Now showing 1 - 10 of 46
  • Publication
    Seam carving for content-aware wide-angle projection of panoramic photography
    (Irish Pattern Recognition & Classification Society, 2018-08-31) ;
    This paper presents a new method for the wide-angle projection of panoramic photographic imagery. The proposed methodology uses seam-carving techniques to improve the conformality of an equal-area projection of an image. Fundamentally, any wide-angle projection from a omnidirectional scene will contain distortion, however the aim of this method is to strategically introduce this distortion in areas of low salience in the image, to better preserve the appearance of the important content.
  • Publication
    Effect of energy harvesting network reactive support on transmission system voltage performance
    It is common to operate distributed generators (DGs) at fixed inductive power factors to overcome voltage rise constraints on distribution networks. This approach increases distribution system reactive power demand, which may strain transmission system reactive power resources at times of system-wide high DG output, particularly if such output displaces synchronous generators. If a number of adjacent DGs are connected to a transmission node in a clustered fashion via a dedicated energy harvesting network (EHN), it is possible to characterise their aggregated reactive power capability as a form of virtual power plant. Such a characterisation will be provided in this paper. The aggregated capability may readily be included in transmission system models. This work will explicitly compare the transmission system voltage-control performance of EHN reactive capability with that of traditional synchronous plant.
  • Publication
    Validating Two Novel Equivalent Impedance Estimators
    Certain approaches to appraising voltage stability use an equivalent impedance to characterise the wider power system. This letter proposes two newways of inferring an appropriate equivalent impedance from a powersystem's admittance matrix. Continuation power flow simulations are used to validate the quality of the new estimators, and to benchmark them against some extant approaches.
  • Publication
    The role of the ERC-20 token standard in a financial revolution: the case of Initial Coin Offerings
    (IEC-IEEE-KATS, 2018-05)
    The year of 2017 saw a surge of interest in a curious new way to raise capital: the 'Initial Coin Offering' (ICO). In this style of crowdfunding, investors exchange a general-purpose cryptocurrency, such as Bitcoin (BTC) or Ethereum (ETH), for a branded and special-use blockchain token, which somehow underpins or represents the project that is being funded. Billions of dollars worth of capital has already been raised through these schemes, and these huge transfers have motivated diverse, and often skeptical, commentary. However, the technical standards which underpin these schemes have often passed unremarked, even though they were, arguably, the catalyst for the huge growth witnessed in this sector. The present work will elucidate how an informal standard for smart contracts on the Ethereum blockchain, labelled ERC-20, has enabled the wide proliferation of special purpose fundraising tokens. Crucially, the ERC-20 standard allows frictionless interoperability, so that any compliant Ethereum wallet software can transact and monitor the full range of compliant tokens. In this way, the short and rather dry ERC-20 document allows any Ethereum wallet to control a diverse portfolio of token investments, and it is precisely this interoperability that has permitted the vast capital transfers of the ICO era. The present work will briefly survey the short history of this technology and will discuss some implications that this disruption presents for technical standardisation bodies.
  • Publication
    All-Island Substation Connectivity Diagram v1.0
    In 1931, Harry Beck created the iconic London Underground tube map. By distorting the exact geography of the city, and insisting on only 90° or 45° angles, he created a legible display that made the connections between tube stations intuitive and tangible. Notably, it seems Beck’s familiarity with circuit schematics inspired his iconic tube map. With our diagram we try to come full circle: can transit maps inspire a new way to look at the circuits that make up the Irish power system? This diagram was iteratively built up over the course of a nine month collaboration between Dr. Paul Cuffe (UCD) and Dr. Pádraig Daly and others in Eirgrid. A key motivation was to aid communication with non-technical stakeholders: for instance, to explain why it might be necessary to build a new powerline to accommodate more wind power. The main challenge was locating each substation to have a plausible geographic position while also orienting the connecting lines at 90° or 45° (though we had to cheat in places, either by adding inflection points, or by tolerating ‘wrong’ angles) While some node-positioning algorithms were used in the early stages, the bulk of the work here was done manually, with a 45° set square perched up against the screen. Strict geographical accuracy is sacrificed where this allows a cleaner depiction of the system's connective structure. Provided as-is and without warranty.
