methods. The application possibility of the obtained nanocomposites as high performance renewable energy sources for micro-power electronic devices is demonstrated.

Keywords: cyclic voltammetry, electron microscopy, nanotechnology, platinum-palladium nanocomposites, porous silicon, power activity, renewable energy sources

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Authors: Omid Heydarnia, Akbar Allahverdizadeh, Behnam Dadashzadeh, M. R. Sayyed Noorani

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Underactuated biped robots control is one of the interesting topics in robotics. The main difficulties are its highly nonlinear dynamics, open-loop instability, and discrete event at the end of the gait. One of the methods to control underactuated systems is the partial feedback linearization, but it is not robust against uncertainties and disturbances that restrict its performance to control biped walking and running. In this paper, fuzzy partial feedback linearization is presented to overcome its drawback. Numerical simulations verify the effectiveness of the proposed method to generate stable and robust biped walking and running gaits.

Keywords: underactuated system, biped robot, fuzzy control, partial feedback linearization

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Authors: Robel Habtemariam

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Globally, wind energy and photovoltaics (PV) solar energy are among the leading renewable energy sources (RES) in terms of installed capacity. In order to increase the contribution of RES to the power supply system, large scale energy integration is required, mainly due to wind energy and PV. In this paper, an investigation has been made on the electrical power supply systems of Taiwan and Greece in order to integrate high level of wind and photovoltaic (PV) to increase the penetration of renewable energy resources. Currently, both countries heavily depend on fossil fuels to meet the demand and to generate adequate electricity. Therefore, this study is carried out to look into the two cases power supply system by developing a methodology that includes major power units. To address the analysis, an approach for simulation of power systems is formulated and applied. The simulation is based on the non-dynamic analysis of the electrical system. This simulation results in calculating the energy contribution of different types of power units; namely the wind, PV, non-flexible and flexible power units. The calculation is done for three different scenarios (2020, 2030, & 2050), where the first two scenarios are based on national targets and scenario 2050 is a reflection of ambitious global targets. By 2030 in Taiwan, the input of the power units is evaluated as 4.3% (wind), 3.7% (PV), 65.2 (non-flexible), 25.3% (flexible), and 1.5% belongs to hydropower plants. In Greece, much higher renewable energy contribution is observed for the same scenario with 21.7% (wind), 14.3% (PV), 38.7% (non-flexible), 14.9% (flexible), and 10.3% (hydro). Moreover, it examines the ability of the power systems to deal with the variable nature of the wind and PV generation. For this reason, an investigation has also been done on the use of the combined wind power with pumped storage systems (WPS) to enable the system to exploit the curtailed wind energy & surplus PV and thus increase the wind and PV installed capacity and replace the peak supply by conventional power units. Results show that the feasibility of pumped storage can be justified in the high scenario (that is the scenario of 2050) of RES integration especially in the case of Greece.

Keywords: large scale energy integration, photovoltaics solar energy, pumped storage systems, renewable energy sources

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Authors: Jan Doutreloigne

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The main goal of this paper is to develop a switching amplifier with optimized power efficiency for analog signals with a very high crest factor such as audio or DSL signals. Theoretical calculations show that a switching amplifier architecture based on multi-level pulse width modulation outperforms all other types of linear or switching amplifiers in that respect. Simulations on a 2 W multi-level switching audio amplifier, designed in a 50 V 0.35 mm IC technology, confirm its superior performance in terms of power efficiency. A real silicon implementation of this audio amplifier design is currently underway to provide experimental validation.

Keywords: audio amplifier, multi-level switching amplifier, power efficiency, pulse width modulation, PWM, self-oscillating amplifier

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Authors: S. Muthuraja Soundrapandian, C.K. Subramaniam

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A micro Direct Methanol Fuel Cell (DMFC) of 1 cm2 active area with selective sensor materials to sense methanol for redox, has been developed. Among different Pt alloys, Pt-Sn/C was able to produce high current density and repeatability. Membrane Elecctrode Assembly (MEA) of anode catalyst Pt-Sn/C was prepared with nafion as active membrane and Pt black as cathode catalyst. The sensor’s maximum ability to detect the trace levels of methanol in ppm has been analyzed. A compact sensor set up has also been made and the characterization studies were carried out. The acceptable value of current density was derived by the cell and the results are able to fulfill the needs of DMFC technology for the practical applications.

