Dissertations / Theses on the topic 'Mine power systems'

The continuing trend toward larger longwall mining systems has resulted in the utilization of higher system voltages. The increase in system voltage levels has caused the industry to face complexities not experienced with the lower-voltage systems. One such complexity arises from the larger system capacitance that results from the outby configuration commonly used on 4,160-V longwall power systems. Simulations show that during a line-to-ground fault, the larger system capacitance can cause a situation where the ground current sensed by the ground-fault relays in unfaulted circuits is greater than the mandated ground-fault relay pick-up setting. Simulations show that ground-fault relaying selectivity is potentially lost as a result of this situation. Two alternatives were identified which could improve ground-fault relaying selectivity. They are: the application of a directional relaying scheme and increasing the ground-fault relay pick-up setting. It was determined that directional relays have an application to high-voltage longwall power systems as the ground current sensed by the relay in the unfaulted circuits is out of phase with the ground-fault current sensed by the relay in the faulted circuit. Furthermore, it was determined that raising the ground-fault relay pick-up setting by a factor of eight would also improve ground-fault relaying selectivity. A safety analysis considering the potential for electrocution and the power dissipated by the maximum fault resistance showed that increasing the pick-up setting by a factor of eight would have no detriment to safety. Therefore, either method would improve ground-fault relaying selectivity on high-voltage longwall mining systems, yet because of the escalating size of longwall systems, a directional relaying scheme is a longer term solution.
Master of Science

The great innovations of the last century have ushered continuous progress in many areas of technology, especially in the form of miniaturization of electronic circuits. This progress shows a trend towards consistent decreases in power requirements due to miniaturization. According to the ITRS and industry leaders, such as Intel, the challenge of managing and providing power efficiency still persist as scaling down of devices continues. A variety of power sources can be used in order to provide power to low power applications. Few of these sources have favorable characteristics and can be designed to deliver maximum power such as the novel mini notched turbine used as a source in this work. The MiNT is a novel device that can be used as a feasible energy source when integrated into a system and evaluated for power delivery as investigated in this work. As part of this system, a maximum power point tracking system provides an applicable solution for capturing enhanced power delivery for an energy harvesting system. However, power efficiency and physical size are adversely affected by the characteristics and environment of many energy harvesting systems and must also be addressed. To address these issues, an analysis of mini notched turbine, a RF rectenna, and an enhanced maximum power point tracking system is presented and verified using simulations and measurements. Furthermore, mini notched energy harvesting system, RF rectenna energy harvesting system, and enhanced maximum power point tracking system are developed and experimental data analyzed. The enhanced maximum power point tracking system uses a resistor emulation technique and particle swarm optimization (PSO) to improve the power efficiency and reduce the physical size. This new innovative design improves the efficiency of optimized power management circuitry up to 7% compared to conventional power management circuits over a wide range of input power and range of emulated resistances, allowing more power to be harvested from small energy harvesting sources and delivering it to the load such as smart sensors. In addition, this is the first IC design to be implemented and tested for the patented mini notched turbine (MiNT) energy harvesting device. Another advantage of the enhanced power management system designed in this work is that the proposed approach can be utilized for extremely small energy sources and because of that the proposed work is valid for low emulated resistances. and systems with low load resistance Overall, through the successful completion of this work, various energy harvesting systems can have the ability to provide enhanced power management as the IC industry continues to progress toward miniaturization of devices and systems.

