An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

Magnetics in Smart Grid

This journal issue contain selected papers from the Asia-Pacific Data Storage Conference (APDSC'13)A revolution in power transmission and distribution, driven by environmental and economic considerations, is occurring all over the world. This revolution is spearheaded by the development of the smart grid. The smart grid is bringing profound change to both the power systems and many related industries. This paper reviews the development of the smart grid and its correlation with magnetics, including electromagnetic compatibility issue, magnetic-field-based measurement/monitoring, and magnetic energy storage/conversion. The challenge to the field of magnetics and the usage of the cutting edge magnetics technology in the development of the smart grid are discussed. This paper enables researchers in the magnetics community to be acquainted with the progress in the smart grid and inspires innovative applications of state-of-the-art magnetics technologies in the smart grid.published_or_final_versio

LCC-HVDC Connection of Offshore Wind Farms With Reduced Filter Banks

Despite being more efficient, line commutated converter-HVDC links for the connection of large offshore wind farms have ac-filter bank size as one of their main drawbacks. This paper shows how the HVDC rectifier filter banks can be substantially reduced by taking advantage of the additional control possibilities offered by the use of wind turbines with fully rated converters. PSCAD simulations validate wind farm and diode rectifier HVDC link operation with a capacitor and filter bank five times smaller than its usual value. The proposed control algorithm allows for good harmonic and reactive power sharing between the different wind turbines. As the reduced capacitor bank operation leads to a redistribution of harmonic and reactive currents, an efficiency study has been carried out to evaluate the new power loss distribution with the reduced filter banks

Grid integration of variable renewable energies in Ghana: assessment of the impact on system stability

This research analyses the impact of renewable energies (RE) generation in Ghana’s national interconnected transmission system (NITS) and how its stability is affected. Integrating RE, particularly solar and wind in Ghana’s power system has been discussed at the national level with the intention to diversify the energy mix and reduce the dependency on thermal energy. RE integration introduces operational and infrastructural challenges in Ghana’s network, to which novel measures are required. Using the DIgSILENT PowerFactory simulation tool and MATLAB, simulation scenarios are created to capture diverse network conditions including different RE penetration levels, load demand and infrastructural expansion for three separate years. The ‘optimum’ penetration level of RE in the NITS considering voltage and loading limits is also identified using optimization techniques. The simulation results show that the target scenario is the most prone to both static and dynamic voltage instability. The transient stability analysis however reveals the post-target scenario to be unstable. Furthermore, methods of optimization are used to determine the reactive power deficient nodes in the NITS, which serve as the basis for the stability enhancement measures. The simulations and analysis additionally indicate that implementing the proposed measures indeed enhances the stability of the NITS. Finally, this research shows that RE integration is ‘technically’ feasible in Ghana if the required network reinforcements and operational changes are accordingly considered

Implementation of Pilot Protection System for Large Scale Distribution System like The Future Renewable Electric Energy Distribution Management Project

abstract: A robust, fast and accurate protection system based on pilot protection concept was developed previously and a few alterations in that algorithm were made to make it faster and more reliable and then was applied to smart distribution grids to verify the results for it. The new 10 sample window method was adapted into the pilot protection program and its performance for the test bed system operation was tabulated. Following that the system comparison between the hardware results for the same algorithm and the simulation results were compared. The development of the dual slope percentage differential method, its comparison with the 10 sample average window pilot protection system and the effects of CT saturation on the pilot protection system are also shown in this thesis. The implementation of the 10 sample average window pilot protection system is done to multiple distribution grids like Green Hub v4.3, IEEE 34, LSSS loop and modified LSSS loop. Case studies of these multi-terminal model are presented, and the results are also shown in this thesis. The result obtained shows that the new algorithm for the previously proposed protection system successfully identifies fault on the test bed and the results for both hardware and software simulations match and the response time is approximately less than quarter of a cycle which is fast as compared to the present commercial protection system and satisfies the FREEDM system requirement.Dissertation/ThesisM.S. Electrical Engineering 201

