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

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Can Distribution Grids Significantly Contribute to Transmission Grids' Voltage Management?

Power generation in Germany is currently transitioning from a system based on large, central, thermal power plants to one that heavily relies on small, decentral, mostly renewable power generators. This development poses the question how transmission grids' reactive power demand for voltage management, covered by central power plants today, can be supplied in the future. In this work, we estimate the future technical potential of such an approach for the whole of Germany. For a 100% renewable electricity scenario we set the possible reactive power supply in comparison with the reactive power requirements that are needed to realize the simulated future transmission grid power flows. Since an exact calculation of distribution grids' reactive power potential is difficult due to the unavailability of detailed grid models on such scale, we optimistically estimate the potential by assuming a scaled, averaged distribution grid model connected to each of the transmission grid nodes. We find that for all except a few transmission grid nodes, the required reactive power can be fully supplied from the modeled distribution grids. This implies that - even if our estimate is overly optimistic - distributed reactive power provisioning will be a technical solution for many future reactive power challenges

Network Services from Distributed Solar PV and Inverters

Networks Renewed is a major new project funded by the Australian Renewable Energy Agency (ARENA) that aims to demonstrate how solar PV, battery storage and inverters can support distribution networks in managing power quality. The path to implementation will be established by two commercial-scale demonstrations of controlled solar PV and energy storage in the regional Mid North Coast of NSW, and suburban Melbourne in Victoria. At the time of this conference the deployment of inverters and control technologies will have commenced towards pilot-scale demonstrations to test candidate control algorithms, several of which have been published in the engineering literature. These will develop into market-scale demonstrations to achieve useful power quality improvements on selected network segments, and also market trading revenues, should these materially improve the financial returns to customers from inverter control

An adaptive overcurrent protection scheme for distribution networks

Distribution networks are evolving toward the vision of smart grids, with increasing penetration of distributed generation (DG), introduction of active network management (ANM), and potentially islanded modes of operation. These changes affect fault levels and fault current paths and have been demonstrated to compromise the correct operation of the overcurrent protection system. This paper presents an adaptive overcurrent protection system which automatically amends the protection settings of all overcurrent relays in response to the impact of DG, ANM, and islanding operation. The scheme has been developed using commercially available protection devices, employs IEC61850-based communications, and has been demonstrated and tested using a hardware-in-the-loop laboratory facility. A systematic comparison of the performance of the proposed adaptive scheme alongside that of a conventional overcurrent scheme is presented. This comparison quantifies the decrease in false operations and the reduction of mean operating time that the adaptive system offers

PRZEGLĄD METOD REGULACJI NAPIĘCIA W SIECIACH ELEKTROENERGETYCZNYCH NISKIEGO NAPIĘCIA Z DUŻYM UDZIAŁEM GENERACJI ROZPROSZONEJ

Deterioration of voltage conditions is one of the frequent consequences of connecting an increasing number of photovoltaic sources to the low-voltage (LV) power grid. Under adverse conditions, i.e. low energy consumption and high insolation, microgeneration can cause voltage surges that violate acceptable limits. Research shows that the increase in voltage is the main limitation for connecting new energy microsources to the LV network and forces the reconstruction of the network. An alternative to costly modernizations can be the implementation of appropriate strategies for controlling network operation to maintain the voltage at the required level. The article presents an overview of the methods and concepts of voltage control in a low-voltage network developed so far to mitigate the undesirable phenomenon of voltage boosting. The focus was mainly on local methods—not requiring communication infrastructure—as best suited to the conditions of Polish distribution networks. Gathering the results of many tests and simulations carried out in different conditions and on different models allowed for the formulation of general conclusions and can be a starting point for further research on a control method that can be widely used in the national power system.Jedną z częstych konsekwencji przyłączania do sieci elektroenergetycznej niskiego napięcia (nn) coraz większej liczby źródeł fotowoltaicznych jest pogorszenie warunków napięciowych. W niesprzyjających warunkach – przy niskim poborze energii i wysokim nasłonecznieniu – mikrogeneracja może powodować podskoki napięcia przekraczające dopuszczalne granice. Badania pokazują, że wzrost napięcia stanowi podstawowe ograniczenie dla przyłączania nowych mikroźródeł energii do sieci nn i wymusza przebudowę sieci. Alternatywą dla kosztownych modernizacji może być wdrożenie odpowiednich strategii sterowania pracą sieci pozwalających utrzymać napięcie na wymaganym poziomie. W artykule zaprezentowano przegląd opracowanych dotychczas metod i koncepcji regulacji napięcia w sieci nn mających na celu opanowanie niepożądanego zjawiska podbicia napięcia. Skupiono się głównie na metodach lokalnych – nie wymagających do prawidłowego działania infrastruktury komunikacyjnej – jako najlepiej przystosowanych do warunków polskich sieci dystrybucyjnych. Zebranie wyników badań i symulacji, przeprowadzonych przy różnych założeniach i na różnych modelach, pozwoliło na sformułowanie ogólnych wniosków i może stanowić punkt wyjścia do dalszych badań nad metodą sterowania mogącą znaleźć szerokie zastosowanie w krajowym systemie elektroenergetycznym

Modelling, evaluation and demonstration of novel active voltage control schemes to accomodate distributed generation in distribution networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Voltage control in distribution networks is becoming more challenging due to the growing amount of distributed generation that is being connected to the distribution networks in addition to increasing load. The output of the distributed generation can radically change power flows and voltage profiles in distribution networks, creating conditions that adversely affect the performance of automatic voltage control schemes and in addition cause unacceptable voltage rise. On the other hand, inherent limitations and current operational policies of AVC schemes very often restrict the output of DG or even prevent its connection. This thesis investigates and analyses voltage control in terms of the shift from passive to active distribution networks. The thesis also reviews the performance of AVC schemes under varying load and generation output conditions, investigates effective utilisation of distribution network assets and methods to accommodate active voltage control schemes into existing infrastructure. A range of active voltage control and management schemes based on coordinated voltage control is presented and assessed. These schemes can be used to improve the voltage profile in distribution networks and increase their ability to accommodate distributed generation. The functionality of each scheme is assessed based on a number of factors such as the ability of the scheme to increase network capacity, reliability and accuracy. Simulation software to accurately evaluate the performance of an active voltage control scheme in a particular distribution network scenario is essential before the scheme can be deployed. Formal assessment of advanced AVC models and SuperTAPP n+ functionality is performed using simulation software as developed and presented in this thesis. The accuracy of the software results and performance of the SuperTAPP n+ scheme is validated based on network trials carried out in EDF Energy Networks.This work is funded by the Engineering and Physical Sciences Research Council (EPSRC) and EDF Energy Networks