The design, construction and testing of a reverse-osmosis (PV-RO) desalination system for fresh water shortage area is presented. The system operates from salt water or brackish water and can be embedded in a renewable energy power supply system, since many fresh shortage areas are remote and isolated. Special attention is given to the energy efficiency of small-scale reverse osmosis desalination systems. Limitations of conventional control strategy using toggle control are presented. Based on this, an objective of creating a small-scale reverse osmosis desalination system was set out. Initially, the background information is presented. This includes the natural resources crisis and main desalination technologies and the viability of the integration with renewable energy source. A reverse osmosis (RO) desalination system was assembled and set up at the Curtin University of Technology, Perth, Western Australia Supervisor Control And Data Acquisition (SCADA) system was built using a Human Machine Interface software and a programmable logic controller (PLC). Instrumentation that included signal conditioners was made in analysis of the system characteristics. Initial testing of the system was conducted after the system design and configuration was accomplished. Testing results were used as a guideline for the development of the whole system.
Modelling and simulation of the system components in MATLABSimulink is presented, together with a discussion of the control systems modelling and design procedure, in which the aim was to improve the efficiency of the reverse osmosis system. Simulations show the designed reverse osmosis system with Proportional Integral and Derivative (PID) controller has better performance than other controllers. This consequently leads to a lower overall cost of the water, as well as reducing full maintenance cost of the electric drives in the reverse osmosis unit. Additionally, the configuration of the remote control system through General Package Radio System (GPRS) network is depicted. After the PID control algorithm was programmed into the Programmable Logic Controller (PLC), system experiments were carried out in short durations and long durations. System performance was monitored and experimental results prove that the new control strategy applied increase the water productivity and is able to improve the system efficiency up to 35%. Based on the data obtained from the simulations and experiments, Mundoo Island was chosen to be the location for a case study. The electric load profile of the island was derived from the Island Development Committee in Mundoo.
A water demand profile was created and modelled in Matlab to be the input of the reverse osmosis system. The electric load of the reverse osmosis system was generated from Matlab simulation. This result was entered in Hybrid Optimisation Model for Electric Renewables (HOMER) simulator. Having the designed RO unit as one of the electric loads, the entire remote area power supply (RAPS) system was tested in simulations which shows the energy cost is AUS$0.174 per kWh, lower than the Island Development Committee budget estimation of AUS$0.25 per kWh. The cost of the water treatment is very promising at AUS$0.77 per m3.

The aim of this study is to compare the cause of the, to date, three onlycommercial nuclear power plant accidents. These are very complex incidents,which have dire impact on society and the environment and therefore benefitfrom further investigation, if there lays a possibility of identifying factors thatcould prevent further accidents in the future. In order to investigate this theactions and decisions that lead up to each nuclear meltdown was identified andcompared.The investigation was based on a qualitative study on three cases of nuclearmeltdown accidents. They are based on text analysis of official reports anddocumentaries on the subject. The theoretical background for this study wasKajtazi’s (2011) work on Information Inadequacy. The study was limited to theevents leading up to the accidents and do not include activities afterwards.The study shows that each case had different underlying reasons. It alsoshows that we seem to have learned something from our previous mistakes, andacted on them accordingly. From the Fukushima Daiichi accident we canrecommend that organizations in charge should take early warnings seriouslyand act upon them as soon as they are presented.

