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

Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard

Uma revisão bibliométrica sobre a identificação de cargas similares em Smart Grid

In light of the need to consciously use energy resources for sustainable growth, the smart grid concept has served as a reference for the efficient use of such resources, especially the electric. However, the application of such concept in electrical installations requires the development of devices that allow the autonomous monitoring of electrical and electronic appliances in such installations. This article aims to carry out a bibliometric review on non-intrusive load monitoring methods to show the state of the art of this subject, that is, the main advances and obstacles to the development of this technology. A quantitative and qualitative analysis of the works related to the theme searched through the Web of Science database is performed. As result of such research, it is cited the observance of the relevance of the studies in this area, which is in full growth. It is also mentioned the fact that the theme is being investigated in developed countries, like Canada and the United States, as well as in developing countries, like Malaysia and India, which shows that there is a global concern in advancing in such a problem that independent of the nation's economic situation.Ante la necesidad de un uso consciente de los recursos energéticos para el crecimiento sostenible, el concepto Smart Grid ha servido de referencia para el uso eficiente de tales recursos, sobre todo el eléctrico. Sin embargo, la aplicación de tal concepto en las instalaciones eléctricas requiere el desarrollo de dispositivos que permitan el monitoreo autónomo de aparatos electroelectrónicos en tales instalaciones. Este artículo tiene como objetivo realizar una revisión bibliométrica sobre los métodos no intrusivos de monitoreo de cargas, a fin de mostrar el estado del arte de esta temática, es decir, los principales avances y obstáculos para el desarrollo de esa tecnología. Se realiza un análisis cuantitativo y cualitativo de los trabajos referentes al tema buscados vía base de datos Web of Science. Como resultado de dicha investigación, se observa la relevancia de los estudios en esa área, que está en pleno crecimiento. Se cita el hecho de que el tema está siendo investigado tanto en países desarrollados como Canadá y Estados Unidos, como en países en desarrollo, como Malasia e India, lo que muestra que existe una preocupación mundial en avanzar en tal problema que independe de la situación económica de la nación.Diante da necessidade de uso consciente dos recursos energéticos para o crescimento sustentável, o conceito Smart Grid tem servido de referência para o uso eficiente de tais recursos, sobretudo o elétrico. Entretanto, a aplicação de tal conceito nas instalações elétricas requer o desenvolvimento de dispositivos que permitam o monitoramento autônomo de aparelhos eletroeletrônicos em tais instalações. Este artigo tem como objetivo realizar uma revisão bibliométrica sobre os métodos não-intrusivo de monitoramento de cargas, a fim de mostrar o estado da arte dessa temática, isto é, os principais avanços e entraves para o desenvolvimento dessa tecnologia. É realizada uma análise quantitativa e qualitativa dos trabalhos referentes ao tema buscados via base de dados Web of Science. Como resultado de tal investigação, observa-se a relevância dos estudos nessa área, que está em pleno crescimento. Cita-se ainda o fato de o tema estar sendo investigado tanto em países desenvolvidos, como Canadá e Estados Unidos, quanto em países em desenvolvimento, como Malásia e Índia, o que mostra que existe uma preocupação mundial em se avançar em tal problema que independe da situação econômica da nação

Améliorations de méthodes de localisation de défauts pour les réseaux de distribution électrique

This thesis proposes to improve fault localization methods for electricalpower distribution networks. Transmission networks were quickly equipped with protectionand fault localization equipments. Indeed, faults on the transmission network need tobe dealt with quickly in order to avoid serious consequences. Unlike transmission networks,distribution networks have a minimal protection scheme. The smart grid developmentsbring new possibilities with the installation of new equipments giving access to many newvariables. The work presented in this thesis develop two fault localization method. Thefirst aims in using the equipment already installed (fault indicators) in order to isolatequickly and efficiently the zone concerned by the fault. The second method performs aprecise localization (in distance) of the different possible fault locations from the electricalmeasurements made on the network.Ces travaux proposent des améliorations de méthodes de localisation desdéfauts électriques sur les réseaux électriques de distribution. Les réseaux de transportont rapidement été instrumenté en élément de protection. En effet, un incident survenantsur le réseau de transport peut entrainer de graves conséquences s’il n’est pas traité rapidement.Les réseaux de distribution quand à eux possèdent un schéma de protectionminimal. Cependant le développement des smart grids (ou réseaux intelligents) amène denouvelles possibilités avec l’ajout d’équipements de mesures sur le réseau de distribution.Les travaux présentés dans cette thèse développent deux méthodes de localisation de défaut.La première permet de mieux utiliser l’équipement déjà en place (indicateurs depassage de défaut) afin d’isoler de manière rapide et fiable la zone concernée par le défaut.La deuxième permet une localisation précise (en distance) des différents lieux de défautspossibles à partir de mesures électriques

Arc fault protections for aeronautic applications: a review identifying the effects, detection methods, current progress, limitations, future challenges, and research needs

