Real-Time Hardware-In-the-Loop Testing of IEC 61850 GOOSE based Logically Selective Adaptive Protection of AC Microgrid

The real-time (RT) hardware-in-the-loop (HIL) simulation-based testing is getting popular for power systems and power electronics applications. The HIL testing provides the interactive environment between the actual power system components like control and protection devices and simulated power system networks including different communication protocols. Therefore, the results of the RT simulation and HIL testing before the actual implementation in the field are generally more acceptable than offline simulations. This paper reviews the HIL testing methods and applications in the recent literature and presents a step-by-step documentation of a new HIL testing setup for a specific case study. The case study evaluates improved version of previously proposed communication-dependent logically selective adaptive protection algorithm of AC microgrids using the real-time HIL testing of IEC 61850 generic object-oriented substation event (GOOSE) protocol. The RT model of AC microgrid including the converter-based distributed energy resources and battery storage along with IEC 61850 GOOSE protocol implementation is created in MATLAB/Simulink and RT-LAB software using OPAL-RT simulator platform. The Ethernet switch acts as IEC 61850 station bus for exchanging GOOSE Boolean signals between the RT target and the actual digital relay. The evaluation of the round-trip delay using the RT simulation has been performed. It is found that the whole process of fault detection, isolation and adaptive setting using Ethernet communication is possible within the standard low voltage ride through curve maintaining the seamless transition to the islanded mode. The signal monitoring inside the relay is suggested to avoid false tripping of the relay.©2021 Institute of Electrical and Electronics Engineers. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/This work was mainly carried out in the SolarX research project funded by the Business Finland under Grant No. 6844/31/2018. Some part of this work was carried out during the VINPOWER research project funded by the European Regional Development Fund (ERDF), Project No. A73094. The financial support provided through these projects is greatly acknowledged.fi=vertaisarvioitu|en=peerReviewed

Convergence: the next big step

Recently, web based multimedia services have gained popularity and have proven themselves to be viable means of communication. This has inspired the telecommunication service providers and network operators to reinvent themselves to try and provide value added IP centric services. There was need for a system which would allow new services to be introduced rapidly with reduced capital expense (CAPEX) and operational expense (OPEX) through increased efficiency in network utilization. Various organizations and standardization agencies have been working together to establish such a system. Internet Protocol Multimedia Subsystem (IMS) is a result of these efforts. IMS is an application level system. It is being developed by 3GPP (3rd Generation Partnership Project) and 3GPP2 (3rd Generation Partnership Project 2) in collaboration with IETF (Internet Engineering Task Force), ITU-T (International Telecommunication Union – Telecommunication Standardization Sector), and ETSI (European Telecommunications Standards Institute) etc. Initially, the main aim of IMS was to bring together the internet and the cellular world, but it has extended to include traditional wire line telecommunication systems as well. It utilizes existing internet protocols such as SIP (Session Initiation Protocol), AAA (Authentication, Authorization and Accounting protocol), and COPS (Common Open Policy Service) etc, and modifies them to meet the stringent requirements of reliable, real time communication systems. The advantages of IMS include easy service quality management (QoS), mobility management, service control and integration. At present a lot of attention is being paid to providing bundled up services in the home environment. Service providers have been successful in providing traditional telephony, high speed internet and cable services in a single package. But there is very little integration among these services. IMS can provide a way to integrate them as well as extend the possibility of various other services to be added to allow increased automation in the home environment. This thesis extends the concept of IMS to provide convergence and facilitate internetworking of the various bundled services available in the home environment; this may include but is not limited to communications (wired and wireless), entertainment, security etc. In this thesis, I present a converged home environment which has a number of elements providing a variety of communication and entertainment services. The proposed network would allow effective interworking of these elements, based on IMS architecture. My aim is to depict the possible advantages of using IMS to provide convergence, automation and integration at the residential level

Discrete Multitone Modulation for Maximizing Transmission Rate in Step-Index Plastic Optical Fibres