Load, haul and dump machines (LHDs) are commonly used in underground mines around the world. The machines are used to transport fragmented ore after blasting in the ore body. The main propellant used is diesel which accounts for a large part of the diesel consumed in mines today. This master thesis is a pilot study for further work to be done by LTU and Atlas Copco in a project called SIMS or Sustainable Intelligent Mining Systems, where the aim is to physically demonstrate diesel free LHDs doing productive work in mines. The objective of the thesis was to assess if the integration of battery-powered LHD machines is plausible in today’s underground mines. The aims were to map the current state of the production and to perform risk and job analysis of the new technology in the current systems. A theoretical framework was constructed with focus on safety, risk, hazards and change in work content. Social acceptance was then researched to be able to analyze how the new technology is received. Data gathering was done through interviews, observations, a focus group and reviewing documents while visiting Atlas Copco and two underground mines in Sweden. Diesel and electric-powered LHDs were studied in the mines and battery-powered LHDs were studied at Atlas Copco. The results present the current state of diesel, electric and battery-powered LHDs. How the machines are used in the visited mines and the identified risks with the work is presented along with the mapping of the battery system being developed by Atlas Copco. New risks that the battery system will bring to the work environment were identified using energy and deviation analyzes. The change in work content was discussed using the information from the visits and identifying what tasks will change, disappear and be added with the new technology. A large part of the thesis was analyzing the results with support from the theoretical framework. The analysis showed that a switch from diesel to battery-power would improve the overall health and safety inside the mines. A switch does not change the skill needed to operate the machines but can increase the qualifications for the service personnel. The main obstacles, in terms of social acceptance, with implementing the battery systems in the current state are that the need for constant battery exchange would cause problems in the production, the prejudice that the batteries would increase the consequences of a fire and the initial cost of making the switch. Recommendations for Atlas Copco going forward in the SIMS project were made. They need to emphasizing the safety of the technology to the users, developing the battery exchange so it can be done closer to the stopes and involve the operators in the projects of SIMS to help them understand the benefits it will have on them directly.
Gruvlastmaskiner (LHD) används ofta i gruvor runt om i världen. Maskinerna används för transportera fragmenterade malm efter malmen sprängts. Det huvudsakliga drivmedlet som används är diesel, som står för en stor del av den diesel som förbrukas i gruvor idag. Detta examensarbete är en pilotstudie för ytterligare arbete som ska utföras av LTU och Atlas Copco i ett projekt som heter SIMS eller Sustainable Intelligent Mining Systems. Syftet är att fysiskt demonstrera dieselfria LHD-maskiner göra produktivt arbete i gruvor. Syftet med examensarbetet var att bedöma om integrationen av batteridrivna LHD-maskiner är möjligt i dagens underjordiska gruvor. Målet var att kartlägga den aktuella produktionssituationen och att utföra risk- och arbetsanalyser av den nya tekniken i nuvarande system. En teoretisk referensram konstruerades med fokus på säkerhet, risk och förändring i arbetsinnehåll. Social acceptans undersöktes sedan för att kunna analysera hur den nya tekniken tas emot. Datainsamlingen gjordes genom intervjuer, observationer, en fokusgrupp och granskning av dokument givna vid besök på Atlas Copco och två underjordiska gruvor i Sverige. Diesel- och el-drivna maskiner studerades i gruvorna och batteridrivna studerades hos Atlas Copco. Resultaten presenterar det nuvarande läget för diesel, elektriska och batteridrivna LHDmaskiner. Hur maskinerna används i de besökta gruvorna och de identifierade riskerna med arbetet presenteras tillsammans med kartläggningen av batterisystemet som utvecklas av Atlas Copco. Nya risker med batterisystemet identifierades med hjälp av energi- och avvikelsesanalyser. Ändringarna i arbetsinnehåll diskuterades med hjälp av informationen från besöken och klargör vilka uppgifter som ska förändras, försvinnas och läggas till med den nya tekniken. En stor del av arbetet var att analysera resultaten med stöd från den teoretiska referensramen. Analysen visade att bytet från diesel till batterier skulle förbättra hälsan och säkerheten i gruvorna. Teknologibytet förändrar inte den färdighet som krävs för att kunna manövrera maskinerna men kan öka kvalifikationerna för servicepersonalen. De viktigaste hindren när det gäller social acceptans med att implementera batterisystemen i det nuvarande tillståndet är att behovet av konstant batteribyte skulle orsaka problem i produktionen, fördomarna om att batterierna skulle öka konsekvenserna av en brand och de initiala kostnaderna att göra ett byte. Rekommendationer för Atlas Copco för fortsatt arbete i SIMS-projektet gjordes. De behöver klargöra säkerheten hos den nya teknik för användarna, utveckla batteribytet så att det kan göras närmare produktionen och involvera operatörerna i SIMS-projekten för att hjälpa dem att förstå de fördelar som det kommer att ha på dem direkt.

Fuel supply issues are a major concern in remote island communities and this is an engineering field that needs to be analyzed in detail for transition to sustainable energy systems. Power generation in remote communities such as the islands of the Maldives relies on power generation systems primarily dependent on diesel generators. As a consequence, power generation is easily disrupted by factors such as the delay in transportation of diesel or rises in fuel price, which limits shipment quantity. People living in remote communities experience power outages often, but find them just as disruptive as people who are connected to national power grids. The use of renewable energy sources could help to improve this situation, however, such systems require huge initial investments. Remote power systems often operate with the help of financial support from profit-making private agencies and government funding. Therefore, investing in such hybrid systems is uncommon. Current electrical power generation systems operating in remote communities adopt an open loop control system, where the power supplier generates power according to customer demand. In the event of generation constraints, the supplier has no choice but to limit the power supplied and this often results in power cuts. Most smart grids that are being established in developed grids adopt a closed loop feedback control system. The smart grids integrated with demand side management tools enable the power supplier to keep customers informed about their daily energy consumption. Electric utility companies use different demand response techniques to achieve peak energy demand reduction by eliciting behavior change. Their feedback information is commonly based on factors such as cost of energy, environmental concerns (carbon dioxide intensity) and the risk of black-outs due to peak loads. However, there is no information available on the significant link between the constraints in resources and the feedback to the customers. In resource-constrained power grids such as those in remote areas, there is a critical relationship between customer demand and the availability of power generation resources. This thesis develops a feedback control strategy that can be adopted by the electrical power suppliers to manage a resource-constrained remote electric power grid such that the most essential load requirements of the customers are always met. The control design introduces a new concept of demand response called participatory demand response (PDR). PDR technique involves cooperative behavior of the entire community to achieve quality of life objectives. It proposes the idea that if customers understand the level of constraint faced by the supplier, they will voluntarily participate in managing their loads, rather than just responding to a rise in the cost of energy. Implementation of the PDR design in a mini-grid consists of four main steps. First, the end-use loads have to be characterized using energy audits, and then they have to be classified further into three different levels of essentiality. Second, the utility records have to be obtained and the hourly variation factors for the appliances have to be calculated. Third, the reference demand curves have to be generated. Finally, the operator control system has to be designed and applied to train the utility operators. A PDR case study was conducted in the Maldives, on the island of Fenfushi. The results show that a significant reduction in energy use was achieved by implementing the PDR design on the island. The overall results from five different constraint scenarios practiced on the island showed that during medium constrained situations, load reductions varied between 4.5kW (5.8%) and 7.7kW (11.3%). A reduction of as much as 10.7kW (15%) was achieved from the community during a severely constrained situation.

