Distributed Power-Line Outage Detection Based on Wide Area Measurement System

In modern power grids, the fast and reliable detection of power-line outages is an important functionality, which prevents cascading failures and facilitates an accurate state estimation to monitor the real-time conditions of the grids. However, most of the existing approaches for outage detection suffer from two drawbacks, namely: (i) high computational complexity; and (ii) relying on a centralized means of implementation. The high computational complexity limits the practical usage of outage detection only for the case of single-line or double-line outages. Meanwhile, the centralized means of implementation raises security and privacy issues. Considering these drawbacks, the present paper proposes a distributed framework, which carries out in-network information processing and only shares estimates on boundaries with the neighboring control areas. This novel framework relies on a convex-relaxed formulation of the line outage detection problem and leverages the alternating direction method of multipliers (ADMM) for its distributed solution. The proposed framework invokes a low computational complexity, requiring only linear and simple matrix-vector operations. We also extend this framework to incorporate the sparse property of the measurement matrix and employ the LSQRalgorithm to enable a warm start, which further accelerates the algorithm. Analysis and simulation tests validate the correctness and effectiveness of the proposed approaches

A survey on the development status and application prospects of knowledge graph in smart grids

With the advent of the electric power big data era, semantic interoperability and interconnection of power data have received extensive attention. Knowledge graph technology is a new method describing the complex relationships between concepts and entities in the objective world, which is widely concerned because of its robust knowledge inference ability. Especially with the proliferation of measurement devices and exponential growth of electric power data empowers, electric power knowledge graph provides new opportunities to solve the contradictions between the massive power resources and the continuously increasing demands for intelligent applications. In an attempt to fulfil the potential of knowledge graph and deal with the various challenges faced, as well as to obtain insights to achieve business applications of smart grids, this work first presents a holistic study of knowledge-driven intelligent application integration. Specifically, a detailed overview of electric power knowledge mining is provided. Then, the overview of the knowledge graph in smart grids is introduced. Moreover, the architecture of the big knowledge graph platform for smart grids and critical technologies are described. Furthermore, this paper comprehensively elaborates on the application prospects leveraged by knowledge graph oriented to smart grids, power consumer service, decision-making in dispatching, and operation and maintenance of power equipment. Finally, issues and challenges are summarised.Comment: IET Generation, Transmission & Distributio

Identifying Appliances using NIALM with Minimum Features

Government of India has decided to install smart meters in fourteen states. Smart meters are required to identify home appliances to fulfill various tasks in the smart grid environment. Both intrusive and non-intrusive methods have been suggested for identification. However, intrusive method is not suitable for cost and privacy reasons. On the other hand, techniques using non-intrusive appliance load monitoring (NIALM) are yet to result in meaningful practical implementation. Two major challenges in NIALM research are the choice of features (load signatures of appliances), and the appropriate algorithm. Both have a direct impact on the cost of the smart meter. In this paper, we address the two issues and propose a procedure with only four features and a simple algorithm to identify appliances. Our experimental setup, on the recommended specifications of the internal electrical wiring in Indian residences, used common household appliances’ load signatures of active and reactive powers, harmonic components and their magnitudes. We show that these four features are essential and sufficient for implementation of NIALM with a simple algorithm. We have introduced a new approach of ‘multi point sensing’ and ‘group control’ rather than the ‘single point sensing’ and ‘individual control’, used so far in NIALM techniques.DOI:http://dx.doi.org/10.11591/ijece.v4i6.671