Keywords: DMFC, sensor, MEA, Pt-Sn

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Authors: Chur Hee Lee, Jae in Lee, Minh Chau Diah, Jong Su Yoon, Seung Wan Kim

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This paper deals with Real Time Digital Simulator (RTDS) analysis about effects of transmission lines failure in power system equipped with Thyristor Controlled Series Capacitance (TCSC) in Korea. The TCSC is firstly applied in Korea to compensate real power in case of 765 kV line faults. Therefore, It is important to analyze with TCSC replica using RTDS. In this test, all systems in Korea, other than those near TCSC, were abbreviated to Thevenin equivalent. The replica was tested in the case of a line failure near the TCSC, a generator failure, and a 765-kV line failure. The effects of conventional operated STATCOM, SVC and TCSC were also analyzed. The test results will be used for the actual TCSC operational impact analysis.

Keywords: failure analysis, power system, RTDS, TCSC

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Authors: Zhiwen Yang, Jingyuan Li, Zhenkai Xie, Jian Ling, Jiguang Wang, Mengliang Li

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To reflect the effects of different emission control strategies, such as retrofitting after-treatment system and replacing with natural gas-fueled vehicles, on particle number (PN), particle mass (PM) and nitrogen oxides (NOx) emissions emitted by urban bus, a portable emission measurement system (PEMS) was employed herein to conduct real-world driving emission measurements on a diesel oxidation catalytic converter (DOC) and catalyzed diesel particulate filter (CDPF) retrofitting China IV diesel bus, a China IV diesel bus, and a China V natural gas bus. The results show that both tested diesel buses possess markedly advantages in NOx emission control when compared to the lean-burn natural gas bus equipped without any NOx after-treatment system. As to PN and PM, only the DOC+CDPF retrofitting diesel bus exhibits enormous benefits on emission control relate to the natural gas bus, especially the normal diesel bus. Meanwhile, the differences in PM and PN emissions between retrofitted and normal diesel buses generally increase with the increase in vehicle-specific power (VSP). Furthermore, the differences in PM emissions, especially those in the higher VSP ranges, are more significant than those in PN. In addition, the maximum peak PN particle size (32 nm) of the retrofitted diesel bus was significantly lower than that of the normal diesel bus (100 nm). These phenomena indicate that the CDPF retrofitting can effectively reduce diesel bus exhaust particle emissions, especially those with large particle sizes.

Keywords: CDPF, diesel, natural gas, real-world emissions

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Authors: Sopida Vacharasukpo, Sudarat Khwan-On

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This paper proposes a high step-up DC-DC converter topology for renewable energy system applications. The proposed converter employs only a single power switch instead of using several switches. Compared to the conventional DC-DC step-up converters the higher voltage gain with small output ripples can be achieved by using the proposed high step-up DC-DC converter topology. It can step up the low input voltage (20-50Vdc) generated from the photovoltaic modules to the high output voltage level approximately 600Vdc in order to supply the three-phase inverter fed the three-phase motor drive. In this paper, the operating principle of the proposed converter topology and its control strategy under the continuous conduction mode (CCM) are described. Finally, simulation results are shown to demonstrate the effectiveness of the proposed high step-up DC-DC converter with its control strategy to increase the voltage step-up conversion ratio.