This report is the result of a conducted Minor Field Study (MFS), to the greatestextent funded by the Swedish International Development Cooperation Agency(SIDA), in an attempt to design a system for evaluating smaller solar power systems indeveloping countries. The study was to the greater part conducted in Nairobi, Kenyain close collaboration with the University of Nairobi. The aim was to develop asystem that would use easily available components and keep the costs to a minimum,yet deliver adequate performance. The system would measure certain parameters of asolar power system and also relevant environmental data in order to evaluate theperformance of the system. Due to the specific competence of the collaboratinggroup at the University of Nairobi, a Kinetis Freescale K64-microcontroller with anARM-Cortex processor was selected as the core of the design. Components wereselected, schematics were drawn, a circuit board was designed and manufactured andsoftware was written. After 12 weeks a somewhat satisfying proof-of-concept wasreached at the end of the field study in Kenya. The project however proved howdifficult it is to go from first idea to a functional proof-of-concept during a limitedtimeframe, and also in an East-African country. The final proof-of-concept was testedat Mpala Research Centre in Kenya and despite containing some flaws proved that itwould indeed be possible to design a working system on the principles discussed inthis report. The system is open-source, so anyone may use and modify it.

Confronté à un contexte de stagnation globale de la consommation d'électricité mais avec un potentiel important de développement de nouveaux usages, ainsi qu'à l'apparition d'unités de production dispersée sur le territoire, le principal gestionnaire de réseau de distribution français a besoin d'expliciter ce que sont ses grands choix de structure et de règles d'exploitation, et de les comparer avec les distributeurs étrangers. Les principes de construction du réseau ont un impact sur la capacité à intégrer les nouvelles installations de consommation ou de production à moindre cout, et à assurer les exigences sociétales,notamment pour ce qui concerne la continuité de fourniture. Cette thèse permet de comparer ces choix techniques majeurs avec les pratiques rencontrées à l'étranger, pour situer le réseau français et ses spécificités dans un environnement technique international.Après avoir arrêté une perspective de développement des usages et des productions en France sur la base notamment des textes législatifs, l'architecture du réseau de distribution français est décrite. Les différences fonctionnelles de choix de structure dans le monde sont alors analysés, en soulignant les conséquences dans le dimensionnement par rapport au cas français. Puis l'équilibre entre niveaux de tension est questionné, ainsi que les effet des caractéristiques du territoire sur le réseau. Enfin, des choix techniques nouveaux sont proposés après analyse des points forts et des points faibles des variantes existant dans le monde
Faced to a context of a global lack of growth in electricity consumption, but with many potential development of new uses, added with the appearance of more and more dispersed generation, the main French distribution grid utility needs to question and compare its choicesconcerning grid structure and exploitation practices. Grid building principles have a greatimpact over its capacity to integrate at low cost consumption and production facilities, whilemeeting society needs, mainly continuity of supply. This work allows to compare thosetechnical choices between France and other countries, to determine where French utilitystands and what are its specific features in a worldwide technical environment.After setting a perspective about uses and production development, mainly on the basis of French legislation, the overall distribution grid architecture is described. Functional differences in structure choices in the world are then analysed, their consequences in thesizing of equipments is underlined. Then the equilibrium between voltage levels is questioned,as the effect of territorial features on the grid. Finally, new technical choices are proposed after advantages and drawbacks analysis of existing world grids

