Impact Assessment of Hypothesized Cyberattacks on Interconnected Bulk Power Systems

The first-ever Ukraine cyberattack on power grid has proven its devastation by hacking into their critical cyber assets. With administrative privileges accessing substation networks/local control centers, one intelligent way of coordinated cyberattacks is to execute a series of disruptive switching executions on multiple substations using compromised supervisory control and data acquisition (SCADA) systems. These actions can cause significant impacts to an interconnected power grid. Unlike the previous power blackouts, such high-impact initiating events can aggravate operating conditions, initiating instability that may lead to system-wide cascading failure. A systemic evaluation of "nightmare" scenarios is highly desirable for asset owners to manage and prioritize the maintenance and investment in protecting their cyberinfrastructure. This survey paper is a conceptual expansion of real-time monitoring, anomaly detection, impact analyses, and mitigation (RAIM) framework that emphasizes on the resulting impacts, both on steady-state and dynamic aspects of power system stability. Hypothetically, we associate the combinatorial analyses of steady state on substations/components outages and dynamics of the sequential switching orders as part of the permutation. The expanded framework includes (1) critical/noncritical combination verification, (2) cascade confirmation, and (3) combination re-evaluation. This paper ends with a discussion of the open issues for metrics and future design pertaining the impact quantification of cyber-related contingencies

System development issues concerning integration of wind generation in Great Britain

The European Union has committed itself to sourcing 20% of its energy from renewables by 2020. Britain's excellent wind resource is expected to make a significant contribution to this target, not least from Scotland and the north of England. However, exploitation of this resource requires appropriate and timely development of the GB electricity transmission system. This depends on appropriate market signals that communicate the need for transmission investment, something that many in the industry in Britain believe current arrangements do not adequately provide. This paper describes a number of proposals currently under discussion, outlines their interactions and highlights some of the key issues currently being debated

Analysis of significant factors on cable failure using the Cox proportional hazard model

This paper proposes the use of the Cox proportional hazard model (Cox PHM), a statistical model, for the analysis of early-failure data associated with power cables. The Cox PHM analyses simultaneously a set of covariates and identifies those which have significant effects on the cable failures. In order to demonstrate the appropriateness of the model, relevant historical failure data related to medium voltage (MV, rated at 10 kV) distribution cables and High Voltage (HV, 110 kV and 220 kV) transmission cables have been collected from a regional electricity company in China. Results prove that the model is more robust than the Weibull distribution, in that failure data does not have to be homogeneous. Results also demonstrate that the method can single out a case of poor manufacturing quality with a particular cable joint provider by using a statistical hypothesis test. The proposed approach can potentially help to resolve any legal dispute that may arise between a manufacturer and a network operator, in addition to providing guidance for improving future practice in cable procurement, design, installations and maintenance

Pendekatan psikologi dakwah menangani histeria remaja muslim di Selangor

Gejala histeria dalam kalangan remaja di Malaysia merupakan epidemik sosial yang telah lama berlaku dalam masyarakat. Kejadian tersebut mengganggu proses pengajaran dan pembelajaran, psikologi, jasmani dan spiritual remaja. Pelbagai pendekatan pencegahan dilakukan oleh remaja dan pihak sekolah dalam menangani gejala yang berlaku, namun tidak menunjukkan pengurangannya. Oleh itu kajian ini bertujuan mengenal pasti konsep histeria, menganalisis faktor dan simptom histeria remaja, mengenal pasti pendekatan psikologi dakwah untuk menangani histeria, mengkaji kaedah pencegahan yang dilakukan remaja terhadap gejala histeria serta menganalisis hubungan antara faktor, simptom dan langkah pencegahan. Reka bentuk kajian adalah kajian tinjauan dengan menggunakan instrumen soal selidik dan temu bual. Seramai 122 orang responden yang mengalami histeria dari 10 buah sekolah di Selangor dipilih secara persampelan kelompok dan seramai 9 orang pelajar yang mengalami histeria ditemu bual. Temu bual turut dijalankan terhadap kaunselor, pakar psikiatri dan perawat perubatan Islam bagi menyokong dapatan kajian. Hasil kajian mendapati terdapat lima faktor histeria dalam kalangan remaja Muslim iaitu faktor psikologi, tekanan keluarga dan persekitaran, kepercayaan dan kebudayaan dan amalan keagamaan. Manakala dari aspek simptom, terdapat tiga bentuk simptom iaitu simptom gangguan emosi, psikiatri dan gangguan makhluk halus. Dari sudut pencegahan, remaja yang mengalami histeria kerap menggunakan pencegahan secara tazkiyah al-nafs, perawatan Islam dan psikiatri. Hasil analisis hubungan antara faktor dan simptom histeria mendapati faktor yang berhubung secara signifikan dengan ketiga-tiga simptom histeria adalah faktor psikologi, tekanan persekitaran dan kepercayaan dan kebudayaan. Manakala dari aspek pencegahan terdapat hubungan yang signifikan antara pencegahan tazkiyah al-nafs dan perawatan Islam dengan simptom gangguan emosi. Implikasi kajian dapat membantu pelbagai pihak dalam menangani punca dan simptom histeria remaja dengan menggunakan pendekatan psikologi 3 dakwah

