The goal of arc-flash protection is to minimize the damaging effects of released energy, which requires very fast and reliable communication among protection system components. In addition to discussing communication requirements and options for sensors, current transformers, relays, circuit breakers, and upper level control systems, this paper introduces and evaluates the benefits and drawbacks of new IEC 61850-based communication options.
Do IT administrators violate arc flash requirements
when they turn off or reset a branch circuit breaker?
What about swapping out a rack power strip? Most
data center operators are familiar with fire safety and
shock hazard protection, but are less familiar with arc
flash safety. Three IT trends have increased the
severity of a potential arc flash in the IT space; higher
data center capacities, higher rack densities, and
higher efficiency designs.
This paper discusses these three trends in the context
of arc flash safety within the IT space. Arc flash is
explained, potential areas of concern in the IT space
are identified, and compliance with associated regulations
is discussed.
A Consideration of Medium Voltage Substation Primary ApplicationsSchneider Electric
Copyright AIST Reprinted with Permission. Presented at the 2013 Iron and Steel Technology Conference and Exposition (AISTech 2013). Unit substations have long served as the method for reducing voltage from higher distribution levels to lower, locally usable voltages. One of the main considerations affecting the design of the substation and the electrical protection and distribution system as a whole is the primary switching device of a substation. By comparing the abilities and options inherited with both types of primary switching devices, an informed decision can be made for specific system designs.
A quick reference guide highlighting the 2014 changes in the National Electrical Code and the associated impact on engineers, contractors, and inspectors.
Operational Cost Avoidance through Harmonic Mitigation in Industrial Environm...Schneider Electric
Industrial sites suffer from margin erosion because operations and equipment costs are not efficiently controlled. Such costs can be avoided if the proper harmonic mitigation solution is implemented. This paper reviews several approaches to harmonic mitigation and identifies best practices.
Do IT administrators violate arc flash requirements
when they turn off or reset a branch circuit breaker?
What about swapping out a rack power strip? Most
data center operators are familiar with fire safety and
shock hazard protection, but are less familiar with arc
flash safety. Three IT trends have increased the
severity of a potential arc flash in the IT space; higher
data center capacities, higher rack densities, and
higher efficiency designs.
This paper discusses these three trends in the context
of arc flash safety within the IT space. Arc flash is
explained, potential areas of concern in the IT space
are identified, and compliance with associated regulations
is discussed.
A Consideration of Medium Voltage Substation Primary ApplicationsSchneider Electric
Copyright AIST Reprinted with Permission. Presented at the 2013 Iron and Steel Technology Conference and Exposition (AISTech 2013). Unit substations have long served as the method for reducing voltage from higher distribution levels to lower, locally usable voltages. One of the main considerations affecting the design of the substation and the electrical protection and distribution system as a whole is the primary switching device of a substation. By comparing the abilities and options inherited with both types of primary switching devices, an informed decision can be made for specific system designs.
A quick reference guide highlighting the 2014 changes in the National Electrical Code and the associated impact on engineers, contractors, and inspectors.
Operational Cost Avoidance through Harmonic Mitigation in Industrial Environm...Schneider Electric
Industrial sites suffer from margin erosion because operations and equipment costs are not efficiently controlled. Such costs can be avoided if the proper harmonic mitigation solution is implemented. This paper reviews several approaches to harmonic mitigation and identifies best practices.
(a)What do you mean by smart substation, smart feeders & Transmission system?
(b)What is need of smart substation, smart feeders & Transmission system?
(c) What are various merits and benefits of smart substation, smart feeders & Transmission system?
(d) Various technologies to make adjusting system into smart substation, smart distribution & Transmission system?
GRID INTERCONNECTION OF RENEWABLE ENERGY SOURCES AT DISTRIBUTION LEVEL WITH P...Pradeep Avanigadda
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This project presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/ Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.
Link vue system offer safety for human and assets (alert 24 x7)Mahesh Chandra Manav
Now Technologies Support Infrastructure offering Human Safety and Industrial Safety and Control Monitoring of Valuable Assets.
Indian Govt is very keen to ensure safety of Human Lives Installation of CCTV and LED Street Light for maximum place to reduce Darkness and this will help to stop criminal activities.
All Public Place , Public Transportation , Shopping Malls , Cinema Halls, Hotels ,Hospitals , Devotional Place , School ,Colleges, Universities, Govt and Pvt Offices, Defense Infra , Railway Station ,Metro Station , Airport Infra, Industrial Plants,
Govt of India Instructed all Liquor Manufacturing , Bottling, Storage and Selling Outlets to Install CCTV which will be access to Excise Central Offices.
Further Advise All Railway Coaches and Station Building should be equipped CCTV .
We request all Architect, MEP and Electrical Consultants, EPC Project and Electrical Contract Companies to send us inquiries and advise for Webinar .
Mahesh Chandra Manav
HOD
Link Vue System Pvt Ltd
India Australia
M-9811247237
manav.chandra@linkvuesystem.com
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Cable Conductor Sizing for Minimum Life Cycle CostLeonardo ENERGY
Energy prices are high and expected to rise. All CO2 emissions are being scrutinized by regulators as well as by public opinion. As a result, energy management has become a key factor in almost every business. To get the most out of each kilowatt-hour, appliances must be carefully evaluated for their energy efficiency.
It is an often overlooked fact that electrical energy gets lost in both end-use and in the supply system (cables, busbars, transformers, etc.). Every cable has resistance, so part of the electrical energy that it carries is dissipated as heat and is lost.