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No transcorrer de seu complexo devir histórico o ser humano se deparou com diversas problemáticas e perplexidades que dizem respeito a sua própria existência. Uma delas, talvez a mais paradoxal de todas, é a episteme de ser humano fundada na cisão corpo/mente. A educação física, como parte da educação escolar, historicamente teve como função, a partir dessa episteme dualista, o cuidado para com o corpo – res extensa. A partir dessa perspectiva a presente pesquisa teve como principal objetivo: Compreender de que forma nas diversas práxis de educação física se articulam a episteme fundada na cisão corpo/mente. A preocupação em se estabelecer tal pesquisa se deve ao fato de deduzirmos haver em tal episteme a origem de vários problemas da educação física. Reconhecemos nela também uma desumanização, sobretudo como realidade histórica da condição humana. Condição esta que tem e teve, nas práxis das várias ciências que as sustentaram e disseminaram sua humanidade, até certo ponto roubada. Deste modo nossa pesquisa se orientou sob o seguinte pressuposto: A episteme de cisão corpo/mente – construída historicamente – articula-se nas práxis de educação física através de jogos de poder/saber, regimes de verdade, símbolos culturais e imaginários sociais subjetivando e objetivando os sujeitos contribuindo assim para a manutenção e reprodução do sistema de produção econômica. Percebeu-se através da pesquisa a existência de técnicas, táticas e práxis que se estruturam e se perpetuam a partir desta episteme de cisão. Assim apresentamos: a mente como alvo no processo de ensino/aprendizagem; o condicionamento da mente, a imobilização e o controle do corpo no ambiente escolar; a episteme de cisão corpo/mente: o desporto e a biologização da educação física; a biologização humana e o homem máquina na educação física; bem como a (in)exclusão e a episteme de cisão corpo/mente. Tratou-se de uma pesquisa qualitativa que abordou o tema sob o viés de um estudo bibliográfico.
Salvador

M.Ing.
This thesis considers in detail the applicability to hydro power systems of the theories of steady and unsteady flow in pipelines. In doing so.it highlights some of the shortcomings of these theories. An attempt is made by way of experimentation on a high pressure pipeline, to model some of the conditions which could occur in a full size future hydro power system. These experiments provide some quantitative data about the performance of some typical hydro power components such as pipes, orifices and valves, under steady and unsteady conditions. A computer program is included which was used to provide theoretical data to compare with the experimental results. The program was found to be limited in its capacity to provide accurate simulation of the experimental pipeline, but this was thought to be due to the pipeline not correctly modelling a hydro power system. Conclusions presented in this thesis will be of assistance to designers of future hydro power systems and to researchers continuing this work.

碩士
銘傳大學
電子工程學系碩士班
98
Due to the fuel shortage and the policy of reducing carbon dioxide. This thesis presents the design of solar and wind hybrid power system in Ming Chuan University, in order to understand whether this system is suitable our campus for or not. We set up a wind and solar hybrid power system, winds device and thermometer in Ming Chuan University. We also write a labview program for recoding data and monitoring on time. We hope that through the long term monitoring and data collection can be used to to assess the effectiveness of hybrid power system in our campus is suitable or not.

碩士
國立臺北科技大學
車輛工程系
106
This research is to improve the old multi-functional mini loader and combine the power of the engines and motors so that the energy can achieve the best efficiency. In terms of power design, the unique power of the multi-functional mono loader: the engine, was upgraded to a hybrid power system based on the Belt-Starter Generator (BSG) system. The BSG system can switch to a hybrid power mode or a engine power mode when operating outdoors or in open space; it can switch to motor power mode when operating indoors or in a narrow space. The advantage is that the fuel economy of the hybrid power mode is higher than the engine mode, and the hybrid mode can increase the working time at the same fuel quantity, the motor mode can reduce air pollution in narrow spaces and more friendly to relief workers. In terms of size design, considering the size of existing large-scale excavation machine tools, we have designed the ability to pass through narrow doors. Its advantage is that it can work quickly in narrow spaces or alleys. This study has been tested and found that the new multi-functional mini loader can increase the working time by more than 30 minutes under the same fuel quantity, and can pass the small door of 770 mm wide and can span the short step of 140 mm. It can reach the expected goal of this study by spanning a 300 mm trench and climbing up to 30% of the slope. The new multi-functional mini loader have reached the expected goals of this study.