Harmonic Allocation to Major Loads in Transmission Systems

A few decades ago, harmonic levels in electricity transmission networks were relatively low due to limited harmonic loads (such as renewable generation), low emissions from bulk supply points, high levels of synchronous generation and absorption from connected loads. Various international publications have forecasted that by 2030 many power systems around the world would have as high as 30% of renewable generation, e.g. solar and wind plants, which produce significant harmonics, and more than 60% increase in other harmonic producing loads (industrial, farming and residential equipment). This is coupled with the expected retirement of a large number of fossil-fuelled synchronous generators. Accordingly, growth in harmonic levels in the transmission network is anticipated. The Australian power system landscape has already changed and will continue to move rapidly towards having more renewable energy sources and power electronic loads. Recently, state governments throughout Australia have confirmed their support for the development of Renewable Energy Zones (REZ), i.e. areas with high concentrations of renewable energy sources. In August 2020, the Australian Energy Market Operator (AEMO) published the Integrated System Plan (ISP), which provides a 20-year roadmap for the National Electricity Market (NEM) through the energy transition period to 2040. The ISP includes a 63% reduction in coal-fired synchronous generation, a 200% increase in Distributed Energy Resources and a 75% increase in solar and wind plants. These new technologies bring with them a wide range of harmonic issues; however, there has been no significant updates in the harmonic management of Australian transmission systems. In particular, the latest version of the Australian National Electricity Rules (NER), as of 17 September 2020, still referenced the 20 years old Australian and New Zealand Standard, i.e. AS/NZS 61000.3.6:2001. Transmission System Operators (TSOs) rely heavily on existing standards and guidelines, which have increasingly become less relevant and less effective for modern power systems. Urgent review and improvement of existing standards and guidelines are needed to avoid unnecessary impediment to the transition plan of power systems towards modern loads and higher renewable penetration platforms

Dependence of Magnetisation near Saturation on Alloying Content in Ferromagnetic Steel

This paper shows that there is strong dependence of saturation magnetization on the alloying content in ferromagnetic steels. This dependence was used to determine the cross-sectional areas of the commercial non-oriented and grain-oriented silicon-iron steels. The relation between magnetization near saturation and the contents of silicon and aluminum for a large number of steel samples was experimentally obtained using an air-cored magnetizing system. The influence of the approach to magnetic saturation and its use in the determination of the cross-sectional area of electrical steel strips using the saturation magnetization method was estimated. Standard deviation (SD) of cross-sectional area obtained using the saturation magnetization method was on the order of 0.14%. SD for using conventional technique was also on the similar order of ~0.11%

Standards review of distributed generation and impact analysis of renewable penetration in a remote microgrid. Case study: San Cristobal Island, Galapagos Archipelago

El presente Trabajo de Fin de Grado pretende realizar un estudio de las reglamentaciones de Generación Distribuida y la planificación energética de la Isla San Cristóbal (Galápagos, Ecuador) para abordar tres retos asociados a la Generación Distribuida. Estos retos son el control de la calidad de la energía inyectada por los generadores, su viabilidad económica y su capacidad de almacenaje energético. Para tratar el primer reto se ha realizado un estudio de las limitaciones técnicas que se imponen a estos generadores a través de 37 Regulaciones. Se han seleccionado los parámetros técnicos a través de los cuales se regula la calidad de la energía y tras su explicación, se ha realizado una comparativa de cómo se tratan estos parámetros en cada regulación. Para el estudio de los otros dos retos, se han realizado simulaciones mediante el software Homer Pro de la implementación de Generación Distribuida en la Isla de San Cristóbal. Estas simulaciones considerarán tres escenarios diferentes, el primero basado en la situación actual de la Isla, el segundo en la posibilidad de abastecimiento por renovables en un 50% y el último considera el completo abastecimiento por renovables. Dado que el software proporciona resultados económicos además de eléctricos, es posible analizar los dos retos a través de éstos. Por un lado, los resultados de la comparativa regulatoria demuestran que aún no existe un consenso respecto a estos sistemas, lo cual supone un inconveniente para el desarrollo de esta tecnología. Mediante las simulaciones se han obtenido resultados inesperados en relación a la viabilidad económica, puesto que una mayor penetración de renovables crearía un resultado más favorable. Por otro lado, ha quedado demostrado que la tecnología actual de almacenamiento supone un lastre para que escenarios de Generación Distribuida con alta penetración de renovable sean competitivos energética y económicamente.This Bachelor Thesis aims to perform a study of the Distributed Generation regulations and an electric planification of San Cristobal Island (Galapagos, Ecuador) to analyze three challenges related with the Distributed Generation. These challenges are power quality of the service provided by the generators, its economic feasibility, and its power storage capacity. To deal with the first challenge, a study of the technical requirements imposed on the generators through 37 different regulations has been performed. The most relevant technical parameters through which the standards control the energy quality delivered have been selected, and after explaining them, a comparison among the standards has been done. To study the other two challenges, different simulations of the implementation of Distributed Generation in San Cristobal Island have been performed with the software Homer Pro. These simulations consider three different scenarios, the first one is the actual configuration of the island, the second one considers a service of 50% renewable energies, and the last one is a scenario totally supplied by renewables. As the software displays the economic and electric results, it will be possible to address both challenges through it. The regulation comparison has demonstrated that there is a lack of harmonization among the standards, which can put at risk the development of this technology. The simulations have shown unexpected results in regard of the economic feasibility, as the scenario which considered half of the supply coming from renewables was more competitive than the diesel fueled one. With respect the storage capacity, it has been proven that the current technology is not enough developed, and it is an impediment for the distributed generation to be competitive.Ingeniería en Tecnologías Industriale