Such energy losses can be reduced by increasing the cross section of the copper conductor in a cable or busbar. Obviously, the conductor size cannot be increased endlessly. The objective should be the economic and/or environmental optimum. What is the optimal cross section necessary to maximize the Return on Investment (ROI) and minimize the Net Present Value (NPV) and/or the Life Cycle Cost (LCC)?
This paper will demonstrate that the maximizing of the ROI results in a cross section that is far larger than which technical standards prescribe. Those standards are based entirely on safety and certain power quality aspects. This means there is room for improvement—a great deal of improvement in fact.
DLPS is a kind of automatic lightning protection control system, which is applied to automatically calculate and carry out the dynamic preventive actions for a Smart Grid/power grid.
Power Adapter Design for 400 V DC Power Distribution in Electronic SystemsVicor Corporation
This white paper describes the design of power adaptors for systems that distribute power using 400 V DC. The paper particularly considers telecom and data center equipment.
This Paper is aimed at analyzing the few important Power System equipment failures generally
occurring in the Industrial Power Distribution system. Many such general problems if not resolved it may
lead to huge production stoppage and unforeseen equipment damages. We can improve the reliability of
Power system by simply applying the problem solving tool for every case study and finding out the root cause
of the problem, validation of root cause and elimination by corrective measures. This problem solving
approach to be practiced by every day to improve the power system reliability. This paper will throw the light
and will be a guide for the Practicing Electrical Engineers to find out the solution for every problem which
they come across in their day to day maintenance activity.
Playing with arduino open source h/w for mobile-centric servicesJunhyuk Lee
Playing with arduino open source h/w for mobile-centric services
2014년 9월 24일
통신학회 강의
개요 : 오픈소스 하드웨어를 기반으로 모바일과 클라우드 개발하는 방법 소개
1. 아두이노 소개 : 아두이노의 특징 및 IoT와의 상관관계 설명
2. 무선 통신 모듈 실습 : XBee, BT, WiFi 사용하기
3. 아두이노 YUN과 Temboo를 이용한 웹 API 활용
4. 아두이노 MEGA ADK를 이용한 안드로이드 기기와의 통신
(a)What do you mean by smart substation, smart feeders & Transmission system?
(b)What is need of smart substation, smart feeders & Transmission system?
(c) What are various merits and benefits of smart substation, smart feeders & Transmission system?
(d) Various technologies to make adjusting system into smart substation, smart distribution & Transmission system?
GRID INTERCONNECTION OF RENEWABLE ENERGY SOURCES AT DISTRIBUTION LEVEL WITH P...Pradeep Avanigadda
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This project presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/ Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.
Link vue system offer safety for human and assets (alert 24 x7)Mahesh Chandra Manav
Now Technologies Support Infrastructure offering Human Safety and Industrial Safety and Control Monitoring of Valuable Assets.
Indian Govt is very keen to ensure safety of Human Lives Installation of CCTV and LED Street Light for maximum place to reduce Darkness and this will help to stop criminal activities.
All Public Place , Public Transportation , Shopping Malls , Cinema Halls, Hotels ,Hospitals , Devotional Place , School ,Colleges, Universities, Govt and Pvt Offices, Defense Infra , Railway Station ,Metro Station , Airport Infra, Industrial Plants,
Govt of India Instructed all Liquor Manufacturing , Bottling, Storage and Selling Outlets to Install CCTV which will be access to Excise Central Offices.
Further Advise All Railway Coaches and Station Building should be equipped CCTV .
We request all Architect, MEP and Electrical Consultants, EPC Project and Electrical Contract Companies to send us inquiries and advise for Webinar .
Mahesh Chandra Manav
HOD
Link Vue System Pvt Ltd
India Australia
M-9811247237
manav.chandra@linkvuesystem.com
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Cable Conductor Sizing for Minimum Life Cycle CostLeonardo ENERGY
Energy prices are high and expected to rise. All CO2 emissions are being scrutinized by regulators as well as by public opinion. As a result, energy management has become a key factor in almost every business. To get the most out of each kilowatt-hour, appliances must be carefully evaluated for their energy efficiency.
It is an often overlooked fact that electrical energy gets lost in both end-use and in the supply system (cables, busbars, transformers, etc.). Every cable has resistance, so part of the electrical energy that it carries is dissipated as heat and is lost.
Such energy losses can be reduced by increasing the cross section of the copper conductor in a cable or busbar. Obviously, the conductor size cannot be increased endlessly. The objective should be the economic and/or environmental optimum. What is the optimal cross section necessary to maximize the Return on Investment (ROI) and minimize the Net Present Value (NPV) and/or the Life Cycle Cost (LCC)?
This paper will demonstrate that the maximizing of the ROI results in a cross section that is far larger than which technical standards prescribe. Those standards are based entirely on safety and certain power quality aspects. This means there is room for improvement—a great deal of improvement in fact.
DLPS is a kind of automatic lightning protection control system, which is applied to automatically calculate and carry out the dynamic preventive actions for a Smart Grid/power grid.
Power Adapter Design for 400 V DC Power Distribution in Electronic SystemsVicor Corporation
This white paper describes the design of power adaptors for systems that distribute power using 400 V DC. The paper particularly considers telecom and data center equipment.
This Paper is aimed at analyzing the few important Power System equipment failures generally
occurring in the Industrial Power Distribution system. Many such general problems if not resolved it may
lead to huge production stoppage and unforeseen equipment damages. We can improve the reliability of
Power system by simply applying the problem solving tool for every case study and finding out the root cause
of the problem, validation of root cause and elimination by corrective measures. This problem solving
approach to be practiced by every day to improve the power system reliability. This paper will throw the light
and will be a guide for the Practicing Electrical Engineers to find out the solution for every problem which
they come across in their day to day maintenance activity.