Reliable electricity supply remains a major problem in rural India nowadays. Renewable off-grid solutions have been applied in the last decades to increase power supply reliability but often failed to be feasible due to their high energy costs compared to the national grid. Grid Integrated Mini-grids with Storage (GIMS) can provide reliable power supply at an affordable price by combining mini-grids and national grid facilities. However, research on the techno-economic feasibility of these systems in the country is very limited and unavailable in the public sphere. This research project analysed three different aspects of the GIMS feasibility. First, the feasibility of the use of hybrid wind and solar Photovoltaic (PV) systems in GIMS was analysed by comparing the Levelised Cost of Electricity (LCOE) and Net Present Cost (NPC) of solar PV and hybrid PV/Wind GIMS systems. Second, the potential savings GIMS can offer due to the possibility of selling power to the grid were quantified by comparing the LCOE and NPC of the system with and without grid export. Lastly, the cost of reliability of the power supply was represented by the influence of the allowed percentage of capacity shortage on the total cost of the system. The analysis was carried out by means of the software HOMER and was based on three case studies in India. The results of this analysis showed that the use of hybrid systems could generate savings of up to 17% of the LCOE of the GIMS system in comparison to solar mini-grids. Moreover, power sales to the grid enabled LCOE savings up to 35% with respect to mini-grid without power sell-back possibility. In addition, the LCOE could be reduced in between 28% and 40% in all cases by enabling up to a 5% of capacity shortage in the system.
En tillförlitlig elförsörjning är ett stort problem på landsbygden i Indien. Elnätslösningar baserade på förnybara energikällor har undersökts under de senaste decennierna för att öka tillförlitligheten men har ofta misslyckats i genomförandefasen på grund av höga energikostnader jämfört med i det nationella nätet. Nätintegrerade mini-grids med energilagring (GIMS) kan ge tillförlitlig strömförsörjning till ett överkomligt pris genom att kombinera mini-grids och nationella elnätsanläggningar. Forskningen om den tekniskekonomiska genomförbarheten av dessa system i landet är emellertid mycket begränsad och otillgänglig inom den offentliga sfären. I den här studien analyseras tre olika aspekter av GIMS-genomförbarheten. För det första analyserades genomförbarheten av att använda hybrida vind- och solcellssystem i GIMS genom att jämföra ”Levelised Cost of Electricity” (LCOE) nivån och nuvärdeskostnaden (NPC) för solcellssystem (PV) och hybrid PV/Vind GIMS-system. För det andra kan de potentiella besparingar GIMS erbjuder, genom möjligheten att sälja elenergi till nätet, kvantifieras genom att jämföra LCOE och NPC i systemet med och utan ”nätexport”. Slutligen studeras kostnaden för tillförlitligheten hos strömförsörjningen i förhållande till accepterad kapacitetsbrist med avseende på systemets totala kostnad. Analysen har utförts med hjälp av mjukvaran HOMER och grundas på tre fallstudier i Indien. Resultaten av denna analys visar att användningen av hybridsystem skulle kunna generera besparingar på upp till 17% av LCOE i GIMS-systemet i jämförelse med enbart PV-baserade mini-grids. Försäljning av elenergi till nätet möjliggör LCOE-besparingar på upp till 35% med i förhållande till mini-grids utan möjlighet till export. Slutligen: LCOE kunde reduceras mellan 28% och 40% i samtliga fall genom att tillåta upp till 5% kapacitetsbrist i systemet.

D.Ing. (Electrical and Electronic Engineering)
The electricity shortage in South Africa has required the implementation of demand side management (DSM) projects. The DSM projects were implemented by installing energy monitoring and control systems to monitor certain mining aspects such as water pumping systems. Certain energy saving procedures and control systems followed by the mining industry are not sustainable and must be updated regularly in order to meet any changes in the water pumping system. In addition, the present water pumping, monitoring, and control system does not predict the energy consumption or the underground water dam levels. Hence, there is a need to introduce new monitoring system that could control and predict the energy consumption of the underground water pumping system and dam levels based on present and historical data. The work is undertaken to investigate the feasibility of using artificial intelligence in certain aspects of the mining industry. If successful, artificial intelligence systems could lead to improved safety and reduced electrical energy consumption, and decreased human error that could occur throughout the pump station monitoring and control process ...

