Impact of intergrating teebus hydro power on the unbalanced distribution MV network

Small hydro power sources have been identified as one of the renewable energy technologies that the South African government is focusing on in order to generate more electricity from renewable/independent resources. Due to the low carbon output of most renewable energy technologies and the carbon intensive power generation technologies that are currently being used in South Africa e.g. Hydro, coal, gas, and etc. further pressure is increasing to incorporate cleaner forms of generation. In 2002 a study focusing on the hydropower potential was compiled providing an assessment according to conventional and unconventional possibilities for all the provinces. Nowadays, the power electricity demand is growing fast and one of the main tasks for power engineers is to generate electricity from renewable energy sources to overcome this increase in the energy consumption and at the same time reduce environmental impact of power generation. Eskom Distribution Eastern Cape Operating Unit (ECOU) was requested to investigate the feasibility of connecting a small hydro power scheme located in the Teebus area in the Eastern Cape. The Eastern Cape in particular, was identified as potentially the most productive area for small hydroelectric development in South Africa for both the grid connected and off grid applications. These network conditions are in contrast to the South African electricity network where long radial feeders with low X/R ratios and high resistance, spanning large geographic areas, give rise to low voltages on the network. Practical simulation networks have been used to test the conditions set out in the South African Grid Code/NERSA standard and to test the impact of connecting small hydro generation onto the unbalanced distribution network. These networks are representative of various real case scenarios of the South African distribution network. Most of the findings from the simulations were consistent with what was expected when comparing with other literatures. From the simulation results it was seen that the performance of the variable speed generators were superior to that of the fixed speed generators during transient conditions. It was also seen that the weakness of the network had a negative effect on the stability of the system. It is also noted that the stability studies are a necessity when connecting the generators to a network and that each case should be reviewed individually. The fundamental cause of voltage instability is identified as incapability of combined distribution and generation system to meet excessive load demand in either real power or reactive power form

International Conference on Energy

UBT Annual International Conference is the 11th international interdisciplinary peer reviewed conference which publishes works of the scientists as well as practitioners in the area where UBT is active in Education, Research and Development. The UBT aims to implement an integrated strategy to establish itself as an internationally competitive, research-intensive university, committed to the transfer of knowledge and the provision of a world-class education to the most talented students from all background. The main perspective of the conference is to connect the scientists and practitioners from different disciplines in the same place and make them be aware of the recent advancements in different research fields, and provide them with a unique forum to share their experiences. It is also the place to support the new academic staff for doing research and publish their work in international standard level. This conference consists of sub conferences in different fields like: Art and Digital Media Agriculture, Food Science and Technology Architecture and Spatial Planning Civil Engineering, Infrastructure and Environment Computer Science and Communication Engineering Dental Sciences Education and Development Energy Efficiency Engineering Integrated Design Information Systems and Security Journalism, Media and Communication Law Language and Culture Management, Business and Economics Modern Music, Digital Production and Management Medicine and Nursing Mechatronics, System Engineering and Robotics Pharmaceutical and Natural Sciences Political Science Psychology Sport, Health and Society Security Studies This conference is the major scientific event of the UBT. It is organizing annually and always in cooperation with the partner universities from the region and Europe. We have to thank all Authors, partners, sponsors and also the conference organizing team making this event a real international scientific event. Edmond Hajrizi, President of UBT UBT – Higher Education Institutio

Reliability Evaluation of Common-Cause Failures and Other Interdependencies in Large Reconfigurable Networks

This work covers the impact of Interdependencies and CCFs in large repairable networks with possibility of "re-configuration" after a fault and the consequent disconnection of the faulted equipment. Typical networks with these characteristics are the Utilities, e.g. Power Transmission and Distribution Systems, Telecommunication Systems, Gas and Water Utilities, Wi Fi networks. The main issues of the research are: (a) Identification of the specific interdependencies and CCFs in large repairable networks, and (b)Evaluation of their impact on the reliability parameters (load nodes availability, etc.). The research has identified (1) the system and equipment failure modes that are relevant to interdependencies and CCF, and their subsequent effects, and (2) The hidden interdependencies and CCFs relevant to control, supervision and protection systems, and to the automatic change-over systems, that have no impact in normal operation, but that can cause relevant out-of-service when the above automatic systems are called to operate under and after fault conditions. Additionally methods were introduced to include interdependencies and CCFs in the reliability and availability models. The results of the research include a new generalized approach to model the repairable networks for reliability analysis, including Interdependencies/CCFs as a main contributor. The method covers Generalized models for Nodes, Branches and Load nodes; Interdependencies and CCFs on Networks / Components; System Interdependencies/CCFs; Functional Interdependencies/CCFs; Simultaneous and non-simultaneous Interdependencies/CCFs. As an example detailed Interdependency/CCFs analysis and generalized model of an important network structure (a "RING" with load nodes) has been analyzed in detail