In-situ Data Analytics In Cyber-Physical Systems

Cyber-Physical System (CPS) is an engineered system in which sensing, networking, and computing are tightly coupled with the control of the physical entities. To enable security, scalability and resiliency, new data analytics methodologies are required for computing, monitoring and optimization in CPS. This work investigates the data analytics related challenges in CPS through two study cases: Smart Grid and Seismic Imaging System. For smart grid, this work provides a complete solution for system management based on novel in-situ data analytics designs. We first propose methodologies for two important tasks of power system monitoring: grid topology change and power-line outage detection. To address the issue of low measurement redundancy in topology identification, particularly in the low-level distribution network, we develop a maximum a posterior based mechanism, which is capable of embedding prior information on the breakers status to enhance the identification accuracy. In power-line outage detection, existing approaches suer from high computational complexity and security issues raised from centralized implementation. Instead, this work presents a distributed data analytics framework, which carries out in-network processing and invokes low computational complexity, requiring only simple matrix-vector multiplications. To complete the system functionality, we also propose a new power grid restoration strategy involving data analytics for topology reconfiguration and resource planning after faults or changes. In seismic imaging system, we develop several innovative in-situ seismic imaging schemes in which each sensor node computes the tomography based on its partial information and through gossip with local neighbors. The seismic data are generated in a distributed fashion originally. Dierent from the conventional approach involving data collection and then processing in order, our proposed in-situ data computing methodology is much more ecient. The underlying mechanisms avoid the bottleneck problem on bandwidth since all the data are processed distributed in nature and only limited decisional information is communicated. Furthermore, the proposed algorithms can deliver quicker insights than the state-of-arts in seismic imaging. Hence they are more promising solutions for real-time in-situ data analytics, which is highly demanded in disaster monitoring related applications. Through extensive experiments, we demonstrate that the proposed data computing methods are able to achieve near-optimal high quality seismic tomography, retain low communication cost, and provide real-time seismic data analytics

GNSS Related Threats to Power Grid Applications

As power grid environments are moving towards the smart grid vision of the future, the traditional schemes for power grid protection and control are making way for new applications. The advancements in this field have made the requirements for power grid’s time synchronization accuracy and precision considerably more demanding. So far, the signals provided by Global Navigation Satellite Systems have generally addressed the need for highly accurate and stable reference time in power grid applications. These signals however are highly susceptible to tampering as they are being transmitted. Since electrical power transmission and distribution are critical functions for any modern society, the risks and impacts affiliated with satellite-based time synchronization in power grids ought to be examined. This thesis aims to address the matter. The objective is to examine how Global Navigation Satellite Systems are utilized in the power grids, how different attacks would potentially be carried out by employing interference and disturbance to GNSS signals and receivers and how the potential threats can be mitigated. A major part of the research is done through literature review, and the core concepts and different implementations of Global Navigation Satellite Systems are firstly introduced. The literature review also involves the introduction of different power grid components and subsystems, that utilize Global Positioning System for time synchronization. Threat modeling techniques traditionally practiced in software development are applied to power grid components and subsystems to gain insight about the possible threats and their impacts. The threats recognized through this process are evaluated and potential techniques for mitigating the most notable threats are presented.Sähköverkot ovat siirtymässä kohti tulevaisuuden älykkäitä sähköverkkoja ja perinteiset sähköverkon suojaus- ja ohjausmenetelmät tekevät tilaa uusille sovelluksille. Alan kehitys on tehnyt aikasynkronoinnin tarkkuusvaatimuksista huomattavasti aikaisempaa vaativampia. Tarkka aikareferenssi sähköverkoissa on tähän saakka saavutettu satelliittinavigointijärjestelmien tarjoamien signaalien avulla. Nämä signaalit ovat kuitenkin erittäin alttiita erilaisille hyökkäyksille. Sähkönjakelujärjestelmät ovat kriittinen osa nykyaikaista yhteiskuntaa ja riskejä sekä seuraamuksia, jotka liittyvät satelliittipohjaisten aikasynkronointimenetelmien hyödyntämiseen sähköverkoissa, tulisi tarkastella. Tämä tutkielma pyrkii vastaamaan tähän tarpeeseen. Päämääränä on selvittää, miten satelliittinavigointijärjestelmiä hyödynnetään sähköverkoissa, kuinka erilaisia hyökkäyksiä voidaan toteuttaa satelliittisignaaleja häiritsemällä ja satelliittisignaalivastaanottimia harhauttamalla ja kuinka näiden muodostamia uhkia voidaan lieventää. Valtaosa tästä tutkimuksesta on toteutettu kirjallisuuskatselmoinnin pohjalta. Työ kattaa satelliittinavigointijärjestelmien perusteet ja esittelee erilaisia tapoja, kuinka satelliittisignaaleja hyödynnetään sähköverkoissa erityisesti aikasynkronoinnin näkökulmasta. Työssä hyödynnettiin perinteisesti ohjelmistokehityksessä käytettyjä uhkamallinnusmenetelmiä mahdollisten uhkien ja seurausten analysointiin. Lopputuloksena esitellään riskiarviot uhkamallinnuksen pohjalta tunnistetuista uhkista, sekä esitellään erilaisia menettelytapoja uhkien lieventämiseksi