Comprehensive Overview on HVDC Converter Transformer Design: Additional Discussions to the IEC/IEEE 60076-57-129 Standard

HVDC has been chosen as an economical and technical solution for power transmission through long distances, asynchronous interconnections and long submarine cables crossing. Despite DC transmission benefits to power systems, the converters non-linearity produces undesirable effects to the converter transformer in service, mainly listed in the technical standard IEC/IEEE 60076-57-129. However, additional discussions and complementary information can be found in a plurality of references, which are brought in the article under a comprehensive overview perspective. Some design solutions deal with these effects increasing the technical margins, which have direct influence on manufacturing costs and transformer reliability and availability levels. This article goes through the main topics pointed by the standard and the references, investigating their consequences in the converter transformer operation, in order to provide a comprehensive tutorial on design solutions and considerations to deal with those undesirable effects

Review of dynamic line rating systems for wind power integration

When a wind power system is connected to a network point there is a limit of power generation based on the characteristics of the network and the loads connected to it. Traditionally, transmission line limits are estimated conservatively assuming unfavourable weather conditions (high ambient temperature, full sun and low wind speed). However, the transmission capacity of an overhead line increases when wind speed is high, due to the cooling caused by wind in the distribution lines. Dynamic line rating (DLR) systems allow monitoring real weather conditions and calculating the real capacity of lines. Thus, when planning wind power integration, if dynamic line limits are considered instead of the conservative and static limits, estimated capacity increases. This article reviews all technologies developed for real-time monitoring during the last thirty years, as well as some case studies around the world, and brings out the benefits and technical limitations of employing dynamic line rating on overhead lines. Further, the use of these DLR systems in wind integration is reviewed.This work is financially supported by the Ministerio de Economía y Competitividad under the project DPI2013-44502-R and the Eusko Jaurlaritza under the project SAI12/103

Modular multilevel converter losses model for HVdc applications

Multi-terminal high voltage dc (HVdc) grids can eventually became a feasible solution to transport energy to remote and/ or distant areas and its exploitation depend, among other things, on the performance of the converter terminals. Therefore, to optimize the power transmission strategy along such a grid, it is necessary to recognize the efficiency of all the converters in all points of operation, namely with the different load conditions. In this vision, the aim of this work is to provide the methodology to model the modular multilevel converter (MMC) efficiency by means of a mathematical expression that can describe, over a broad range of active and reactive power flow combinations, the power losses generated by the semiconductors. According to the presented methodology, a polynomial-based model with a reduced number of coefficients is deducted, in such a way that can be directly used for optimal power flow (OPF) studies. The accuracy of the proposed model is characterized by an absolute relative error, at the worst scenario, approximately equal to 3%.Postprint (author's final draft

Dielectric, Switching and System Requirements under Out-of-Phase Conditions, during Synchronisation and under Comparable Stresses

Recent developments in electrical networks can increase the probability of out-of-phase switching and dielectric stresses being applied to open circuit-breakers, due to asynchronous systems at both sides. This report presents a systematic study of TRV-stresses associated with generator separation and system separation. TRV peak values are higher than required in the Standards, even for relatively small out-of-phase angles (75º to 90º), and the dielectric stresses are high with respect to the shortduration power frequency withstand voltages across a circuit-breaker open contacts, especially taking into consideration the external insulation under pollution and ageing processes. To the opinion of the authors, the Standards should be revised to give users clear and adequate guidance on the assessment and specification of TRV-values and dielectric withstand requirements under out-of-phase conditions

New generation types in Europe versus Future Power Quality Needs

This paper aims to give an overview on main PQ development in Europe. It focuses basically on recent legislative, regulatory, standardization, voltage quality monitoring and education initiatives summarizing the latest outcomes