Study of superconducting fault current limiters in power systems

Power systems have increased both in scale and complexity as a result of rapid growth in the demand for power. The most common causes of failures in power systems are short-circuit faults. Short- circuit currents can grow thousands of times larger than normal system operating currents, i.e., within milliseconds. This places enormous thermal and mechanical stress on existing transmission infrastructure and may even cause blackouts. With the expansion and modernisation of power systems, fault current levels have also increased. The contributing factors include: the installation of new transmission facilities, transformers and generators, the upgrading of existing generators, and the integration of renewable energy sources. Conventional protection devices are unable to handle high fault current levels. Therefore a novel approach is required to limit the fault current level and to improve the resilience and reliability of power systems. The superconducting fault current limiter (SFCL) is one of the most significant and useful applications for high-temperature superconductors. It has many unique features which limit fault currents in power systems. Using the electrical characteristics of superconductors for current limitation is not a new idea. SFCL was first proposed in 1966 and has since been further developed. However, there is still much research needed on the SFCL device itself and its coordination with the traditional power grid. This thesis provides comprehensive and in-depth research on SFCLs and there are four new findings in this work. Firstly, we use four-probe methods to identify the best hierarchical structure for the 2G HTS YBCO tapes used for SFCL device in order to improve the fault current limiting effect. Three commercially available YBCO tapes are compared and the characteristics of one of the tapes have never been previously published. The work forms the foundation for the proper selection of YBCO tapes for SFCL devices, to support varying development and operational engineering requirements. Secondly, the study of SFCL integrated with a real AC power distribution network in Germany is accomplished using Finite Element Modeling (FEM) on Matlab Simulink. It provides the complete research procedures of SFCL integrated with a grid network and the underlying impact of this integration is thoroughly analyzed. The real data and sophisticated models employed here assure the simulation results are reliable and instructive for practical operation. Thirdly, we use PSCAD to simulate the SFCL installed in a Direct Current (DC) grid, and the SFCL has proved to be effective in preventing commutation failure in DC grid. Prior research done on the influence of SFCL on commutation failure has shown that it can mitigate commutation failure to some extent, but here we demonstrate R-SFCLs with correct resistance values can entirely solve the problem of commutation failures. It also shows that the SFCL has unsurpassed advantages compared to traditional mitigation methods. Fourthly, the coordination of SFCL with the Incremental Power Frequency Relay (IPFR) are studied by using PSCAD. The influence of SFCLs on grid protection is a critical area for SFCL engineering applications. The work examines the influences of R-SFCLs on IPFR of transmission lines, and proposes corresponding compensation methods. The theoretical analysis is innovative, and valuable for engineering applications

34th Midwest Symposium on Circuits and Systems-Final Program

Organized by the Naval Postgraduate School Monterey California. Cosponsored by the IEEE Circuits and Systems Society. Symposium Organizing Committee: General Chairman-Sherif Michael, Technical Program-Roberto Cristi, Publications-Michael Soderstrand, Special Sessions- Charles W. Therrien, Publicity: Jeffrey Burl, Finance: Ralph Hippenstiel, and Local Arrangements: Barbara Cristi

Advances and Technologies in High Voltage Power Systems Operation, Control, Protection and Security

The electrical demands in several countries around the world are increasing due to the huge energy requirements of prosperous economies and the human activities of modern life. In order to economically transfer electrical powers from the generation side to the demand side, these powers need to be transferred at high-voltage levels through suitable transmission systems and power substations. To this end, high-voltage transmission systems and power substations are in demand. Actually, they are at the heart of interconnected power systems, in which any faults might lead to unsuitable consequences, abnormal operation situations, security issues, and even power cuts and blackouts. In order to cope with the ever-increasing operation and control complexity and security in interconnected high-voltage power systems, new architectures, concepts, algorithms, and procedures are essential. This book aims to encourage researchers to address the technical issues and research gaps in high-voltage transmission systems and power substations in modern energy systems

Investigation into maximizing component availability for superconducting cables in turbo-electric distributed propulsion aircraft