Microgrids for Micro-Communities: Reducing the Energy Burden in Rural Areas

Rural communities currently face some of the highest energy costs and lowest reliability in the country, due in part to long transmission distances and low population densities. The North American Supergrid (“NAS”) has been proposed as a solution for increased grid stability, resiliency, and renewable generation with decreased carbon emissions and energy cost across the lower 48 states. Although the NAS could help with these energy goals, it is likely that benefits of the NAS would bypass many rural or isolated communities outside of the transmission step-down points. As the NAS will not help rural communities, states can take regulatory action aimed at promoting microgrid systems of locally generated renewable energy. Remote communities in Alaska have already taken advantage of microgrid systems, and Alaska’s microgrid policies could serve as a model for rural communities in the lower 48. This Note proposes regulatory changes to states’ microgrid policies, based on Alaska’s policies, to bolster renewable generation based microgrid system development for rural communities by (1) identifying and clearly defining important factors affecting microgrid implementation, (2) setting high renewable portfolio standards, (3) increasing financial investment, and (4) collaborating with other states and interest groups to share information. By considering Alaska’s policies as a prototype, states across the country can increase rural residents’ access to affordable energy

Novel processes for smart grid information exchange and knowledge representation using the IEC common information model

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The IEC Common Information Model (CIM) is of central importance in enabling smart grid interoperability. Its continual development aims to meet the needs of the smart grid for semantic understanding and knowledge representation for a widening domain of resources and processes. With smart grid evolution the importance of information and data management has become an increasingly pressing issue not only because far more data is being generated using modern sensing, control and measuring devices but also because information is now becoming recognised as the ‘integral component’ that facilitates the optimal flexibility required of the smart grid. This thesis looks at the impacts of CIM implementation upon the landscape of smart grid issues and presents research from within National Grid contributing to three key areas in support of further CIM deployment. Taking the issue of Enterprise Information Management first, an information management framework is presented for CIM deployment at National Grid. Following this the development and demonstration of a novel secure cloud computing platform to handle such information is described. Power system application (PSA) models of the grid are partial knowledge representations of a shared reality. To develop the completeness of our understanding of this reality it is necessary to combine these representations. The second research contribution reports on a novel methodology for a CIM-based model repository to align PSA representations and provide a knowledge resource for building utility business intelligence of the grid. The third contribution addresses the need for greater integration of information relating to energy storage, an essential aspect of smart energy management. It presents the strategic rationale for integrated energy modeling and a novel extension to the existing CIM standards for modeling grid-scale energy storage. Significantly, this work has already contributed to a larger body of work on modeling Distributed Energy Resources currently under development at the Electric Power Research Institute (EPRI) in the USA.Dr. Martin Bradley on behalf of National Grid Plc. and the Engineering and Physical Sciences Research Council (EPSRC

Performing Continuity of/in Smart Infrastructure : Exploring Entanglements of Infrastructure and Actions

