1,813 research outputs found

    Adaptive overcurrent protection application for a micro-grid system in South Africa

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    Abstract: The non-directional overcurrent protection (International Electrotechnical Commission standard IEC 617 or American National Standards Institute ANSI/Institute of Electrical and Electronic Engineers IEEE C37.2 standard device number 51) is one protection type/relay function that has stood the test of time. The latest generation of relays has brought about enhanced capabilities. The most popular overcurrent protection, which is the Inverse Definite Minimum Time (IDMT) function, has proven to provide coordination of electrical nodes with ease. This is one of the oldest but extremely reliable relay characteristic. A number of new protection functions and enhancements to existing functions are commensurate to the advanced technical capabilities of the newer generation protective devices. The new development techniques include “acceleration”, which is a technique of sending the circuit breaker status of the near end of a line or feeder to the far end to influence the relay decision at the far end. Impedance protection, unit line protection, etc. have come with many advanced characteristics and properties. The enhancements to protection devices bear special features but cannot substitute inverse time overcurrent protection, which, up to now, is a reliable backup in feeder protection schemes in South Africa. The superior feature is the capability to achieve coordination between a series of protective devices. This is achievable without excessive damage to the electrical components of the circuit...M.Ing. (Electrical Engineering

    Smart Grid for the Smart City

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    Modern cities are embracing cutting-edge technologies to improve the services they offer to the citizens from traffic control to the reduction of greenhouse gases and energy provisioning. In this chapter, we look at the energy sector advocating how Information and Communication Technologies (ICT) and signal processing techniques can be integrated into next generation power grids for an increased effectiveness in terms of: electrical stability, distribution, improved communication security, energy production, and utilization. In particular, we deliberate about the use of these techniques within new demand response paradigms, where communities of prosumers (e.g., households, generating part of their electricity consumption) contribute to the satisfaction of the energy demand through load balancing and peak shaving. Our discussion also covers the use of big data analytics for demand response and serious games as a tool to promote energy-efficient behaviors from end users

    Fault Location, Isolation and Network Restoration as a Self-Healing function

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    One of the main emphasis of the smart grid is the interaction of power supply and power customer in order to provide a reliable supply of power as well as to improve the flexibility of the network. Along with this, the increased energy demand, coupled with strict regulations on the quality and reliability of supply intensifies the pressure on distribution network operators to maintain the integrity of the network in its faultless operation mode. Additionally, regardless of the huge investments already made in replacing aging infrastructure and translating “the old-fashioned grid” in a “Smart Grid” to minimize the probability for equipment failure, the chances of failure cannot be completely eliminated. In accordance, in the event of faults in the network, apart from the high penalty costs in which network operators may incur, certain safety factors must be taken into consideration for particular customers (for example, hospitals). In view of that, there is a necessity to minimize the impact on customers without supply and maintain outages times as brief as possible. Within this scenario comes the concept of self-healing grid as one of the key-technologies in the smart grid environment which is partly due to the rapid development of distribution automation. Self-healing refers to the capacity of the smart grid to restore efficiently and automatically power after an outage. Self-healing main goals comprise supply maximum load affected by the fault, take the shortest time period possible for restoration of the load, minimizing the number of switching operations and keeping the network capacity within its operating limits. This research has explored insights into the smart grid in terms of the self-healing functionality within the distribution network with main emphasis on self-healing implementation types and its applicability. Initially a detailed review of the conception of the smart grid in order to integrate the self-healing and thus fault location, isolation and service restoration capabilities was conducted. This was complemented with a detailed discussion about the electricity distribution system automatic fault management in order to create a framework around which the aim of the research is based. Finally the self-healing problem coupled with current practical implementation cases was addressed with the objective of exploring the means of improvement and evolution in the automation level in the distribution network using Fault Location Isolation and Service Restoration (FLISR) applicability as a medium

    Security Issues and Challenges for the IoT-based Smart Grid

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    AbstractInternet of Things (IoT) is the next step evolution of our today Internet, where any physical object/thing having/equipped with computation and communication capabilities could be seamlessly integrated, at different levels, to the Internet. The Smart Grid (SG), which is considered as one of the most critical Infrastructures, is defined as the classical power grid augmented with a large-scale ICT and renewable energy integration, can be seen as one of the largest IoT network. The SG will involve billions of smart objects/things: smart meters, smart appliances, sensors, actuators-cars, etc. in addition to several communication infrastructures whether public (most often) or private. However, security is seen as one of the major factors hampering the rapid and large scale adoption and deployment of both the IoT vision and the Smart Grid.In this paper we investigate the security issues and challenges on the IoT-based SG, and define the major security services that we should consider when dealing with SG securit

    Threat Scenarios and Monitoring Requirements for Cyber-Physical Systems of Flexibility Markets