Playing with arduino open source h/w for mobile-centric servicesJunhyuk Lee
Playing with arduino open source h/w for mobile-centric services
2014년 9월 24일
통신학회 강의
개요 : 오픈소스 하드웨어를 기반으로 모바일과 클라우드 개발하는 방법 소개
1. 아두이노 소개 : 아두이노의 특징 및 IoT와의 상관관계 설명
2. 무선 통신 모듈 실습 : XBee, BT, WiFi 사용하기
3. 아두이노 YUN과 Temboo를 이용한 웹 API 활용
4. 아두이노 MEGA ADK를 이용한 안드로이드 기기와의 통신
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Modelling and Implementation of Microprocessor Based Numerical Relay for Prot...Kashif Mehmood
This paper includes the design and implementation of Numerical Relay that can protect the equipment against over-voltage, over-current and under voltage. Although, every power system is subjected to faults and these faults can severe damage to the power system. Therefore, it is necessary
to observe and resolve in time to avoid a large damage such as blackouts. For this purpose, there
should be some sensing devices, which give signals to the circuit breakers for preventing of power
system damages. The multipurpose relays have much importance role in power system for sensing
and measuring the amplitude of faults. Numerical relay provides settings of over-current, overvoltage and under voltage values. Simulations have been carried out using Proteus software along
with tested on hardware with Arduino Uno Microcontroller that proves the working and operation of
numerical relay.
More Electric:
Our world is becoming More Electric. Almost everything we interact with today is either already electric or becoming electric. Think about it. From the time you start your day in the morning to the time you finish your day – your home, your car, your work, your devices, your entertainment – almost everything is electric. Imagine the energy needed to power this. Electricity consumption will increase by 80% in next 25 years
More Connected: Our lives are also becoming more connected. The Internet has already transformed the way we live, work and play. Now the Connected Things is going to take this to a brand new level. 50 billion things connected in the next 5 years.
More Distributed: With such a widespread electrification and connectivity, energy models need rethinking as well. Which is why the generation of power needs to be closer to users. Distributed Energy is rapidly evolving globally. This is positive energy – renewable. In 2014 , Renewables overtook fossil fuels in investment value, with $295bn invested in renewables compared to $289bn invested in fossil fuels. And it is getting cheaper to do this.
More Efficient: When our world is more electric, more connected and more distributed, new opportunities emerge and allows us to tap into even more efficiency – in industrial processes, in the energy value chain, in buildings, in transportation, in the global supply chain and even in the comfort and peace-of-mind of our homes.
With more than $18 billion in M&A activity in the first half of last year alone, the colocation industry is riding the bubble of rapid growth. Colocation data center providers are being evaluated by a wide range of investors, with varying experience and perspectives. Understanding the evaluation criteria is a critical competency for attracting the right type of investor and financial commitment for your colocation business and this is why we have invited today’s speaker to present.
Steve Wallage Steve Wallage is Managing Director of BroadGroup Consulting. Steve brings 25 years of industry experience, holding senior roles at Gartner Group, IDC, CGI and IBM before joining BroadGroup 10 years ago. In his responsibilities at BroadGroup Steve has led many due diligence projects for investors evaluating colocation companies.
In this briefing we explore the Phaseo power supplies and transformers offer presentation and application samples.
For more details:
Industrial%20Automation%20and%20Control&parent-category-id=4500&parent-subcategory-id=4510
We’ve all been hearing about how robust the market for data center space is, but a presentation by an investment banker who has his finger on the pulse on the market day in and day out gave me a new appreciation for how great the opportunity really is.
Herb May is a partner and managing director with DH Capital, an investment bank founded 15 years ago in New York that is focused on the Internet infrastructure space. His company has been involved in close to 100 deals, representing almost $20 billion in value. Most of DH Capital’s work is as a mergers and acquisitions advisor, but raising capital is a growing percentage of its business. The point is, the company understands the financials behind data centers and colocation companies inside and out.
At Schneider Electric, in the IT Division, our core business has always been focused on delivering the highest level of availability to critical technologies, systems and processes. We’ve done this through our award winning, industry-leading and highest quality products and solutions, including UPS, Cooling, Rack Systems, DCIM and Services.
In this new digital era, we see a world that is always-on.
Always on to meet the needs of the highest notion of “access” to goods and services
Always on to be the solid, reliable foundation of digital transformation for businesses
Our mission is: To empower the digital transformation of our customers by ensuring their critical network, systems and processes are highly available and resilient.
In this briefing we explore the Magelis Basic HMI offer presentation and application samples.
For more details:
https://www.schneider-electric.com/en/product-range/61054-magelis#search
In this briefing, we explore the Zelio time relay offer presentation and application samples.
For more details:
http://www.schneider-electric.com/en/product-range/529-zelio-time?parent-category-id=2800&parent-subcategory-id=2810&filter=business-1-industrial-automation-and-control
Spacial, Thalassa, ClimaSys Universal enclosures BriefingSchneider Electric
Discover more about Universal Enclosures and how to select the one you need.
For more information:
http://www.schneider-electric.com/en/product-category/5800-enclosures-and-accessories/?filter=business-1-industrial-automation-and-control
Learn more about "what is a solid state relay", key features and targeted applications.
For more details:
http://www.schneider-electric.com/en/product-range/60278-zelio-relays?parent-category-id=2800&filter=business-1-Industrial%20Automation%20and%20Control
Learn more about what an HMI does and the main components and a look at a typical HMI.