Nearly everything we do in contemporary organizations and societies builds on some form of infrastructure. Our reliance on infrastructures underscores the importance of the continuity of these infrastructures. However, the infrastructures are inherently unreliable and unpredictable and achieve veneers of permanence and stability only through constant and ongoing efforts. In their functioning, they become established through complex and uncertain processes that involve a number of actors and factors. Consequently, understanding those processes is a key concern for organizations that are responsible for these infrastructures. Traditionally, the literature on the business continuity of organizational functions has emphasized the importance of planning and management approaches. Practitioners and academics have brought forth frameworks to aid organizations in planning and managing their continuity-related issues. The frameworks offer universally applicable processes and procedures that organizations should follow to improve their continuity. However, these frameworks tell little about continuity itself. Organizations rarely function as they document or as management describes organizational work. As such, the complex and uncertain processes of continuity cannot be directly inferred from the documents or from the managerial descriptions of work. If we wish to enact meaningful changes to those complex and uncertain processes through which infrastructure continuity becomes established, we need to understand how those processes unfold in practice. This dissertation focuses on infrastructure continuity in a smart infrastructure context. Smart infrastructures are traditional infrastructures that have been extended with digital technologies. In this research, infrastructure continuity is approached from the perspective of technicians working in the smart infrastructure context. The technicians’ work in these contexts is constitutively entangled with information systems and the technologies that form the infrastructures. As such, the smart infrastructures form an intriguing and fruitful yet rather unexplored context for information systems research. Theoretically, this research builds on sociomaterial theorizing and especially on Karen Barad’s agential realism. The purpose of this dissertation is to increase understanding on how the continuity of smart infrastructure becomes performed. This purpose is explored through six research articles that form the foundations of this dissertation. Methodologically, this research builds on conceptual and empirical research approaches. The conceptual research focuses on developing and clarifying business continuity- and sociomateriality-related concepts and approaches through argumentation and a literature review. The empirical research builds on a qualitative research approach and, more specifically, on ethnographic research. As is typical for ethnographic research, the empirical material was collected from a single organization that was studied extensively over a several-month participant observation. Reflecting the purpose of the study, the ethnography was conducted in a centralized operations center of a smart infrastructure (smart power grid) where technicians work with information systems and technologies. This dissertation contributes to the literature on infrastructure continuity and on sociomateriality. The primary contribution to the infrastructure continuity literature is a performative conceptualization of the infrastructure continuity. This conceptualization suggests that business continuity is not an attribute of any single measure but is an outcome of a joint accomplishment of sociomaterial networks of agencies that becomes established through recurrent actions. As such, the findings of this research challenge some of the taken-for-granted assumptions embedded in the literature but also extend the earlier literature. In addition, this dissertation extends discussions on sociomaterial agency. In the light of the findings, when agency is situated in the context of a smart infrastructure, agency becomes historic, polycentric, dynamic, and