The generation of compressed air comprises 20% of the total electricity usage in the mining industry, although compressed air is often seen as a free source of energy. There are however significant costs associated with generating compressed air and maintaining a compressed air system. There are several methods to optimise the electricity used to generate compressed air. The focus of this study is on one of these methods – the implementation of a dynamic air compressor selector. A Dynamic Compressor Selector (DCS) system was developed to fulfil this purpose. DCS is a system that combines demand- and supply-side management of a compressed air network. DCS calculates a pressure set point for compressors and schedules the compressors according to the demand from the end-users. End-users include shafts, plants, workshops and smelters. DCS takes all of the compressors and end-users into consideration while doing the calculations. This dissertation focuses on the DCS implementation process and on the problems encountered by previous authors while implementing the DCS technology. Additional problems were encountered while the DCS technology was implemented. DCS was however still successfully implemented. This study will expand the implementation procedure to ensure that the technology can be implemented successfully in the future. DCS was implemented at a platinum mine in South Africa where it was able to calculate pressure set points for the compressors. DCS was able to accurately match the supply of, and demand for compressed air closely, resulting in lower overall compressed air usage. DCS improved compressor scheduling and control, limiting compressor cycling. Improved compressor scheduling and control resulted in significant decreases in the electricity used to generate compressed air at the mine. A target average evening peak clip of 2.197 MW was simulated, set and achieved. Evening peak clip power savings in excess of an average of 3 MW were achieved.
MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

碩士
國立中山大學
電機工程學系研究所
96
The first topic of the thesis reveals a mini-invasive low-power measurement system for bladder pressure measurement. Not only can the mode of measurement be selected, the input range and amplification of instrumentation amplifier (IA) is also adjustable. The proposed system can measure the pressure in a bladder in a continuous mode. It also can monitor the pressure in a long-term mode with an automatic sleeping mechanism for power saving. The signal generated by the pressure sensor is sensed by an IA, which is then fed into the following ADC (analog-to-digital converter). The input range of the IA must be adjustable to keep the required linearity. The pressure range of the proposed system is found out to be 5 Psi with the maximum resolution of 1 cm-H2O, which covers the range of all of the known unusual bladder syndromes. The second topic is a self-disable sense technique for content addressable memory (CAM). The differential match-line sense circuit can be self-disabled to choke the charge current fed into the match line right after the comparison result is generated. Besides, the 13-T CAM cell provides the complete write, read, and comparison functions to refresh the data bit and verify its correctness before searching. The average energy consumption of the searching process is 1.872 fJ/bit/search according to thorough simulations.

Recent advancements in silicon technology have paved the way for the development of integrated transceivers operating well inside the mm-wave frequency range (30 - 300 GHz). This band offers opportunities for new applications such as remote sensing, short range radar, active imaging and multi-Gb/s radios. This thesis presents new ideas at the circuit and system level for a variety of such applications, up to 145 GHz and in both state-of-the-art nanoscale CMOS and SiGe BiCMOS technologies. After reviewing the theory of operation behind linear and power amplifiers, a purely digital, scalable solution for power amplification that takes advantage of the significant ft/fmax improvement in pFETs as a result of strain engineering in nanoscale CMOS is presented. The proposed Class-D power amplifier, features a stacked, cascode CMOS inverter output stage, which facilitates high voltage operation while employing only thin-oxide devices in a 45 nm SOI CMOS process. Next, a single-chip, 70-80 GHz wireless transceiver for last-mile point-to-point links is described. The transceiver was fabricated in a 130 nm SiGe BiCMOS technology and can operate at data rates in excess of 18 Gbps. The high bitrate is accomplished by taking advantage of the ample bandwidth available at the W-band frequency range, as well as by employing a direct QPSK modulator, which eliminates the need for separate upconversion and power amplification. Lastly, the system and circuit level implementation of a mm-wave precision distance and velocity sensor at 122 and 145 GHz is presented. Both systems feature a heterodyne architecture to mitigate the receiver 1/f noise, as well as self-test and calibration capabilities along with simple packaging techniques to reduce the overall system cost.