Further details:
http://www.schneider-electric.com/en/product-category/2100-HMI%20(Terminals%20and%20Industrial%20PC)?filter=business-1-Industrial%20Automation%20and%20Control
Where will the next 80% improvement in data center performance come from?Schneider Electric
Rick Puskar, Head of Marketing for Schneider Electric's IT Division presents at the Gartner Symposium in Barcelona November 8th, 2017. In this presentation Rick discusses where the next 80% improvement in data center performance will come from with a focus on the speed, availability and reliability of data. Learn how a cloud-based data center infrastructure management as a service architecture like Schneider Electric's EcoStruxure IT can drive such aggressive goals around data center performance.
Learn how EcoStruxure is digitizing industry with IIoT to increase end-to-end operational efficiency with more dynamic control for better business results.
Learn more about our System Integrator Alliance Program - A global partnership transforming industry and infrastructure by helping them make the most of their processes, the most of their assets and the most of their energy.
EcoStruxure, IIoT-enabled architecture, delivering value in key segments.Schneider Electric
As presented during the Alliance 2017 event, learn how to deliver integrated solutions based on EcoStruxure, our IIoT-enabled architecture for Wastewater, Food and Beverage and Mining, Minerals and Metals.
A Practical Guide to Ensuring Business Continuity and High Performance in Hea...Schneider Electric
Within healthcare facilities, high availability of systems is a key influencer of revenue and patient safety and satisfaction. Three important critical success factors need to be addressed in order to achieve safety and availability goals. These include exceeding the facility’s level of regulatory compliance, a linking of business benefits to the maintenance of a safe and an “always on” power and ventilation environment, and a sensible approach to technology upgrades that includes new strategies for “selling” technological improvements to executives. This reference guide offers recommendations for identifying and addressing each of these issues.
Connected Services Study – Facility Managers Respond to IoTSchneider Electric
According to a new 2017 study commissioned by Schneider Electric, facility managers are increasingly looking to leverage the Internet of Things (IoT) by implementing new digital technologies like intelligent analytics to improve maintenance decisions and operations. Explore the full results on how facility managers are reacting to IoT when it comes to facility maintenance.
Learn more about cabling and accessories and the complete ranges available featuring 3 types of cable to suit the envirionment. For more details: http://www.schneider-electric.com/en/product-subcategory/88035-cordset-and-connectors/?filter=business-1-industrial-automation-and-control&parent-category-id=4900
This briefing will look at the general purpose of Photoelectric sensors and Photoelectric fork and frame sensors. For more details: http://www.tesensors.com/global/en/product/photoelectric/xu/?filter=business-1-automation-and-control&parent-category-id=4900/
A world-class global brand offering a comprehensive line of Limit Switches complying with international standards: IEC, UL, CSA, CCC, GOST. For more details: http://www.tesensors.com/global/en/product/limit-switches/xc-standard/?cat_id=BU_AUT_520_L4&conf=sensors&el_typ=node&nod_id=0000000002&prev_nod_id=0000000001&scp_id=Z000
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
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Evaluating the Arc-Flash Protection Benefits of IEC 61850 Communication
1. Evaluating the Arc-Flash
Protection Benefits of IEC 61850
Communication
by Anssi Jäntti, Olavi Vähämäki, and Juha Rintala of Schneider Electric
and Lauri Kumpulainen and Kimmo Kauhaniemi of the University of Vaasa, Finland
998-2095-01-30-15AR0
Executive summary
The goal of arc-flash protection is to minimize the
damaging effects of released energy, which requires
very fast and reliable communication among protection
system components. In addition to discussing
communication requirements and options for sensors,
current transformers, relays, circuit breakers, and
upper level control systems, this paper introduces and
evaluates the benefits and drawbacks of new IEC
61850-based communication options.
2. Evaluating the Arc-Flash Protection Benefits of IEC 61850 Communication
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Arcing faults in switchgear are rare events but their consequences can be severe.
Characterized as electrical explosions, the radiation, heat, pressure waves, and flying
particles associated with an arc flash can injure or kill personnel. These impacts can also
destroy systems components, ruin switchgear, and trigger process outages that result in
unanticipated expense.
Due to the explosive nature of arcing faults, traditional overcurrent protection is often
ineffective. A number of published articles in scientific publications discuss advanced
methods for addressing these issues.1 2
The IEEE, for instance discusses the concept of incident energy (IE), which they define as
the amount of energy impressed on a surface, a certain distance from the source, generated
during an electrical arc event.3
Incident energy calculations were developed for defining arc-
flash protection boundaries and for the development of protection strategies.
These calculations can also be applied when comparing different protection approaches. IE
levels can be calculated using parameters of voltage level, working distance, bolted fault
short-circuit current, and arcing time. The key parameter to influence is that of arcing time,
i.e., the time required for protection to operate.
In traditional, relay-based protection, arcing time consists of arc detection time, the protection
relay’s operation time, the operation time of the device that extinguishes the arc, and the
communication delay between components. Either a circuit breaker (CB), fuse, or a short-
circuit device extinguishes the arc (see Figure 1, scenario 1). Protection based on the
simultaneous detection of overcurrent and light provides extremely fast operation (see Figure
1, scenario 2). When applying this protection approach, the dominant component of the
arcing time is the operation time of the circuit breaker (with that being some tens of
milliseconds). On the other hand, as can be seen in Figure 1, relay time is dominant in
traditional overcurrent protection.
1
J.A. Kay, J. Arvola, L. Kumpulainen, Protecting at the Speed of Light. IEEE Industry Applications
Magazine, May/June 2011. pp. 12-18
2
D. Shipp, D. Wood, “Mitigating Arc-Flash Exposure”, IEEE Industry Applications Magazine, July/August
2011, pp. 28-37
3
IEEE Std 1584™-2002, IEEE Guide for Performing Arc-Flash Hazard Calculations, IEEE, 2002.