discontinuous.Lähes kaikki mitä me teemme nyky-yhteiskunnassa nojaa infrastruktuureihin. Voimmekin sanoa elävämme keskellä infrastruktuurien verkostoa. Riippuvaisuutemme infrastruktuureista korostaa niiden toiminnan jatkuvuuden tärkeyttä. Nämä infrastruktuurit ovat kuitenkin perustaltaan epäluotettavia ja arvaamattomia. Niiden toimivuus syntyy monimutkaisten ja epävarmojen prosessien kautta, jotka sisältävät moninaisia toimijoita ja tekijöitä. Näiden prosessien ymmärtäminen on keskeistä organisaatioille, jotka vastaavat näistä infrastruktuureista. Perinteisesti kirjallisuudessa, joka keskittyy toiminnan jatkuvuuteen (eng. business continuity), on korostettu suunnitelmien ja hallinnoinnin merkitystä. Suunnitteluun ja hallinnointiin on kehitetty useita johtamisen viitekehyksiä. Ne tarjoavat universaaleiksi tarkoitettuja määrämuotoisia prosesseja ja menettelytapoja, joita organisaatioiden tulisi noudattaa. Nämä viitekehykset kertovat kuitenkin hyvin vähän siitä mitä tai miten toiminnan jatkuvuus itsessään käytännössä ilmenee. Organisaatiot harvoin toimivat kuten dokumentoivat tai kuten organisaatioiden johto kuvailee toimintaa, joten näistä ei voida suoraan päätellä organisaation toimintaa. Kuitenkin jos haluamme toteuttaa merkityksellisiä muutoksia niihin monimutkaisiin ja epävarmoihin prosesseihin, joiden kautta toiminnan jatkuvuus syntyy, meidän tulee ymmärtää paremmin näitä prosesseja käytännössä. Tässä tietojärjestelmätieteisiin sijoittuvassa väitöskirjassa keskitytään toiminnan jatkuvuuteen älykkäiden infrastruktuurien (eng. smart infrastructure) kontekstissa. Älykkäillä infrastruktuureilla tarkoitetaan tässä tutkimuksessa perinteisiä infrastruktuureja, kuten sähköverkkoja, vedenjakelua, ja tieverkostoa, jotka ovat digitalisoitu. Aihetta lähestytään erityisesti infrastruktuurin parissa toimivien teknikoiden työn kautta. Teknikoiden työ näissä ympäristöissä on nivoutunut kiinteästi yhteen tietojärjestelmien ja teknologioiden kanssa, jotka muodostavat infrastruktuurin. Älykkäät infrastruktuurit muodostavatkin näin erityisesti tietojärjestelmätieteiden tutkimukselle kiinnostavan, mutta vähän tutkitun kontekstin. Tutkimus pohjautuu teoreettisesti sosiomateriaalisuuteen ja nojaa erityisesti Karen Baradin filosofiseen ja teoreettiseen viitekehykseen toimijarealismista (eng. agential realism). Tutkimuksen tavoite on tuottaa ymmärrystä siitä, miten infrastruktuurien jatkuvuus toteutuu käytännössä. Tätä tavoitetta on tässä väitöskirjassa tutkittu kuuden vertaisarvioidun artikkelin kautta. Menetelmällisesti tutkimuksessa on nojattu sekä konseptuaaliseen että empiiriseen tutkimukseen. Konseptuaalinen tutkimus keskittyy toiminnan jatkuvuuden ja sosiomateriaalisuuden käsitteiden ja lähestymistapojen kehittämiseen sekä selventämiseen argumentoinnin ja kirjallisuuskatsauksen avulla. Empiirinen tutkimuspohjautuu laadulliseen tutkimusotteeseen ja nojaa etnografiseen tutkimusmenetelmään. Kuten etnografiselle tutkimusmenetelmälle on luonnollista, aineisto pohjautuu pääosin osallistuvaan havainnointiin yhdessä organisaatiossa, jota on tutkittu intensiivisesti. Heijastaen tutkimuksen tavoitetta ja ongelmanasettelua, etnografinen tutkimus suoritettiin älykkään infrastruktuurin (sähköverkon) keskitetyssä valvomossa, jossa teknikoiden työtä tietojärjestelmien ja teknologioiden parissa seurattiin useiden kuukausien ajan. Tutkimuksen tulokset osallistuvat infrastruktuurien toiminnan jatkuvuuden ja sosiomaterialisuuden keskusteluihin. Tutkimuksen keskeisin tulos toiminnan jatkuvuuden tutkimukseen on toiminnan jatkuvuuden konseptualisointi suoritettuna toimintana. Tämän konseptualisoinnin mukaan toiminnan jatkuvuus ei ole jonkin menetelmän ominaisuus vaan jatkuvuus tuotetaan yhteisesti sosiomateriaalisessa toimijoiden verkossa toistuvien tekojen kautta. Tutkimuksen tulokset siis haastavat mutta myös edistävät aiempaa kirjallisuutta toiminnan jatkuvuudesta. Lisäksi, tutkimuksen tulokset edistävät keskusteluita toimijuuden sosiomateriaalisuudesta. Tulosten valossa, kun toimijuutta tarkastellaan infrastruktuurikontekstissa, on toimijuus historiallinen, polysentrinen, dynaaminen ja yllätyksellinen.Siirretty Doriast