A survey of sag monitoring methods for power grid transmission lines

The transmission line is a fundamental asset in the power grid. The sag condition of the transmission line between two support towers requires accurate real-time monitoring in order to avoid any health and safety hazards or power failure. In this paper, state-of-the-art methods on transmission line sag monitoring are thoroughly reviewed and compared. Both the direct methods that use the direct video or image of the transmission line and the indirect methods that use the relationships between sag and line parameters are investigated. Sag prediction methods and relevant industry standards are also examined. Based on these investigation and examination, future research challenges are outlined and useful recommendations on the choices of sag monitoring methods in different applications are made

Numerical Investigations of the Thermal State of Overhead Lines and Underground Cables in Distribution Networks

As part of extensive activities on the reduction of CO2 emissions, a rapid expansion of power generation using new more fuel efficient technologies (large, medium and embedded scale with combined heat and power (CHP) projects) and renewable energy (wind, biomass, solar PV) is currently taking place in numerous European countries, including the UK. The research presented in this thesis is a part of a UK government funded project, which aims to find answers to how to accommodate increased renewable energy into the distribution network. Current ratings, which are limited by the temperature of the conductors used in the distribution network, are based on worst case scenario conditions and are conservative. The temperature limits can be lifted if one takes into consideration the dynamic changes in the surrounding environmental conditions of the conductors. Implementation of real-time thermal rating of existing power systems could result in greater installed capacities of distributed generation (DG). This research aims to provide new insights into the thermal state of overhead line conductors (OHL) and underground cables (UGC) by using Computational Fluid Dynamic methods. An algorithm consists of building the geometry of the calculation domain, meshing, choosing a model, inputting initial conditions, initiation of the calculation, and analysing results. A part of the UK power system was chosen by Scottish Power Energy Networks for monitoring essential data of OHL conductors in order to validate results of the temperatures of the conductors

Design of resource to backbone transmission for a high wind penetration future

In a high wind penetration future, transmission must be designed to integrate groups of new wind farms with a high capacity inter-regional ``backbone transmission system. A design process is described which begins by identifying feasible sites for future wind farms, identifies an optimal set of those wind farms for a specified future, and designs a reliable low-cost ``resource to backbone collector transmission network to connect each individual wind farm to the backbone transmission network. A model of the transmission and generation system in the state of Iowa is used to test these methods, and to make observations about the nature of these resource to backbone networks

Aluminum Conductor Steel-Supported Conductors for the Sustainable Growth of Power Line Capacity:A Review and Discussion

Industrial development and population growth have increased the need for higher-capacity power transmission lines. Aluminum conductor steel-supported (ACSS) conductors, a type of high-temperature low-sag (HTLS) conductor, are now widely used in new designs and reconductoring applications. ACSS conductors are preferred over traditional aluminum conductor steel-reinforced (ACSR) conductors due to their high strength, low sag, and excellent thermal stability. These attributes have garnered significant interest from researchers, engineers, and manufacturers. This paper provides a comprehensive review of the structure, properties, testing methods, and environmental behavior of ACSS conductors

Development, optimization and experimental validation of smart devices for substations and power transmission lines