Introduction
Figure 1
The composition of arcing
time in light- and overcurrent-
based protection compared to
traditional overcurrent
protection
Relay Time
Circuit breaker
time
Relay time
Scenario 1: Fast, conventional overcurrent protection
Scenario 2: Light and overcurrent‐based protection
Circuit breaker
time
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Arcing time of only a few milliseconds can be achieved by using a short-circuit device. When
detecting an arcing fault via simultaneous light and overcurrent detection, the arc protection
system sends a trip command to both the very fast short-circuit device and the appropriate
circuit breaker. The short-circuit device then creates an intentional short circuit and
extinguishes the arc within a few milliseconds by eliminating the voltage. Meanwhile, the
circuit-breaker begins to operate and breaks the current after some tens of milliseconds.
Short-circuit devices are not applied on a regular basis today, but are receiving increased
interest.
Pre-emptive protection is another approach that is under development. This approach
employs on-line monitoring to sense early signs of slowly developing faults. In medium
voltage systems, partial discharge (PD) detection can efficiently discover early signs of
isolation deterioration. However, one cannot apply the PD approach in low voltage systems,
though thermal sensors have proven to be an effective means of detecting potential arc fault
causes such as loose contacts.4
Communication between various protection system components is an essential element of all
the aforementioned arc-flash protection approaches. Communication to an upper-level control
system is also required. This paper reviews communication options and compares a
traditional system to a new, IEC 61850-based approach.
Fast light detection
Fault arc detection times can be as short as 0.5-2ms. Testing reveals a strong correlation
between arc power and the intensity of observed light.5
As a result, an arc can be detected
almost immediately via a light-sensitive sensor such as photodiode (a point type of sensor) or
optical fiber (a loop type of sensor). No precise, universal threshold value yet exists that can
always differentiate between light emanating from arcing faults and light derived from other
sources. However, practical experience concludes that a sensitivity of approximately 10,000
lux gives excellent results. Sensors with this level of sensitivity are likely to detect the light in
all relevant arc fault situations involving metal-enclosed switchgear. At the same time, they
maintain a low risk of false activation. This is especially true in cases where arc detection
accompanies overcurrent detection.
Fast overcurrent detection
To eliminate possible nuisance tripping caused by external light, a current condition (i.e.,
detection of overcurrent) is often required in parallel with light detection. Normal current
transformers can measure the current. In arc-flash protection applications, however,
operation times must be minimized. Special methods can rapidly detect overcurrent. At the
International Conference on Electricity Distribution (CIRED conference)6
an algorithm was
described that employs instantaneous sampled current values, and 1 ms detection times in
three-phase faults were demonstrated. An IEEE publication has described an approach that
takes advantage of current waveform discontinuity (change in di/dt) to achieve very fast
overcurrent detection.7
Applying an analog comparator can also enable fast overcurrent
detection.
4
H. B. Land, III, C.L. Eddins, L. R. Gauthier, Jr., J. M. Klimek, Design of a Sensor to Predict Arcing
Faults in Nuclear Switchgear. IEEE Transactions on Nuclear Science, Vol. 50, Issue 4, 2003, pp. 1161-
1165
5
B. Melouki, M. Lieutier, A. Lefort, The correlation between luminous and electric arc characteristics.
Journal of Physics D: Applied Physics, Vol. 29, Number 11, 1996, pp. 2907-2914
6
M. Öhrström, L. Söder, H. Breder, Fast fault detection for peak current limitation based on few
samples. Proceedings of CIRED 2003, Barcelona, 12-15 May, 2003
7
R. Garzon, The Arc Terminator, IEEE Industry Applications Magazine, Vol. 9, Issue 3, 2003, pp. 51-55
Simultaneous
light and
overcurrent
detection
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Because many arcing faults start as single-phase faults, phase-to-earth fault detection is also
justified. If an arc is detected and eliminated before it escalates into a high-power, three-
phase fault, the damage is less.
How to avoid nuisance tripping caused by switching arcs
In almost all cases, in both medium (MV) and low voltage (LV) systems, the trip condition of
simultaneous light and overcurrent detection is a proven success. However, some low
voltage circuit breakers (air-magnetic types) emit light while operating. Use of a special type
of light sensor (which is less sensitive or designed for a limited wavelength range) or applying
pressure sensors can mitigate this problem.
Existing system architecture
This section describes the operating principles of a state-of-the-art arc-flash protection
system. Other systems operate under similar principles. Although its basic functionality is
fairly simple, the complete arc-flash protection system consists of several components.
Providing selective protection by dividing installations into individual protection zones is a key
approach. Figure 2 illustrates a rather complicated design with different parts of the
installation marked as different protection zones. The arc-flash protection system mainly
comprises the following four types of components:
Sensors (light or current)
I/O units
Central units
Communication cables
The system requires additional components (e.g., a battery-backed auxiliary power supply
system) but these are omitted for the sake of simplicity.
Figure 2
An example of a dedicated
arc-flash protection system
for an MV substation
Dedicated arc-
flash protection
system
communication
approach
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On the left side of Figure 2, point sensors detect light. On the right side, the installation is
equipped with fiber optic sensors. I/O units read the sensors and send sensor information to
the common communication pathway. The point sensors connect to I/O units in Zone 2 (A)
and fibers connect to an I/O unit in Zone 3 (B). I/O units can perform a local trip based on
information from the sensors connected to the I/O device itself, or based on a signal from any
other I/O unit in the same zone. All light sensors connected to one I/O unit can only belong to
one particular zone. Five zones are available, one of which is always reserved for transferring
overcurrent information.