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    The ongoing integration of renewable generation and distributed energy resources introduces new challenges to distribution network operation. Due to the increasing volatility and uncertainty, distribution system operators (DSOs) are seeking concepts to enable more active management and control. Flexibility markets (FMs) offer a platform for economically efficient trading of electricity flexibility between DSOs and other participants. The integration of cyber, physical and market domains of multiple participants makes FMs a system of cyber-physical systems (CPSs). While cross-domain integration sets the foundation for efficient deployment of flexibility, it introduces new physical and cyber vulnerabilities to participants. This work systematically formulates threat scenarios for the CPSs of FMs, revealing several remaining security challenges across all domains. Based on the threat scenarios, unresolved monitoring requirements for secure participation of DSOs in FMs are identified, providing the basis for future works that address these gaps with new technical concepts.Comment: Published in the proceedings of the 2022 IEEE PES Generation, Transmission and Distribution Conference and Exposition - Latin America (IEEE PES GTD Latin America

    Immune System Based Control and Intelligent Agent Design for Power System Applications

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    The National Academy of Engineering has selected the US Electric Power Grid as the supreme engineering achievement of the 20th century. Yet, this same grid is struggling to keep up with the increasing demand for electricity, its quality and cost. A growing recognition of the need to modernize the grid to meet future challenges has found articulation in the vision of a Smart Grid in using new control strategies that are intelligent, distributed, and adaptive. The objective of this work is to develop smart control systems inspired from the biological Human Immune System to better manage the power grid at the both generation and distribution levels. The work is divided into three main sections. In the first section, we addressed the problem of Automatic Generation Control design. The Clonal Selection theory is successfully applied as an optimization technique to obtain decentralized control gains that minimize a performance index based on Area Control Errors. Then the Immune Network theory is used to design adaptive controllers in order to diminish the excess maneuvering of the units and help the control areas comply with the North American Electric Reliability Corporation\u27s standards set to insure good quality of service and equitable mutual assistance by the interconnected energy balancing areas. The second section of this work addresses the design and deployment of Multi Agent Systems on both terrestrial and shipboard power systems self-healing using a novel approach based on the Immune Multi-Agent System (IMAS). The Immune System is viewed as a highly organized and distributed Multi-Cell System that strives to heal the body by working together and communicating to get rid of the pathogens. In this work both simulation and hardware design and deployment of the MAS are addressed. The third section of this work consists in developing a small scale smart circuit by modifying and upgrading the existing Analog Power Simulator to demonstrate the effectiveness of the developed technologies. We showed how to develop smart Agents hardware along with a wireless communication platform and the electronic switches. After putting together the different designed pieces, the resulting Multi Agent System is integrated into the Power Simulator Hardware. The multi Agent System developed is tested for fault isolation, reconfiguration, and restoration problems by simulating a permanent three phase fault on one of the feeder lines. The experimental results show that the Multi Agent System hardware developed performed effectively and in a timely manner which confirms that this technology is very promising and a very good candidate for Smart Grid control applications

    Tiedonsiirto osana strategista verkon suunnittelua ja kehittämistä

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    Advanced automation functionalities present a viable alternative for improving the reliability level experienced by the customers in a electricity distribution network in addition to other methods. The requirements imposed on information and communication systems vary according to the chosen implementation of the automation features. The purpose of this study is to examine two functionalities and their requirements. Main objective is to clarify the main differences between alternative implementation options and to support the decision making process of the distribution system operator by a financial evaluation of the functionalities. The thesis consists of two parts. The chosen automation solutions, multi-level protection of medium voltage feeders and automated fault location, isolation and restoration, are introduced and examined in the first part. The basis for economic viability studies are also identified and discussed. In the second part, the financial aspect is explored through case analysis and with reference to current regulatory framework. Three fundamental operation alternatives are found for both automation functionalities. The requirements set for field equipment, communication network and control center IT systems range from similar to those of present ones to a demand of highly intelligent integrated system. Especially the scenarios with independent field agents utilizing distributed decision making provide challenges to system design. The effect on reliability of the network is assessed in typical rural and urban environment. Both of the features presented show a potential for improvement. The resulting customer outage cost benefits are notably greater in rural area, but some advantage is also gained in urban environment. However, the needed investments in urban network surpass the economic benefits. In rural network the implementation is profitable, provided that the current IT and communication systems are adequate or only part of the system require renewal

    Cloud computing for energy management in smart grid - an application survey

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    The smart grid is the emerging energy system wherein the application of information technology, tools and techniques that make the grid run more efficiently. It possesses demand response capacity to help balance electrical consumption with supply. The challenges and opportunities of emerging and future smart grids can be addressed by cloud computing. To focus on these requirements, we provide an in-depth survey on different cloud computing applications for energy management in the smart grid architecture. In this survey, we present an outline of the current state of research on smart grid development. We also propose a model of cloud based economic power dispatch for smart grid
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