The commercial aviation industry is growing at a substantial rate, with demand doubling every 15 years and this trend is set to continue well into the 21st Century. At the same time regulatory pressures are being exerted on the industry as governments around the world seek to reduce their greenhouse gas emissions in an effort to contain global temperature rise to 2°C . Combined with existing infrastructure challenges, these issues are forcing air-framers to develop new, novel designs that support sustainable approaches to future aviation to meet environmental, social and economic demands. The pathway to decarbonisation of aviation will involve a combination of fuel, technology and operational measures. Many of the proposed technologies, such as electrical propulsion, are inherently disruptive and require changes to supply-chains,ground operations, maintenance standards and procedures, and pilot training. Such disruption is unavoidable given the scale of the challenge of electrical propulsion: a typical widebody jet engine for passenger aircraft can output over 22 MW fully loaded; an equivalent electrical system must be able to generate, distribute, and produce same amount of thrust with equal or greater reliability than the existing drivetrain that has been perfected over the course of the last century. Turbo-electric Distributed Propulsion (TeDP) is an approach for the electrification of propulsion systems on aircraft that aims to do this. Instead of large turbofan engines used to generate thrust, power in the engines is converted to electricity using electrical generators, and then distributed electrically through a network to propulsion motors placed in aerodynamically advantageous locations, significant fuel savings and performance benefits may be realised. Electrification of the propulsion system comes with large weight penalties. It is critical that the weight of the electrical power system does not mitigate the benefits of electrification. Superconducting electrical machines have been proposed as a route to lightweighting the electrical power system due to their promising high power densities compared to conventional electrical machines. It is proposed that the rest of the electrical power system be superconducting as far as technically possible to minimise heat sinks within the system. Integration of superconducting materials into the most safety critical aspects of commercial aviation raises multiple research questions regarding the design of resilient systems and how appropriate electrical protection strategies can be designed given the strict electric, magnetic, and thermal operating requirements that these components have. All electrical systems experience faults. This Thesis investigates how these faults manifest within a compact, power-electronically interfaced, superconducting network. The research presented in this thesis captures electrical protection requirements through modelling, simulation, and experimentation to develop requirements for TeDP feeder cables. By building on these requirements this thesis will then show how cable design can be optimised to withstand faults and present a control method which enables maximising throughput of cables during temperature rise events. This knowledge aims to improve availability, in terms of reducing the amount of superconducting network de-rating required, and power provision of superconducting feeder cables during adverse conditions encountered by superconducting TeDP aircraft.The commercial aviation industry is growing at a substantial rate, with demand doubling every 15 years and this trend is set to continue well into the 21st Century. At the same time regulatory pressures are being exerted on the industry as governments around the world seek to reduce their greenhouse gas emissions in an effort to contain global temperature rise to 2°C . Combined with existing infrastructure challenges, these issues are forcing air-framers to develop new, novel designs that support sustainable approaches to future aviation to meet environmental, social and economic demands. The pathway to decarbonisation of aviation will involve a combination of fuel, technology and operational measures. Many of the proposed technologies, such as electrical propulsion, are inherently disruptive and require changes to supply-chains,ground operations, maintenance standards and procedures, and pilot training. Such disruption is unavoidable given the scale of the challenge of electrical propulsion: a typical widebody jet engine for passenger aircraft can output over 22 MW fully loaded; an equivalent electrical system must be able to generate, distribute, and produce same amount of thrust with equal or greater reliability than the existing drivetrain that has been perfected over the course of the last century. Turbo-electric Distributed Propulsion (TeDP) is an approach for the electrification of propulsion systems on aircraft that aims to do this. Instead of large turbofan engines used to generate thrust, power in the engines is converted to electricity using electrical generators, and then distributed electrically through a network to propulsion motors placed in aerodynamically advantageous locations, significant fuel savings and performance benefits may be realised. Electrification of the propulsion system comes with large weight penalties. It is critical that the weight of the electrical power system does not mitigate the benefits of electrification. Superconducting electrical machines have been proposed as a route to lightweighting the electrical power system due to their promising high power densities compared to conventional electrical machines. It is proposed that the rest of the electrical power system be superconducting as far as technically possible to minimise heat sinks within the system. Integration of superconducting materials into the most safety critical aspects of commercial aviation raises multiple research questions regarding the design of resilient systems and how appropriate electrical protection strategies can be designed given the strict electric, magnetic, and thermal operating requirements that these components have. All electrical systems experience faults. This Thesis investigates how these faults manifest within a compact, power-electronically interfaced, superconducting network. The research presented in this thesis captures electrical protection requirements through modelling, simulation, and experimentation to develop requirements for TeDP feeder cables. By building on these requirements this thesis will then show how cable design can be optimised to withstand faults and present a control method which enables maximising throughput of cables during temperature rise events. This knowledge aims to improve availability, in terms of reducing the amount of superconducting network de-rating required, and power provision of superconducting feeder cables during adverse conditions encountered by superconducting TeDP aircraft

Industrial Applications: New Solutions for the New Era

This book reprints articles from the Special Issue "Industrial Applications: New Solutions for the New Age" published online in the open-access journal Machines (ISSN 2075-1702). This book consists of twelve published articles. This special edition belongs to the "Mechatronic and Intelligent Machines" section

Data Challenges and Data Analytics Solutions for Power Systems

L'abstract è presente nell'allegato / the abstract is in the attachmen