Current can be measured by current transformers connected either directly to the arc-flash
protection central unit (C) or to a current I/O unit (D). All units are linked to the central unit by
the communication cables (E). Circuit breakers receive trip commands from the central unit or
from the I/O units via circuit breaker wiring (F).
The system architecture is centralized and the central unit is always required. The central unit
monitors the system (self-supervision) and maintains communication. It can also perform trips
based on the light sensors connected to the central unit itself or based on the information
received from the I/O units. In addition, the central unit can communicate with SCADA
systems by using various standard protocols.
Dedicated arc-flash protection system communication
I/O units are linked to the central unit with modular cables. Each I/O unit and the central unit
have two modular cable connectors. Therefore, if one wants to connect more than two I/O
units to the system, they must be daisy-chained. That means that only line topology is
supported. To be precise, the devices do not actually act as repeaters by reading the
information received from the communication pathway and then passing it on to the next
device. The topology actually is not a line, but a bus. Figure 3 illustrates these two different
network topologies among other common ones.
A major advantage of using a bus topology is that the devices do not have to act as
repeaters. This approach supports very fast communication, as adding new devices to the
network does not slow communication.
Figure 3
Commonly used network
topologies
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Two somewhat independent communication pathways are utilized when communicating
between I/O units and the central units. Both reside inside the same modular cable but utilize
different wires. The first of these communication pathways is a simple, fast, infinitely
repeating frame, only a few bits long, containing zone-based activation information. Each of
the devices in the network can use this to report activation (i.e., detected light or current) in
any of the available zones. The second communication pathway is slower communication
used during, for example, installation, querying sensor status, or releasing latches. Both of
these communication types are proprietary and nonstandard. Also, both of these
communication types are controlled by a central unit. There is no communication through the
modular cable between the I/O units without the central unit being present and operational.
These proprietary communication pathways are also designed for relatively short-range
communication.
Power supply to I/O units
In addition to communication, the modular cable is used to supply power to the I/O units from
the central unit. An external power supply is required after a certain amount of cabling or
number of I/O units. When connected to an external power supply, an I/O unit can further
distribute power to the surrounding I/O units through the modular cable.
Proprietary communication system limitations
Experiences with the communication system described previously have been positive.
Regarding speed and reliability, performance is excellent. However, this system has some
limitations. The system is nonstandard and designed for relatively short-range
communication; the maximum length of total cabling is about 100m. The topology of the
network must always be a bus, and this poses further limitations. The maximum number of
zones is five, and the proprietary communication protocol does not provide a convenient way
of increasing this. Furthermore, in certain installations, it would be advantageous to configure
the sensors in a single device to reside in more than one zone.
Communication system performance
A series of tests were conducted in order to determine the performance of the communication
system described above. Several configurations were constructed using key components;
light sensors, I/O units, and a central unit. Several I/O units were always present in each of
the different configurations in order to simulate actual installations.
Ten sensors were connected to each of the I/O units in the case of point type sensors and
one sensor in the case of fiber type sensors. Regarding the point sensors, a total of 10
sensors were always activated simultaneously, simulating the worst case in an actual
installation. A piece of sheet metal was used to fasten the sensors as close to each other as
possible in order to ensure that they would activate at the same time. A professional-grade
camera flash was used to activate the sensors.
As mentioned, the units had to be daisy-chained with the modular cable. Different types and
lengths of cables were used during the testing. In these tests, only modular cable was used
to link the I/O units to each other and to the central unit. The central unit was always
positioned at one end of the bus and the I/O unit with the activated sensor at the opposite
end. No additional power wiring or power supplies were used. Figure 4 illustrates one of the
test installations.
In order to evaluate performance, system reaction time (time from light detection to trip) was
measured. This was achieved by using an oscilloscope to measure the trip times of both the
central unit and the I/O unit on which the sensors were activated. Trip times were measured
from the point of the sensors activating on the last I/O unit to the output relay contacts closing
7. Evaluating the Arc-Flash Protection Benefits of IEC 61850 Communication
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on both the central unit and on the I/O unit itself. The relays in the devices were configured to
latch on light detection.
A four-channel oscilloscope was used to perform the measurements. The first channel of the
oscilloscope was connected to one of the activated light sensors. The second channel was
used to measure the operating voltage of the last I/O unit in the chain during trip/light
detection. The third channel was connected to the output relay of the last I/O unit, and the
fourth channel was connected to the output relay on the central unit.
The oscilloscope Delta Time feature was used to measure trip delays. Channel 1 rising edge
and channel 3 and 4 falling edges were used as the signal sources. Trip delay measurements
were performed 10 times for each test case. An example is illustrated in Figure 5.
Figure 4
Configuration of test case #2,
shown as an example
Figure 5
Oscilloscope with the voltage
and Delta Time
measurements
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The following cable lengths were used during testing: 2 meters, 15 meters, and 30 meters. In
situations where different cables lengths were used in one test, the longest cable was always
connected between the master and the first I/O unit because this is the worst case. The
following combinations were tested:
1. Five point type sensor units, five 2m cables
2. Four point type sensor units, one 15m cable, three 2m cables
3. Three point type sensor units, one 30m cable, two 2m cables
4. Five fiber type sensor units, five 2m cables
5. Four fiber type sensor units, one 15m cable, three 2m cables
6. Three fiber type sensor units, one 30m cable, two 2m cables
7. Four point type sensor units, one current sensor unit, five 2m cables
8. Three point type sensor units, one current sensor unit, one 15m cable, three 2m
cables
9. Two point type sensor units, one current sensor unit, one 30m cable, two 2m cables
Ten measurements were performed for each of the nine test cases. Table 1 lists the mean,
minimum, and maximum trip times of these tests. The measurements were taken from the
mechanical output relays, so the delay caused by the relays is included in the measurements.
