Network Security in Smart Grids

Akıllı şebekeler, elektrik enerjisinin kesintisiz ve en az maliyetle kullanıcıya arz edilmesini mümkün kılmakta ve elektrik enerjisi dağıtım şebekelerinin özelleşmesi ile birlikte enerji otomasyonu çözümlerinde daha fazla önem kazanmaktadır. Enerji otomasyonu çözümlerinde siber güvenlik, uzaktan erişilebilir ve kontrol edilebilir sistemlerde teknolojinin hızla gelişmesi ile daha da önemli olmaktadır. Bir enerji şebekesinin siber güvenliğinin sağlanması için, Siemens bünyesindeki Spectrum Power çözümlerine entegre olarak siber güvenlik çözümleri geliştirilmektedir. Bu çözümlerle temel olarak ağ üzerinde kurulan tüm bağlantı oturumları analiz edilerek her bir oturumun güvenilir olup olmadığı tespit edilebilmekte, ayrıca tüm oturumlar loglanabilmekte ve güvenli olmayan oturumlar sonlandırılabilmektedir. Böylece enerjinin kesintisiz ve güvenilir bir şekilde en uçtaki kullanıcıya ulaşması sağlanabilmektedir

Power system applications of fiber optics

Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section reviews fibers as components of communication systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electric equipment in a high voltage situation, potentially replacing expensive high voltage low power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples. This work is described

Development and Experimentation of Traceable Characterization Methods for Medium Voltage Instrument Transformers for PQ and PMU Applications

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

Infrastructure for the metrology for HVDC energy supply

Im Rahmen dieser Arbeit wurde die Infrastruktur für die HGÜ-Energiemesstechnik an der Physikalisch-Technischen Bundesanstalt aufgebaut. Im Fokus stehen hier die für die Hochspannungs-Gleichstromübertragung notwendigen Möglichkeiten zur Rückführung von Sensoren und Messgeräten auf nationale Normale, um das gesetzliche Messwesen sowie die korrekte Messung und Abrechnung der transportierten elektrischen Energie im Bereich der HGÜ sicherzustellen. Dies beinhaltet Messeinrichtungen für hohe Gleichstromwandler bis ± 2.000 ADC und Gleichspannungsteiler bis ± 300.000 VDC. Die verwendeten Signalformen für die Hochspannungs- und Hochstrommessungen beinhalten dabei neben den grundlegenden DC-Komponenten auch überlagerte Wechselanteile im Frequenzbereich bis 20 kHz, welche als Nachbildung der reellen Signalverzerrungen in der HGÜ aufgrund von Umrichtern dienen. Die überlagerte Erzeugung und korrekte Erfassung solcher Mischsignale bilden den Kern dieser Arbeit. Die durch die gezielten Verzerrungen hervorgerufenen Störungen der DC-Sensoren sind Mittelpunkt der wissenschaftlichen Untersuchungen mit Hilfe der aufgebauten Messeinrichtungen. Desweiteren wird die Kalibrierung von DC-Leistungs-messgeräten und DC-Energiezählern auf Kleinsignalebene mit Mischströmen und ?spannungen in dieser Arbeit behandelt. Dabei werden sowohl herkömmliche analoge Messgeräte als auch neuartige digitale Ausführungen dieser berücksichtigt. Abschließend werden die erreichten Messunsicherheiten der aufgebauten Messeinrichtungen unter Verwendung der geltenden Richtlinien präsentiert. Die Grundzüge einer metrologischen Infrastruktur für die HGÜ-Metrologie an der PTB sind im Rahmen dieser Arbeit und des Forschungsprogramms European Metrology Research Programme (EMRP) geschaffen worden. In Zusammenarbeit mit dem Institut für Hochspannungstechnik und Elektrische Energieanlagen der Technischen Universität Braunschweig wurde diese Arbeit gezielt auf die Problematik der fehlenden metrologischen Infrastruktur auf dem Gebiet der HGÜ-Messtechnik ausgelegt.Within the scope of this work, the infrastructure of "Metrology for HVDC energy supply" has been set up at the Physikalisch-Technische Bundesanstalt. Hereby, the activities are focused on the capacities which are necessary in the field of high-voltage direct current (HVDC) transmission to enable the traceability of sensors and measuring devices to national standards for the purposes of legal metrology and in order to ensure the correct measurement and billing of the electric energy transported within the HVDC. This includes measuring equipment for DC current transducers up to ± 2,000 ADC and DC voltage dividers up to ± 300,000 VDC. The signal forms used for high-voltage and high-current measurements thereby contain – apart from the basic DC components – also superposed AC components in the frequency range up to 20 kHz which serve as an emulation of the real signal distortions in the HVDC due to converters. The superposed generation and correct acquisition of such mixed signals represent the core of this work. The disturbances of the DC sensors caused by the targeted distortions are the focus of the scientific investigations carried out with the aid of the measuring facilities set up. Furthermore, the calibration of DC power measuring instruments and of DC energy meters at the low-signal level with mixed currents and mixed voltages is dealt with in this work. Hereby, both conventional, analogue and novel, digital measuring instruments will be considered. In conclusion, the measurement uncertainties attained with the measuring facilities set up will be presented using the directives currently valid. The main features of a metrological infrastructure for HVDC metrology at PTB have been provided within the scope of this work and of the European Metrology Research Programme (EMRP). In cooperation with the Institut für Hochspannungstechnik und Elektrische Energieanlagen (Institute of High-voltage Technology and Electric Power Systems) of the Technische Universität Braunschweig, this work was specially designed to solve the issue of the lack of a metrological infrastructure in the field of HVDC metrology