©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Arc faults are serious discharges, damaging insulation systems and triggering electrical fires. This is a transversal topic, affecting from residential to aeronautic applications. Current commercial aircrafts are being progressively equipped with arc fault protections. With the development of more electric aircrafts (MEA), future airliners will require more electrical power to enhance fuel economy, save weight and reduce emissions. The ultimate goal of MEAs is electrical propulsion, where fault management devices will have a leading role, because aircraft safety is of utmost importance. Therefore, current fault management devices must evolve to fulfill the safety requirements of electrical propelled aircrafts. To deal with the increased electrical power generation, the distribution voltage must be raised, thus leading to new electrical fault types, in particular arc tracking and series arcing, which are further promoted by the harsh environments typical of aircraft systems, i.e., low pressure, extreme humidity and a wide range of temperatures. Therefore, the development of specific electrical protections which are able to protect against these fault types is a must. This paper reviews the state-of-the-art of electrical protections for aeronautic applications, identifying the current status and progress, their drawbacks and limitations, the future challenges and research needs to fulfill the future requirements of MEAs, with a special emphasis on series arc faults due to arc tracking, because of difficulty in detecting such low-energy faults in the early stage and the importance and harmful effects of tracking activity in cabling insulation systems. This technological and scientific review is based on a deep analysis of research and conference papers, official reports, white papers and international regulations.This research was partially funded by the Ministerio de Ciencia e Innovación de España, grant number PID2020-114240RB-I00 and by the Generalitat de Catalunya, grant number 2017 SGR 967.Peer ReviewedPostprint (author's final draft

Real-Time Implementation and Evaluation of a Support Vector Machine Based Fault Detector and Classifier for Distribution Grids

Bridging the gap between theoretical modeling and practical implementation is essential in fault detection, classification, and location methods for modern distribution grids. Currently distribution grids are characterized by dispersed infeed and distributed power generation that render conventional protection settings more challenging, and, hence, new methods must be investigated to resolve these issues. In this paper, a novel framework capable of detecting and classifying faults in power distribution grids is presented. The proposed algorithm formulates a unique fault classification technique based on measurement samples of three-phase voltage and currents after the occurrence of a fault event in power distribution grid. Thereby, negative sequence components of three-phase voltage and current quantities are used for online fault detection that triggers a fault classification method based on a support vector machine. In order to simulate fault scenarios, a model of a reference distribution grid incorporating distributed generation is developed, simulated, and analyzed under fault conditions. For the final evaluation, the designed protection scheme is implemented on a Programmable Logic Controller connected to the model running on a real-time simulator hardware that provides voltage and current measurements. Thus experimental results are provided to demonstrate and prove the contribution of the algorithm in its ability to correctly identify and classify faults in modern distribution grids

AUTONOMOUS DC MICROGRID WITH SELF-CONFIGURABLE FEASIBILITY

Microgrids are power systems that work not only from the main power grid, but also in island mode operation. As each of the power sources and loads have voltage and current limitations, the autonomous microgrid should be able to control voltage and current levels while loads and sources are connected to the grid. Therefore, the microgrid bus voltage remains constant and power transfers safely. To configure an autonomous microgrid, the load and source type identification comes to mind. An autonomous microgrid needs to know the type of the electrical components which are going to be connected to the grid. In this study, by using voltage trend recognition, the type of the electrical device (DC power supply, battery, and load) is identified. Moreover, by recognizing the battery state of charge (SOC), the electrical power management of the microgrid is optimized. The experimental setup is able to detect the type of the electrical device (battery, voltage source or load) and then configures the DC microgrid to transfer power efficiently. By implementing PI controller and fuzzy method to control the DC microgrid, various cases in the microgrid such as load sharing, charging the battery, powering the different loads (uncharged battery, DC motor, and resistive loads) and importing new sources and xi loads are used to test the experimental setup of the DC microgrid and related power electronics converters. The experimental results demonstrate the validity and efficiency of the proposed system for the self-configurable autonomous DC microgrid

Load Monitoring and fault detection on DC micro grids using STFT based feature vectors

This thesis explores load monitoring on dc micro-grids specifically applied to Naval shipboard power systems. More electronic loads are being placed on Naval ships and, increasingly, more of these loads are pulsed-power in nature; drawing pulsating current from the grid. This presents a challenge for conventional fault monitoring devices as many fault currents are also pulsating in nature and can be difficult to differentiate from a desirable pulse event. Short-time Fourier transform is the technique preferred in this work for spectral analysis of the current signals. In addition to event based monitoring, another unsupervised control is being employed to continuously check the frequency content of the current to look for arcing faults caused by loose electrical connections. The objective of the dissertation is to develop a load monitoring algorithm that records the current drawn by these loads and is able to detect events and differentiate between desirable events and faults using their frequency content in run-time. The algorithm is realized on an micro-controller unit and validated on a low-voltage dc test-bed