Optimised design of isolated industrial power systems and system harmonics

This work has focused on understanding the nature and impact of non-linear loads on isolated industrial power systems. The work was carried out over a period of 8 years on various industrial power systems: off-shore oil and gas facilities including an FPSO, a wellhead platform, gas production platforms, a mineral processing plant and an LNG plant. The observations regarding non-linear loads and electrical engineering work carried out on these facilities were incorporated into the report.A significant literature describing non-linear loads and system harmonics on industrial power systems was collected and reviewed. The literature was classified into five categories: industrial plants and system harmonics, non-linear loads as the source of current harmonics, practical issues with system harmonics, harmonic mitigation strategies and harmonic measurements.Off-shore oil and gas production facilities consist of a small compact power system. The power system incorporates either its own power generation or is supplied via subsea cable from a remote node. Voltage selection analysis and voltage drop calculation using commercially available power system analysis software are appropriate tools to analyse these systems. Non-linear loads comprise DC rectifiers, variable speed drives, UPS systems and thyristor controlled process heaters. All nonlinear loads produce characteristic and non-characteristic harmonics, while thyristor controlled process heaters generate inter-harmonics. Due to remote location, harmonic survey is not a common design practice. Harmonic current measurements during factory acceptance tests do not provide reliable information for accurate power system analysis.A typical mineral processing plant, located in a remote area includes its own power station. The power generation capacity of those systems is an order of magnitude higher than the power generation of a typical off-shore production facility. Those systems comprise large non-linear loads generating current and voltage interharmonics. Harmonic measurements and harmonic survey will provide a full picture of system harmonics on mineral processing plants which is the only practical way to determine system harmonics. Harmonic measurements on gearless mill drive at the factory are not possible as the GMD is assembled for the first time on site.LNG plants comprise large non-linear loads driving gas compressor, however those loads produce integer harmonics. Design by analysis process is an alternative to the current design process based on load lists. Harmonic measurements and harmonic survey provide a reliable method for determining power system harmonics in an industrial power system

Power system modelling analysis: An engineering internship at Fortescue Metals Group

To fulfil the requirements of the Bachelor of Engineering at Murdoch University, students are required to undertake either a research project or internship project. This final year thesis project was carried out during an internship placement at Fortescue Metals Group (“Fortescue”). The project involved the modelling and analysis of a new power system at one of Fortescue’s mine sites in the Pilbara region of Western Australia. Power systems are modelled for the purpose of analysing system safety, reliability and efficiency. The process that engineers take to ensure power systems have these qualities in the design phase is greatly simplified by modelling. The modelling is carried out using specialised power system analysis tools in order to simulate the steady-state and transient operating conditions that system components are likely to be subjected to. The power system modelling at Fortescue was carried out in the preferred modelling software, PowerFactory by DIgSILENT. The studies that were undertaken for analysis were Load Flow, Short-Circuit and Motor-Starting Studies, with an additional task of assessing the coordination of protective devices. The Load Flow study was carried out for the normal operation of the system, where the system is running at maximum demand. The Short-Circuit study scenarios included the maximum and minimum prospective fault currents during three-phase short-circuits and single-phase to ground short-circuits. The Motor-Starting studies were carried out on the maximum motor loads connected to each substation. The methodology and techniques used to conduct these studies are outlined in the report. The results indicated that the system components were adequately rated in order to safely and reliably supply power to the various loads. Equipment ratings were not exceeded in normal operation of the system, or throughout any of the short-circuit fault scenarios. The studies illustrated that motors could successfully start-up without damaging equipment due to inrush currents, and the protection settings were all adequately coordinated. The detailed analysis of these results is carried out throughout this internship report

Safety implications of the introduction of a specially tested assembly into the South African national standard for low-voltage assemblies.

Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2004.Low-voltage switchgear and controlgear assemblies with a rated short-circuit withstand strength above 10 kA, are required, by law, to conform to the South African standard, SANS 1473-1 (Low Voltage Switchgear and Controlgear Assemblies: Part 1: Typetested, partially type-tested and specially tested assemblies with rated short-circuit withstand strength above lOkA). Standard SANS 1473-1 stipulates three categories of assemblies i.e. type-tested, partially type-tested and specially tested assemblies. The specially tested assembly is unique to the South African market, while the other two categories are stipulated in standard SANS IEC 60439-1 (Low Voltage Switchgear and Controlgear Assemblies: Part 1: Type-tested and partially type-tested assemblies), which is internationally accepted in many countries as the applicable low-voltage assembly standard. Standard SANS 1473-1 specifies seven type-tests for certification as a type-tested assembly (TTA), but specifies, at most, three type-tests for certification as a specially tested assembly (STA). The underlying purpose of a technical standard is to provide for the safety of people and property, with the purpose of the research being twofold: 1. To investigate if the testing requirements specified for a specially tested assembly (STA), in accordance with standard SANS 1473-1, are correctly applied, and do not pose any safety risks. 2. To investigate any safety risks that stem from the fact that four type-tests are excluded for verification as a specially tested assembly (STA), as opposed to the seven type tests required for verification as a type-tested assembly (TTA). The document highlights the technical inadequacies of an assembly that is certified as a STA, in accordance with standard SANS 1473-1, and the potential safety risks associated with this type of assembly classification