Use of high-speed semiconductor/hybrid outputs would have produced better results.
The results show that fiber type sensors are slightly faster than point type sensors. The tests
also show that a slight variation of the I/O units’ trip times exists depending on the
configuration. Based on the results, it can be determined that with point type sensors, the
average trip time for the central unit is about 6.29ms. The average trip time for the I/O unit is
about 10.61ms. With fiber sensors, the respective trip times are 4.75ms and 7.79ms.
Central unit trip time (ms) I/O unit trip time (ms)
Test case # Mean Min Max Mean Min Max
1 6.32 6.2 6.41 10.73 10.23 11.05
2 6.28 6.08 6.46 10.37 9.81 10.75
3 6.28 6.15 6.42 11.16 10.85 11.37
4 4.7 4.62 4.79 7.68 7.53 7.96
5 4.75 4.64 4.88 7.82 7.6 8.28
6 4.81 4.47 4.88 7.86 7.74 8.39
7 6.19 6.07 6.38 10.34 9.82 10.56
8 6.27 6.03 6.45 10.05 9.58 10.58
9 6.37 6.12 6.61 11.01 10.78 11.13
Table 1
Mean, minimum, and
maximum trip times in the
tests
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Ethernet-based communications in general and IEC 61850-based technology in particular are
rarely applied in arc-flash protection systems. However, zone-selective interlocking (ZSI) is a
common application closely related to arc-flash protection. In ZSI, IEC 61850 and Generic
Object Oriented Substation Events (GOOSE) have successfully been utilized,8
but ZSI is
slower than light/overcurrent-based arc-flash protection.9
GOOSE messages are limited to relay-to-relay communications in light/overcurrent-based
arc-flash protection systems.10
GOOSE messaging can also be applied for communication
between other components of arc-flash protection systems: sensors, input/output units,
relays, and circuit breakers. The essential question is whether GOOSE can provide the
required speed and reliability.
In order to avoid delays caused by network traffic, virtual local area networks (VLAN) are
used to separate priority and non-priority traffic on the network.11 12
Another means to
enable very fast communication is to utilize high-speed fiber media for networking the
devices.13 14
Previous studies have shown that the speed of GOOSE-based communication
is as good as direct serial communication.12
Principles of an IEC 61850/GOOSE arc-flash protection system
approach
An IEC 61850/GOOSE-based arc-flash protection system shares the same four basic
components as the proprietary system previously described: sensors, I/O units, central units,
and cables. In this scenario, however, the central unit is an optional component. The system
architecture is distributed instead of centralized, and the system can operate perfectly without
the central unit. This makes the system more robust. The central unit can, however, still serve
as a centralized information collection and communication device that can be used as a
gateway for relaying information to SCADA systems, for example.
The proprietary system differentiates between the arc-flash protection network and the upper-
level communication network (e.g., connection to SCADA) in two ways. First, the protocol in
the arc-flash protection communication is proprietary. It also has separate physical
connectors for the different networks. This is an important factor for improving an
installation’s cybersecurity. The same kind of security can also be achieved when using an
IEC 61850-based approach by having two separate processors, two independent network
stacks, and two physically different Ethernet connectors for the different networks.
The concept of zones still exists in the new system. However, the zone settings in this system
do not need to be configured at the I/O unit level. They can also be set at the sensor level.
8
J. Holbach, Mitigation of Arc Flash hazard by using Protection solution, 60th Annual Conference for
Protective Relay Engineers, IEEE, 2007. pp. 239-250
9
C. Cabrera, S. Chiu, N.K.C. Nair, Implementation of Arc-Flash Protection Using IEC 61850 Goose
Messaging. Conference Record of IEEE International Conference on Power System Technology
(POWERCON), 2012, pp. 1-6
10
G. Rocha, E. Zanirato, F. Ayello, R. Taninaga, Arc-Flash Protection for Low- and Medium-Voltage
Panels. Paper No. PCIC-2011-25, IEEE Petroleum and Chemical Industry Committee Technical
Conference, Toronto, 19-21 Sept. 2011
11
L. Sevov, T.W. Zhao, I. Voloh, The Power of IEC 61850. IEEE Industry Applications Magazine,
Jan/Feb 2013. pp. 60-67
12
F. Dixon, M.T. Yunas, V. Wedelich, J. Howard, H.E. Brown, S.N. Sauer, Y. Xu, T. Markello, W,
Sheikh, Mitigating Arc Flashes Using IEC 61850. IEEE Industry Applications Magazine, Jan/Feb 2014.
pp. 64-69
13
L. Kumpulainen, O. Vähämäki, T. Harju, A. Jäntti, Enhancement of Arc-Flash Protection by IEC
61850. Conference proceedings of PAC World 2012, Budapest, 25-28 June 2012
14
D.C. Mazur, J.A. Kay, J.H. Kreiter, Benefits of IEC 61850 Standard for Power Monitoring and
Management Systems in Forest Product Industries. Conference Record of IEEE Pulp and Paper
Industry Technical Conference, 2013, pp. 69-75
IEC 61850
communication
in arc-flash
protection
systems
10. Evaluating the Arc-Flash Protection Benefits of IEC 61850 Communication
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Each of the sensors can be individually configured to transmit activations of any zone, and
one sensor can even belong to multiple zones. This is true for both light and current sensors.
The number of the zones can be as high as 16. The same zone can contain either light and
current sensors or just one type of sensor. This provides more flexibility for configuration.
