Intentional Controlled Islanding and Risk Assessment: A Unified Framework

Power systems are prone to cascading outages leading to large-area blackouts, and intentional controlled islanding (ICI) can mitigate these catastrophic events by splitting the system into sustainable islands. ICI schemes are used as the last resort to prevent cascading events; thus, it is critical to evaluate the corresponding system risks to ensure their correct operation. This paper proposes a unified framework to assess the risk of ICI schemes. First, a novel ICI method to create islands with minimum power imbalance is presented. Further, a risk assessment methodology is used to assess the probability and impact of the main operational modes of the ICI scheme. The unified framework provides insights on the benefits of implementing ICI, considering the uncertainties related to its reliability. The ICI scheme is demonstrated using the IEEE 9-bus system. The proposed unified framework is then fully deployed on the actual power system of Cyprus. Multiple case studies on the real network are created to demonstrate the adaptability and robustness of the proposed scheme to different system conditions. The adoption of the unified framework highlights that the system risk significantly reduces with the ICI in service, even when the reliability uncertainties associated with the scheme are considered.J. Quirós-Tortós, P. Demetriou, M. Panteli, E. Kyriakides and V. Terzija, "Intentional Controlled Islanding and Risk Assessment: A Unified Framework," IEEE Systems Journal., pp. 1-11, Oct. 2017. © 2017 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

A risk-based methodology for defining the time of intentional controlled islanding

This paper has been accepted for presentation at the IEEE/PES ISGT LA 2015, for publication in the conference proceedings and submitted for publication in the IEEE Xplore.Power systems are operated close to their stability limits and this increases the probability of cascading outages leading to large-area blackouts. To mitigate these phenomena, intentional controlled islanding (ICI) has been suggested as an effective corrective strategy that splits the system into sustainable subsystems (islands). There are two primary aspects associated with ICI: i) where to island, and ii) when to island? This work focuses on the latter and proposes a risk-based methodology that compares in a real-time fashion (i.e., quickly enough) the overall risk of the system without and with islanding (i.e., when an ICI scheme is activated) in order to define a suitable time for system splitting. Simulation results on the IEEE 9-bus system demonstrate the effectiveness of the methodology in determining a suitable time for the creation of islands, which in turn corresponds to the crossing point between the risks of the system without and with islanding.Universidad de Costa Rica. Escuela de Ingeniería EléctricaUCR::Vicerrectoría de Docencia::Ingeniería::Facultad de Ingeniería::Escuela de Ingeniería Eléctric

Interrogating China’s Global Urban Presence

This paper examines the socio-economic and geopolitical outcomes associated with infrastructure development across multiple scales. Starting from the premise that planetary socio-technical transformations in this vein have distinctly national drivers, we focus on the urban agency of Chinese-led investment. The paper explores how different forms of infrastructural development generated by the Belt and Road Initiative (BRI) affects transformations in the political and material fabric of cities and their host regions. We approach BRI-related infrastructural practice through three interconnected optics – discourse, instruments, and politics – so as to interrogate the articulation of projects linked to the BRI within the material site of the urban. Based on theorisations of infrastructure from an urban perspective and a critical review of literature on the BRI itself, we develop three illustrative case studies at different spatial scales and within different geographic contexts – in Pakistan, Central Europe and the UK. To examine the cases as well as their embeddedness in broader debates on the topic, we use a systematic review methodology relying on a wide variety of sources. We offer comparative and relational perspectives on the manner in which these relatively diverse cases demonstrate China’s role as a global urban actor