Keywords: DC-DC converter, high step-up ratio, renewable energy, single switch

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Authors: Jasna Hudek-Knezevic, Igor Kardum, Nada Krapic, Martina Jurcic

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The aim of this study was to examine the effects of self- and partner reported attachment orientations on self-reported mate retention behaviors in romantic couples using the actor-partner interdependence model. The study was carried out on 187 heterosexual couples aged from 18 to 35 years, with an average relationship length of 4.5 years. Participants were asked to complete the revised scale of adult attachment and short form of mate retention inventory. Actor and partner effects of self- and partner reported anxious and avoidant attachment orientations on mate retention categories (direct guarding, intersexual negative inducements, positive inducements, public signals of possession and intrasexual negative inducements) and domains (cost-inflicting and benefit-provisioning), as well on overall mate retention were examined. Actor effects for women estimate whether their attachment orientations predict their own mate retention behaviors, whereas men’s actor effects estimate whether their attachment orientations predict their own mate retention behaviors. Women’s partner effects estimate whether their attachment orientations predict their partner’s mate retention behaviors, whereas men’s partner effects estimate whether their attachment orientations predict their partner’s mate retention behaviors. The use of two data sources, self- and partner reports, allow the control of the effects of common method variance when exploring actor and partner effects. Positive actor and partner effects of anxious attachment, as well as negative actor and partner effects of avoidant attachment on mate retention, were expected. In other words, it was expected that more anxiously attached individuals themselves, as well as their partners, will use mate retention behaviors more frequently. On the other hand, more avoidantly attached individuals themselves, as well as their partners, will use mate retention behaviors less frequently. These hypotheses were partially confirmed. The results showed that the strongest and most consistent effects across both data sources were men’s actor effects on the cost-inflicting mate retention domain, and especially on two mate retention categories, direct guarding, and intersexual negative inducements. Additionally, a consistent positive partner effect of men’s anxious attachment orientations on direct guarding was also obtained. Avoidant attachment orientation exerted few and inconsistent actor and partner effects on mate retention domains and categories. The results are explained by theoretical propositions addressing the effects of attachment orientations on an interpersonal romantic relationship in early adulthood.

Keywords: actor and partner effects, attachment orientations, dyadic analysis, mate retention behavior

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Authors: Ivan Orozco

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Introduction: Forced contraception constitutes part of an effort to control the life and reproductive capacity of women through public health institutions. This phenomenon has affected many Mexican women historically and still persists nowadays. The notion of reproductive governmentality refers to the mechanisms through which different historical configurations of social actors (state institutions, churches, donor agents, NGOs, etc.) use legislative controls, economic incentives, moral mandates, direct coercion, and ethical incitements, to produce, monitor and control reproductive behaviors and practices. This research focuses on the use of these mechanisms by the Mexican State to control women's contraceptive practices in a public hospital. Method: An Institutional Ethnography was carried out, with the objective of knowing women's experiences from their own perspective, as they occur in their daily lives, but at the same time, discovering the structural elements that shape the discourses that promote women's contraception, even against their will. The fieldwork consisted in an observation of the dynamics between different participants within a public hospital and the conduction of interviews with the medical and nursing staff in charge of family planning services, as well as women attending the family planning office. Results: Public health institutions in Mexico are state tools to control and regulate reproduction. There are several strategies that are used for this purpose, for example, health personnel provide insufficient or misleading information to ensure that women agree to use contraceptives; health institutions provide economic incentives to the members of the health staff who reach certain goals in terms of contraceptive placement; young women are forced to go to the family planning service, regardless of the reason they went to the clinic; health campaigns are carried out, consisting of the application of contraceptives outside the health facilities, directly in the communities of people who visit the hospital less frequently. All these mechanisms seek for women to use contraceptives, from the women’s perspective; however, the reception of these discourses is ambiguous. While, for some women, the strategies become coercive mechanisms to use contraceptives against their will, for others, they represent an opportunity to take control over their reproductive lives. Conclusion: Since 1974, the Mexican government has implemented campaigns for the promotion of family planning methods as a means to control population growth. Although it is established in several legislations that the counselling must be carried out with a gender and human rights perspective, always respecting the autonomy of people, these research testify that health personnel uses different strategies to force some women to use contraceptive methods, thereby violating their reproductive rights.