Diversity of usable network topologies
The IEC 61850/GOOSE system also uses modular cables. Each I/O unit has two modular
cable connectors as does the proprietary approach, but uses IEC 61850 and GOOSE
communication, which operate over Ethernet. Because communication is Ethernet based, all
topologies supported by Ethernet are also supported by the new arc-flash protection system.
This includes line, star, tree, and mixed or hybrid topologies. Looped connections are not
supported by standard Ethernet, but new I/O units are equipped with special hardware that
can accommodate ring networks.
Power supply
The new system again uses a somewhat similar approach to the previous one; the central
unit can supply power to the I/O units by using a technology sometimes referred to as
“Passive PoE.” This can be described as a somewhat simplified version of the standard PoE
(Power over Ethernet). Some manufacturers have already chosen to support this simplified
version in their products. Limitations imposed by the actual PoE standard15
make
implementation impossible in daisy-chained devices, for example. Limitations still exist
regarding the length of cabling and number of I/O units that the central unit can supply. In
these cases, the I/O units can again be equipped with external power supplies. In future
implementations, separate devices will be able to supply extra power to devices through
modular cables.
Communication
In the IEC 61850/GOOSE system, two distinct types of communication pathways exist: 1. fast
communication for relaying zone information, and 2. lower priority control and configuration
communication pathway. The fast communication is implemented with GOOSE messages
over Ethernet. One advantage of this is that the protocol is standardized. GOOSE protocol
also already implements many features that are useful for arc-flash protection devices. For
example, GOOSE messages are broadcast messages, which support distributed architecture.
GOOSE messages are also constantly repeated and this can be used to keep a count of the
devices present in the network. The GOOSE protocol is also relatively simple. It can be fairly
easily implemented on embedded devices while retaining good performance regarding time
constraints.
When comparing the previously described proprietary communication pathway to GOOSE
messages, the latter has considerably higher overhead in the amount of transferred data and
the amount of time taken to process the communication. This is a natural result of GOOSE
being a more universal way of communicating, while the proprietary system was designed
specifically for the application at hand. However, as considerable communication overhead
already exists from using GOOSE messages and Ethernet, including additional payload
information to the communication frames, there is not a major relative increase in
transmission or processing times. It therefore makes sense to transfer other useful
information in the messages in addition to only the zone information. The same frames
contain, for example, information about the activated sensors and detected errors.
The GOOSE protocol does not support the transferring of, for example, configuration
information. Other parts of the IEC 61850 standard could be used for these purposes.
15
IEEE Standard for Ethernet. IEEE Std 802.3-2012
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However, such an approach represents heavy workloads for small CPUs and is difficult to
implement. To address this issue, a proprietary GOOSE-based protocol was developed.
A major advantage of Ethernet is that connections are limited to 100m only for each link, and
the range can easily be extended with Ethernet switches. Each of the I/O units in the new
system has a built-in switch so the distance between each unit can be up to 100m. There is
no theoretical limit to the maximum length of total cabling. A drawback to this approach is that
each additional hop causes message delays.
Performance of the developed system
As with the traditional arc-flash protection system described earlier in this paper, the
performance (i.e., trip time) of the IEC 61850/GOOSE system was also tested. The tests
were conducted using four prototype devices. A point type arc sensor was connected to one
of the devices, with 0.5m cables used to link the devices. Line topology was used and power
to the devices was provided by using a commercially available Passive PoE-capable Ethernet
switch. The devices were configured so that sensor activation on one of the devices would
cause output to be activated on all devices in the network. As this system does not require a
central unit, these tests were conducted without one. Figure 6 illustrates the system used for
testing.
An oscilloscope was again used to take measurements. The first channel of the oscilloscope
was connected to the same sensor input as the point type arc sensor. The second channel
was connected to the transistor controlling an output relay on each device. Measurements
were repeated 10 times. A two-channel oscilloscope was used and the measurements were
then also repeated four times, while always moving the second oscilloscope channel to the
output of another device.
Table 2 lists the results of the testing. The first column indicates the test number. The second
column is the time from the first device’s arc sensor input activation to the same device’s
output relay control signal activation. The third column is from the first device’s arc sensor
input activation to the second device’s output signal activation and so on. Measurements are
expressed in µs.
Figure 6
Configuration of the GOOSE-
based arc-flash protection
system test setup
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The results show that the average time for a local trip is 53µs and the transfer time from one
device to another is 147µs. Also, based on the results, it can be determined that each hop
seems to create an additional 15.5µs delay.
.
These results cannot be directly compared to the results of the tests conducted on the
traditional system (see Table 1). The measurements of the previous tests took into account
the operating delay of the mechanical relay contacts, whereas these measurements were
taken directly from the transistor controlling the relay. However, comparing the results
demonstrates the fundamental difference in these approaches: In the previously described
system, adding more devices does not directly affect the operational delay. With the
Ethernet-based system, each additional hop slightly increases operation time. This can be
mitigated by using different kinds of network topology that minimize the amount of hops in
the network.
Test # Device 1->1 Device 1->2 Device 1->3 Device 1->4
1 32.8 116 138 172
2 40 160 158 174
3 58.4 136 156 148
4 32.8 156 150 184
5 106.4 180 138 172
6 40.8 159 162 170
7 97.6 128 168 214
8 25.8 156 162 168
9 39.2 120 178 184
10 58.4 102 118 174
11 60.8 168 166 176
12 36.8 134 170 198
13 60 180 182 192
14 42.4 170 190 170
15 52.8 136 198 186
16 29.6 150 180 190
17 49.6 142 148 158
18 95.2 154 136 190
19 41.6 130 148 144
20 51.2 160 158 194
Min 25.8 102 118 144
Max 106.4 180 158 194
Avg 53 147 160 178
Table 2
Measured delays in the
testing of the GOOSE-based
system