Tesi amb menció de Doctorat Industrial (Generalitat de Catalunya)Tesi en modalitat de compendi de publicacionsIn reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Universitat Politècnica de Catalunya's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink(English) In recent years, there has been a significant increase in the growth of electricity demand. This electricity demand requires retrofitting of lines or exploiting the maximum capacity of existing power lines. In addition, substation connectors are the critical components of power systems since the failure of substation connectors can lead to serve power outages and significantly affect the power transmission efficiency. Therefore, it is vital to have real-time information on key elements of electrical systems, such as connectors and conductors, in order to ensure the reliability and efficiency of power transmission systems. To this end, the Smartconnector project aims to combine ICT (Information and Communication Technologies), IoT (Internet of Things) and data-driven technologies to estimate the state of health of substation connectors and take advantage of the maximum capacity of lines. Over the past few years, several research projects have been carried out to develop a smart high voltage connectors prototype, Smartconnector, in order to collect and wirelessly transmit information from power connectors in real time. Moreover, a prediction model has been proposed to utilize the collected data to separately predict the remaining useful life of connectors. However, improvements, experimental validation and field application are still needed to verify the reliability and feasibility of the Smartconnector prototype. In addition, field application of the IoT device is required for both connectors and conductors. This thesis is dedicated to the development, improvement, and experimental validation of the IoT prototype and the extension of its application to further increase the efficiency of power transmission systems. It is divided into two cores, which include the optimization of the Smartconnector prototype, and the extension of its application. This thesis improves the power management system, which helps to prolong the lifetime of the device. This improvement is based on thermal energy harvesting together with the energy balance strategy. Also, it develops statistical filtering algorithms for data processing. The proposed algorithms are finally implemented on the embedded system of the Smartconnector device, ensuring the accuracy of the continuous measurements. This thesis also focuses on the application of the Smartconnector for the dynamic monitoring of the line capacity considering weather conditions. In conclusion, this thesis aims to provide improvements and developments for the Smartconnector, as well as to open its application to other fields.(Español) En los últimos años se ha producido un aumento significativo del crecimiento de la demanda de electricidad. Este crecimiento requiere el reequipamiento de las líneas o el aumento de la capacidad de las líneas eléctricas existentes. Además, los conectores de subestación son componentes críticos, ya que su fallo de los conectores puede provocar cortes de servicio y afectar significativamente a la eficiencia de la transmisión de energía. Por lo tanto, es vital disponer de información en tiempo real sobre elementos clave de los sistemas eléctricos, como conectores y conductores, para garantizar la fiabilidad y eficiencia de los sistemas de transmisión de energía. Con este fin, el proyecto Smartconnector pretende combinar las TIC (Tecnologías de la Información y la Comunicación), el IoT (Internet of Things) y las tecnologías basadas en datos para estimar el estado de salud de los conectores de las subestaciones y aprovechar al máximo la capacidad de las líneas. En los últimos años, se han llevado a cabo varios proyectos de investigación para desarrollar un prototipo de conectores inteligentes de alta tensión, Smartconnector, con el fin de recopilar y transmitir de forma inalámbrica información de los conectores de potencia en tiempo real. Además, se ha propuesto un modelo de predicción que utiliza los datos recogidos para predecir por separado la vida útil restante de los conectores. Sin embargo, aún son necesarias mejoras, validación experimental y aplicación sobre el terreno para verificar la fiabilidad y viabilidad del prototipo Smartconnector. Además, es necesaria la aplicación sobre el terreno del dispositivo IoT tanto para los conectores como para los conductores. Esta tesis está dedicada al desarrollo, mejora y validación experimental del prototipo IoT y la extensión de su aplicación para aumentar aún más la eficiencia de los sistemas de transmisión de energía. Esta tesis se divide en dos partes, que incluye la optimización del prototipo Smartconnector y la extensión de su aplicación. Esta tesis mejora el sistema de gestión de energía, lo que ayuda a prolongar la vida útil del dispositivo. Dicha mejora, se basa en la captación de energía térmica junto con la estrategia de balance energético. Asimismo, esta tesis presenta desarrollos de algoritmos de filtrado estadístico para el procesamiento de datos. Los algoritmos propuestos se implementan finalmente en el sistema integrado del dispositivo Smartconnector, asegurando la precisión de las medidas continuas. Esta tesis también se centra en la aplicación del Smartconnector para la monitorización dinámica de la capacidad de la línea teniendo en cuenta las condiciones meteorológicas. En conclusión, esta tesis pretende aportar mejoras y desarrollos para el Smartconnector, así como abrir su aplicación a otros campos.Postprint (published version

Machine Learning Tool for Transmission Capacity Forecasting of Overhead Lines based on Distributed Weather Data