Innovation in Energy Systems

It has been a little over a century since the inception of interconnected networks and little has changed in the way that they are operated. Demand-supply balance methods, protection schemes, business models for electric power companies, and future development considerations have remained the same until very recently. Distributed generators, storage devices, and electric vehicles have become widespread and disrupted century-old bulk generation - bulk transmission operation. Distribution networks are no longer passive networks and now contribute to power generation. Old billing and energy trading schemes cannot accommodate this change and need revision. Furthermore, bidirectional power flow is an unprecedented phenomenon in distribution networks and traditional protection schemes require a thorough fix for proper operation. This book aims to cover new technologies, methods, and approaches developed to meet the needs of this changing field

Sustainable Development (SD) Design of an Electrical System A Case Study of Asiaflex Products Sdn B lid

Sustainable development (SD) is a simple way of ensuring a better quality of life for everyone, now and for generation to conic. It refers to a perspective that considers all three aspects which are social, economic and the environmental. Designing an electrical system with sustainability refers to an approach that considers the use of renewable energy, energy efficiency, conservation and nlnmising usage of natural resources

Innovation in Energy Systems

It has been a little over a century since the inception of interconnected networks and little has changed in the way that they are operated. Demand-supply balance methods, protection schemes, business models for electric power companies, and future development considerations have remained the same until very recently. Distributed generators, storage devices, and electric vehicles have become widespread and disrupted century-old bulk generation - bulk transmission operation. Distribution networks are no longer passive networks and now contribute to power generation. Old billing and energy trading schemes cannot accommodate this change and need revision. Furthermore, bidirectional power flow is an unprecedented phenomenon in distribution networks and traditional protection schemes require a thorough fix for proper operation. This book aims to cover new technologies, methods, and approaches developed to meet the needs of this changing field

Heating Effects Through Harmonic Distortion on Electric Cables in the Built Environment

Under ideal circumstances, electric power supply voltage and current waveforms should be sinusoidal. However, this is very seldom the case in the built environment, due to the proliferation of non-linear loads. Examples of non-linear loads are those containing switched mode power supplies, reactors and electronic rectifiers/inverters. Common devices such as personal computers, fluorescent lighting, electric motors, variable speed drives, transformers and reactors and virtually all other electronic equipment are examples of non-linear loads. Non-linear loads are the norm in the built environment rather than the exception. Such loads produce complex current and voltage waves and simple spectral analysis of these complex waves shows that they can be represented by a wave at the fundamental power frequency plus other wave forms at integer and non-integer multiples of this frequency. These harmonics produce an overall effect called \u27Harmonic Distortion\u27 which can give rise to overheating in plant, equipment and the power cables supplying them, leading to reduced efficiency, operational life and sometimes failure. Over the last few decades, harmonic distortion in power supplies has increased significantly due to the increasing use of electronic components in industry and elsewhere. Buildings such as modern office blocks, commercial premises, factories, hospitals, etc.,contain equipment that generates harmonic loads as described above. Each item of equipment produces a unique harmonic signature and therefore a harmonic distortion which can be predicted if the equipment in use can be determined in advance. This thesis seeks to identify the harmonic signatures of different types of equipment commonly used and to predict the thermal loading effects on distribution cables caused by the skin and proximity effects of harmonic currents

Diseño de la planta propulsora de un buque oceanográfico

El objetivo del TFC es proyectar la planta propulsora de un buque oceanográfico. También se proyectarán los sistemas auxiliares a la propulsión tales como sistema de combustible, sistema de arranque por aire comprimido, sistema de refrigeración y sistema de ventilación en cámara de máquinas. Para ello será necesaria la determinación de las dimensiones principales del buque a partir de unas especificaciones y restricciones dadas por el armador, el cálculo de resistencia al avance, dimensionamiento y compartimentado de la cámara de máquinas, disposición de tanques y balance eléctrico del buque. Su interés reside en la particularidad de estos buques, el sistema propulsivo debe estar diseñado para diversas condiciones de navegación y en condiciones climáticas muy adversas. Por tanto, el problema abordado es encontrar el sistema propulsivo lo más fiable y polivalente posible