Selected Papers from 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020)

The 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020) was held on 6–10 September 2020 in Beijing, China. The conference was organized by the Tsinghua University, China, and endorsed by the IEEE Dielectrics and Electrical Insulation Society. This conference has attracted a great deal of attention from researchers around the world in the field of high voltage engineering. The forum offered the opportunity to present the latest developments and different emerging challenges in high voltage engineering, including the topics of ultra-high voltage, smart grids, and insulating materials

Design and Control of Power Converters for High Power-Quality Interface with Utility and Aviation Grids

Power electronics as a subject integrating power devices, electric and electronic circuits, control, and thermal and mechanic design, requires not only knowledge and engineering insight for each subarea, but also understanding of interface issues when incorporating these different areas into high performance converter design.Addressing these fundamental questions, the dissertation studies design and control issues in three types of power converters applied in low-frequency high-power transmission, medium-frequency converter emulated grid, and high-frequency high-density aviation grid, respectively, with the focus on discovering, understanding, and mitigating interface issues to improve power quality and converter performance, and to reduce the noise emission.For hybrid ac/dc power transmission,• Analyze the interface transformer saturation issue between ac and dc power flow under line unbalances.• Proposed both passive transformer design and active hybrid-line-impedance-conditioner to suppress this issue.For transmission line emulator,• Propose general transmission line emulation schemes with extension capability.• Analyze and actively suppress the effects of sensing/sampling bias and PWM ripple on emulation considering interfaced grid impedance.• Analyze the stability issue caused by interaction of the emulator and its interfaced impedance. A criterion that determines the stability and impedance boundary of the emulator is proposed.For aircraft battery charger,• Investigate architectures for dual-input and dual-output battery charger, and a three-level integrated topology using GaN devices is proposed to achieve high density.• Identify and analyze the mechanisms and impacts of high switching frequency, di/dt, dv/dt on sensing and power quality control; mitigate solutions are proposed.• Model and compensate the distortion due to charging transition of device junction capacitances in three-level converters.• Find the previously overlooked device junction capacitance of the nonactive devices in three-level converters, and analyze the impacts on switching loss, device stress, and current distortion. A loss calculation method is proposed using the data from the conventional double pulse tester.• Establish fundamental knowledge on performance degradation of EMI filters. The impacts and mechanisms of both inductive and capacitive coupling on different filter structures are understood. Characterization methodology including measuring, modeling, and prediction of filter insertion loss is proposed. Mitigation solutions are proposed to reduce inter-component coupling and self-parasitics