Die Erhöhung des Anteils intermittierender erneuerbarer Energiequellen im elektrischen Energiesystem ist eine Herausforderung für die Netzbetreiber. Ein Beispiel ist die Zunahme der Nord-Süd Übertragung von Windenergie in Deutschland, die zu einer Erhöhung der Engpässe in den Freileitungen führt und sich direkt in den Stromkosten der Endverbraucher niederschlägt. Neben dem Ausbau neuer Freileitungen ist ein witterungsabhängiger Freileitungsbetrieb eine Lösung, um die aktuelle Auslastung des Systems zu verbessern. Aus der Analyse in einer Probeleitung in Deutschland wurde gezeigt, dass einen Zuwachs von ca. 28% der Stromtragfähigkeit eine Reduzierung der Kosten für Engpassmaßnahmen um ca. 55% bedeuten kann. Dieser Vorteil kann nur vom Netzbetreiber wahrgenommen werden, wenn eine Belastbarkeitsprognose für die Stromerzeugunsgplanung der konventionellen Kraftwerke zur Verfügung steht. Das in dieser Dissertation vorgestellte System prognostiziert die Belastbarkeit von Freileitungen für 48 Stunden, mit einer Verbesserung der Prognosegenauigkeit im Vergleich zum Stand-der-Technik von 6,13% in Durchschnitt. Der Ansatz passt die meteorologischen Vorhersagen an die lokale Wettersituation entlang der Leitung an. Diese Anpassungen sind aufgrund von Veränderungen der Topographie entlang der Leitungstrasse und Windschatten der umliegenden Bäume notwendig, da durch die meteorologischen Modelle diese nicht beschrieben werden können. Außerdem ist das in dieser Dissertation entwickelte Modell in der Lage die Genauigkeitsabweichungen der Wettervorhersage zwischen Tag und Nacht abzugleichen, was vorteilhaft für die Strombelastbarkeitsprognose ist. Die Zuverlässigkeit und deswegen auch die Effizienz des Stromerzeugungsplans für den nächsten 48 Stunden wurde um 10% gegenüber dem Stand der Technik erhöht. Außerdem wurde in Rahmen dieser Arbeit ein Verfahren für die Positionierung der Wetterstationen entwickelt, um die wichtigsten Stellen entlang der Leitung abzudecken und gleichzeitig die Anzahl der Wetterstationen zu minimieren. Wird ein verteiltes Sensornetzwerk in ganz Deutschland umgesetzt, wird die Einsparung von Redispatchingkosten eine Kapitalrendite von ungefähr drei Jahren bedeuten. Die Durchführung einer transienten Analyse ist im entwickelten System ebenfalls möglich, um Engpassfälle für einige Minuten zu lösen, ohne die maximale Leitertemperatur zu erreichen. Dieses Dokument versucht, die Vorteile der Freileitungsmonitoringssysteme zu verdeutlichen und stellt eine Lösung zur Unterstützung eines flexiblen elektrischen Netzes vor, die für eine erfolgreiche Energiewende erforderlich ist

Accurate location of high impedance and temporary faults in radial distribution networks using distributed travelling wave observers

This thesis addresses a novel method for fault location in radial distribution networks and provides a new vision for the optimal deployment of synchronised voltage travelling wave (TW) observers in distribution networks. The proposed method can locate high impedance and temporary faults. The delay effect of transformers is demonstrated by theory and laboratory tests. A new method to eliminate the transformer’s effect on the accuracy of the fault location algorithm is presented

FEASIBILITY STUDY TO IMPLEMENT AN HIGH VOLTAGE DIRECT CURRENT TRANSMISSION LINK

Práce se zabývá návrhem přenosového vedení zvláště vysokého stejnosměrného napětí pro dopravu elektřiny mezi Německem a Rakouskem přes území ČR.The purpose of this thesis is to provide comprehensive information of HDVC transmission and to suggest a study to implement an HVDC link.The first part of the thesis provides a basic description of the technology, advantages, and disadvantages related to the dc transmission of electrical energy. The thesis also shows a basic proposed design model of HVDC link with different variants. The calculations of general parameters and estimated cost are presented. Subsequently, the variants are compared against them