Keywords: feminist research, forced contraception, institutional ethnography, reproductive. governmentality

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Authors: Marwa Ahmed Abd El Hamied

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In this paper In this paper, a new technique based on Artificial Immunity System (AIS) technique has been developed to track Maximum Power Point (MPP). AIS system is implemented in a photovoltaic system that is subjected to variable temperature and insulation condition. The proposed novel is simulated using Mat Lab program. The results of simulation have been compared to those who are generated from Observation Controller. The proposed model shows promising results as it provide better accuracy comparing to classical model.

Keywords: component, artificial immunity technique, solar energy, perturbation and observation, power based methods

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Authors: Zdzislaw Kaminski, Zbigniew Czyz

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The paper discusses the results of the research into a wind turbine with a vertical axis of rotation which was performed with the open return wind tunnel, Gunt HM 170, at the laboratory of the Department of Thermodynamics, Fluid Mechanics and Propulsion Aviation Systems of Lublin University of Technology. Wind tunnel experiments are a necessary step to construct any new type of wind turbine, to validate design assumptions and numerical results. This research focused on the rotor with the blades capable of modifying their working surfaces, i.e. absorbing wind kinetic energy. The operation of this rotor is based on adjusting angular aperture α of the top and bottom parts of the blades mounted on an axis. If this angle α increases, the working surface which absorbs wind kinetic energy also increases. The study was performed on scaled and geometrically similar models with the criteria of similarity relevant for the type of research preserved. The rotors with varied angular apertures of their blades were printed for the research with a powder 3D printer, ZPrinter® 450. This paper presents the research results for the selected flow speed of 6.5 m/s for the three angular apertures of the rotor blades, i.e. 30°, 60°, 90° at varied speeds. The test stand enables the turbine rotor to be braked to achieve the required speed and airflow speed and torque to be recorded. Accordingly, the torque and power as a function of airflow were plotted. The rotor with its adjustable blades enables turbine power to be adjusted within a wide range of wind speeds. A variable angular aperture of blade working surfaces α in a wind turbine enables us to control the speed of the turbine and consequently its output power. Reducing the angular aperture of working surfaces results in reduced speed, and if a special current generator applied, electrical output power is reduced, too. Speed adjusted by changing angle α enables the maximum load acting on rotor blades to be controlled. The solution under study is a kind of safety against a damage of a turbine due to possible high wind speed.

Keywords: drive torque, renewable energy, power, wind turbine, wind tunnel

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Authors: Shukri Dughman, Anthony Rossiter

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This paper builds on earlier work which demonstrated that Model Predictive Control (MPC) may give a poor choice of default feed forward compensator. By first demonstrating the impact of future information of target changes on the performance, this paper proposes a pragmatic method for identifying the amount of future information on the target that can be utilised effectively in both finite and infinite horizon algorithms. Numerical illustrations in MATLAB give evidence of the efficacy of the proposal.

Keywords: model predictive control, tracking control, advance knowledge, feed forward

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Authors: Philipp Wenger, Michael Beltle, Stefan Tenbohlen, Uwe Riechert

Abstract:

The integration of renewable energy introduces new challenges to the transmission grid, as the power generation is located far from load centers. The associated necessary long-range power transmission increases the demand for high voltage direct current (HVDC) transmission lines and DC distribution grids. HVDC gas-insulated switchgears (GIS) are considered being a key technology, due to the combination of the DC technology and the long operation experiences of AC-GIS. To ensure long-term reliability of such systems, insulation defects must be detected in an early stage. Operational experience with AC systems has proven evidence, that most failures, which can be attributed to breakdowns of the insulation system, can be detected and identified via partial discharge (PD) measurements beforehand. In AC systems the identification of defects relies on the phase resolved partial discharge pattern (PRPD). Since there is no phase information within DC systems this method cannot be transferred to DC PD diagnostic. Furthermore, the behaviour of e.g. free-moving particles differs significantly at DC: Under the influence of a constant direct electric field, charge carriers can accumulate on particles’ surfaces. As a result, a particle can lift-off, oscillate between the inner conductor and the enclosure or rapidly bounces at just one electrode, which is known as firefly motion. Depending on the motion and the relative position of the particle to the electrodes, broadband electromagnetic PD pulses are emitted, which can be recorded by ultra-high frequency (UHF) measuring methods. PDs are often accompanied by light emissions at the particle’s tip which enables optical detection. This contribution investigates PD characteristics of free moving metallic particles in a commercially available 300 kV SF6-insulated HVDC-GIS. The influences of various defect parameters on the particle motion and the PD characteristic are evaluated experimentally. Several particle geometries, such as cylinder, lamella, spiral and sphere with different length, diameter and weight are determined. The applied DC voltage is increased stepwise from inception voltage up to UDC = ± 400 kV. Different physical detection methods are used simultaneously in a time-synchronized setup. Firstly, the electromagnetic waves emitted by the particle are recorded by an UHF measuring system. Secondly, a photomultiplier tube (PMT) detects light emission with a wavelength in the range of λ = 185…870 nm. Thirdly, a high-speed camera (HSC) tracks the particle’s motion trajectory with high accuracy. Furthermore, an electrically insulated electrode is attached to the grounded enclosure and connected to a current shunt in order to detect low frequency ion currents: The shunt measuring system’s sensitivity is in the range of 10 nA at a measuring bandwidth of bw = DC…1 MHz. Currents of charge carriers, which are generated at the particle’s tip migrate through the gas gap to the electrode and can be recorded by the current shunt. All recorded PD signals are analyzed in order to identify characteristic properties of different particles. This includes e.g. repetition rates and amplitudes of successive pulses, characteristic frequency ranges and detected signal energy of single PD pulses. Concluding, an advanced understanding of underlying physical phenomena particle motion in direct electric field can be derived.

Keywords: current shunt, free moving particles, high-speed imaging, HVDC-GIS, UHF

Procedia PDF Downloads 145

Authors: Wiji Wijaya

Abstract:

The aim of this research is to examine the effect of internal control weaknesses and audit opinion on the state’s loss findings of audit compliance to the regulation in public sector. The samples of this research consisted of 175 local government financial statements in the area of Central Java Province at 2009 until 2013. Area sampling design was used to select the financial statements. This study using quantitative descriptive statistical analysis and regression was run for data analysis and hypothesis examination. Result of this study indicated that internal control weaknesses and audit opinion contributes a positive influence which is significant to the state’s loss findings of audit compliance to the regulation. The internal control weaknesses that affect the state's loss finding are weakness control system of accounting and reporting with the value of the critical ratio 0.010 p 2.613 ; weakness budget execution control system with critical ratio value of 3.421 p 0.001 and weaknesses internal control structure with critical ratio value of 2.246 p 0.026 . While the audit opinion with a critical ratio value of 4.401 p 0.000. The implications of this research so that policy makers at the local government should give more attention to the implementation and improvement of internal control system.

Keywords: audit compliance findings, state’s loss, audit opinion, internal control, local government

Procedia PDF Downloads 363

Authors: Radim Farana, Bogdan Walek, Michal Janosek, Jaroslav Zacek

Abstract:

This paper presents the advantages of fuzzy control use in technological processes control. The paper presents a real application of the Linguistic Fuzzy-Logic Control, developed at the University of Ostrava for the control of physical models in the Intelligent Systems Laboratory. The paper presents an example of a sensitive non-linear model, such as a magnetic levitation model and obtained results which show how modern information technologies can help to solve actual technical problems. A special method based on the LFLC controller with partial components is presented in this paper followed by the method of automatic context change, which is very helpful to achieve more accurate control results. The main advantage of the used system is its robustness in changing conditions demonstrated by comparing with conventional PID controller. This technology and real models are also used as a background for problem-oriented teaching, realized at the department for master students and their collaborative as well as individual final projects.

Keywords: control, fuzzy logic, sensitive system, technological proves

Procedia PDF Downloads 452