  • Publication
    Novel Branch Centrality Measures for Electrical Power Systems Considering Both Load-serving and Circulating Currents
    (IEEE, 2020-10-01) ;
    Recent work on transmission usage charging has offered compelling new perspectives on how current flows in electrical power systems. One new insight is that a certain component of branch current flows solely to serve loads in the system, whereas another component arises because of voltage mismatches between generator buses. These circulating currents affect active power losses and branch congestion, and thus may be of renewed interest to system operators. This paper presents novel power system visualizations which better show the separate load-serving and circulating aspects of a network. A key insight that emerges is the dual role of the branches in a system: they carry both load serving and circulating currents, in heterogeneous proportions. This perspective permits new branch centrality metrics to be proposed, which separately gauge a branch’s role in serving these distinct functions.
      171Scopus© Citations 2
  • Publication
    Novel Quality Metrics for Power System Diagrams
    (IEEE, 2016-04-08) ;
    Power network diagrams are typically neither enlightening nor attractive to look at. Encouragingly, though, the visualization of generic complex networks has been an active area of research for the past two decades, and there now exist a number of widely-deployed algorithms that show a network's structure in a revealing and aesthetic way. Additionally, recent work by the present authors has proposed techniques for diagramming power systems that explicitly use meaningful electrical distance metrics. Which is the most effective approach to diagramming? To begin to answer this question, this paper proposes new quality metrics for power system diagrams which seek to quantify how legibly a network layout reveals how power flows through it.
      396Scopus© Citations 8
  • Publication
    Flexible mobility in the smart city: the role of small personal electric vehicles
    (Springer, 2018-04-12)
    A new class of personal vehicles, sometimes called ridables, has recently attained a level of technical maturity. These electric vehicle are light, portable and suitable for transporting an individual person in an urban environment. As batteries become increasingly affordable and energy dense, the range and capabilities of these vehicles are correspondingly enhanced. Notably, many ridables are suitable for intermodal commuting, as they are typically small enough to be brought along on a bus, train or tram. As such, this new class of vehicles seems to offer particular value for urban commuters, though this emerging use case has not been widely discussed in the extant literature. The present work seeks to provide a brief survey of the capabilities of the relevant vehicles, and to discuss some initial loose estimates for the portion of urban commuters for which they may be useful. Tentative suggestions for city planners and policy makers are offered to stimulate a discourse on how the capabilities of these vehicles can best be harnessed to foster sustainable and inclusive cities.
  • Publication
    Hijacking Internet-connected Devices to Provoke Harmful Oscillations in an Electrical Network: a Feasibility Assessment
    (The Institution of Engineering and Technology, 2020-07-06) ;
    Internet-connected devices will represent an increasing proportion of the load served by electric power systems. As these devices could conceivably be hijacked and controlled remotely by a malicious actor, they could represent a new threat vector against the dynamic security of a power system. Such attack strategies have not been considered in the existing literature on power system cybersecurity. As an initial scoping exercise, the present case study explores whether such devices could be remotely hijacked and then maliciously power-cycled at particular frequencies to deliberately provoke harmful oscillations in an electrical grid. To gauge the broad feasibility of this novel style of attack, dynamic simulations are performed on two representative test power systems, at differing levels of attacker and defender resources. These simulations show that power-cycling just 1% of consumer loads at a system's resonant frequency may sometimes provoke harmful electromechanical oscillations throughout a national grid. This novel simulation exercise therefore implies that cybersecurity vulnerabilities at the consumer side could jeopardise the physical integrity of a nation's entire electricity supply.
      176Scopus© Citations 1
  • Publication
    A Deterministic Approach to Locating Series Flow-Controllers Within Transmission Systems to Alleviate Congestion
    (Elsevier, 2017) ;
    This paper proposes a new technique to intelligently split busbars within a meshed power system, to facilitate the insertion of series active power flow-controllers into the high voltage transmission systems. Such flow-controllers have historically been placed at system and national boundaries to modulate cross-border flows for regulatory, commercial and security purposes. The present work proposes a new concept for power system control, and embeds series flow-controllers within meshed transmission networks to gauge the extent to which their dispatchable flows can be used to alleviate thermal congestion. To articulate the value that such flexibility might provide, a new simplified unit commitment and dispatch formulation is presented, which integrally uses series flow-controllers to manage congestion and thus reduce operating costs. While both the siting and operation methodologies are shown to be practical, the achieved cost savings are modest at best, even on systems which are weakened to have significant levels of thermal congestion.
      321Scopus© Citations 2