Protection contre les courts-circuits des réseaux à courant continu de forte puissance

Dans le domaine du transport de l'électricité, les qualités intrinsèques des réseaux alternatifs s'estompent devant la difficulté imposée par le transport de la puissance réactive lorsque les lignes aériennes ou, plus particulièrement, les câbles souterrains ou sous-marins atteignent des longueurs critiques. Dans le cadre des réflexions visant à exploiter au mieux les énergies renouvelables d'origine éolienne off-shore ou hydrolienne, l'hypothèse de la création d'un réseau électrique à haute tension continue pour acheminer ces énergies jusqu'aux centres de consommation est considérée. Ce travail de thèse est en lien avec le projet européen TWENTIES (Transmission system operation with large penetration of Wind and other renewable Electricity sources in Networks by means of innovative Tools and Integrated Energy Solutions, ref 249812), financé dans le cadre du programme FP7 de la Commission Européenne. Ces travaux traitent de la protection des réseaux à courant continu contre les défauts d'isolement dans les câbles et au niveau des jeux de barre. L'étude se concentre sur des réseaux multi-terminaux bouclés et/ou maillés, et propose d'étudier la faisabilité d'un plan de protection comportant un algorithme principal et un secours en cas de défaillance d'un disjoncteur.In the area of power transmission grids, the inherent qualities of alternative current networks fade behind the difficulty imposed by the transmission of the reactive power when overhead lines or, particularly, underground or undersea cables reach critical lengths. As part of thought aimed for operate at best renewable energy resources, namely wind or marine resources, the assumption of the creation of a high voltage direct current power grid to dispatch those energies to the consumption centers is considered. This Ph.D work is linked to the European project TWENTIES (Transmission system operation with large penetration of Wind and other renewable Electricity sources in Networks by means of innovative Tools and Integrated Energy Solutions, ref 249812), funded as a part of the 7th framework program of the European Commission. This work deal with the protection of DC grids against insulation faults occurring in the cables or at a busbar. The study focusses on meshed and/or looped multi-terminal grids, and proposes to study the feasibility of a protection plan including a main protection algorithm and a backup in case of breaker failure.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Non-conventional sensors for measuring partial discharge under DC electrical stress

Partial discharge (PD) is a micro discharge that occurs in defected regions within the insulating media. As these discharges are the main culprits that cause dielectric material aging, PD measurements have been used for assessing insulating materials, including solids, liquids, and gases for power applications. There are various methods and sensors available for measuring PD sensitive to specific characteristics and operable over a wide range of frequencies. Most PD measurement techniques provide patterns that enable PD interpretation more comfortable for users. For example, in AC applications, the phase-resolved partial discharge (PRPD) technique provides identifiable patterns for distinguishing various types of PDs. However, the establishment of meaningful patterns to multiple types of PD in DC systems requires more sensitive and accurate measurements of individual PD pulses with noise rejection functionality due to the lack of phase-resolved information. Investigating of the transient phenomena such as individual PD pulses requires well-designed circuits with sufficiently large bandwidths. Waveshapes can be easily disturbed by background noise and deformed by the frequency response of measuring circuits and data acquisition systems (DAQ). Noises are unwanted disturbances that could be suppressed by suitable filters or mathematical methods. Measurement circuits and DAQ systems consist of transmission lines, sensors, cables, connectors, DAQ hardware, and oscilloscopes. Therefore, matching the impedance of all components guarantees a reflectionree path for traveling signals and addresses most of the challenges relevant to transient measurements. In this dissertation, we proposed and designed an appropriate testbed equipped with high bandwidth transmission line and electromagnetic field sensors suitable for investigating PD under DC electrical stresses. We comprehensively used finite element analysis simulations through the COMSOL Multiphysics software to design the dimensions and evaluate the frequency response of the testbed, transmission line, and electromagnetic sensors. Furthermore, based on the new testbed, DC PD measurements were performed using conventional and non-conventional sensors. Finally, various types of DC PD were statistically classified based on the proposed testbed