The use of standard 1-mm core-diameter step-index plastic optical fiber (SI-POF) has so far been mainly limited to distances of up to 100 m and bit-rates in the order of 100 Mbit/s. By use of digital signal processing, transmission performance of such optical links can be improved. Among the different technical solutions proposed, a promising one is based on the use of discrete multitone (DMT) modulation, directly applied to intensity-modulated, direct detection (IM/DD) SI-POF links. This paper presents an overview of DMT over SI-POF and demonstrates how DMT can be used to improve transmission rate in such IM/DD systems. The achievable capacity of an SI-POF channel is first analyzed theoretically and then validated by experimental results. Additionally, first experimental demonstrations of a real-time DMT over SI-POF system are presented and discusse

FTTx Access Networks: Technical Developments and Standardization

This chapter provides a review of factors driving technical development of broadband access networks, mostly toward higher bit rates and symmetrical services, together with a review of “fiber to the x” (FTTx) technologies for fixed access networks, including development and performance limitations of digital subscriber line (DSL) systems using twisted-pair copper cables, as well as fiber to the home systems. Characteristics and standardization of these systems are presented, together with a review of the two main competing broadband technologies: Data over cable service interface specification (DOCSIS) in coaxial cable TV networks and the 4G and 5G wireless networks. Additionally, a short list of recent developments in passive technologies (fibers, cables, and connectors) is included. Finally, the issues related to dismantling of the traditional copper telephone network and ensuring continuity of voice services in emergency situations are analyzed

Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection

In this paper, it is argued that some low-level aspects of the usual IEC 61850 mapping to Ethernet are not well suited to microgrids due to their dynamic nature and geographical distribution as compared to substations. It is proposed that the integration of IEEE time-sensitive networking (TSN) concepts (which are currently implemented as audio video bridging (AVB) technologies) within an IEC 61850 / Manufacturing Message Specification framework provides a flexible and reconfigurable platform capable of overcoming such issues. A prototype test platform and bump-in-the-wire device for tunneling horizontal traffic through AVB are described. Experimental results are presented for sending IEC 61850 GOOSE (generic object oriented substation events) and SV (sampled values) messages through AVB tunnels. The obtained results verify that IEC 61850 event and sampled data may be reliably transported within the proposed framework with very low latency, even over a congested network. It is argued that since AVB streams can be flexibly configured from one or more central locations, and bandwidth reserved for their data ensuring predictability of delivery, this gives a solution which seems significantly more reliable than a pure MMS-based solution

DSL-based triple-play services

This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.

Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard

A Hybrid voice/text electronic mail system: an application of the integrated services digital network

The objective of this thesis is to present a useful application for the Integrated Services Digital Network (ISDN) that is expected to one day replace the analog phone system in use today. ISDN itself and its continuing evolution are detailed. The system developed as a part of this thesis involved the creation of an inexpensive phone terminal that can serve as an ISDN terminal and also as a bridge to a Local Area Network (LAN). The phone terminal provides a hybrid electronic mail system that allows the attachment of speech to text within a message. Messages created with this phone terminal could theoretically be sent locally using the LAN interface and globally using ISDN to other users with either phone terminals or multimedia personal computers. For this project, the two phone terminals created were interconnected via an Ethernet and using an 80486 PC to act as a Central Office System. This Central Office System provides speech/message storage for the phone terminals. It makes use of speech compression techniques to minimize the storage requirements. The speech compression techniques used as well as the field of speech coding in general are discussed

Implications of Implementing HDTV Over Digital Subscriber Line Networks

This thesis addresses the different challenges a telecommunications company would face when trying to implement an HDTV video service over a Digital Subscriber Line (DSL) connection. Each challenge is discussed in detail and a technology, protocol, or method is suggested to overcome that particular challenge. One of the biggest challenges is creating a network architecture that can provide enough bandwidth to support video over a network that was originally designed for voice traffic. The majority of the network connections to a customer premises in a telephony network consists of a copper pair. This type of connection is not optimal for high bandwidth services. This limitation can be overcome using Gigabit Ethernet (GE) over fiber in the core part of the network and VDSL2 in the access part of the network. For the purposes of this document, the core portion of the network is considered to be an area equal to several counties or approximately 50 miles in radius. The core network starts at the primary central office (CO) and spreads out to central offices in suburbs and small towns. The primary central office is a central point in the telecom operator\u27s network. Large trunks are propagated from the primary central office to smaller central offices making up the core network. The access portion of the network is considered to be an area within a suburb or small town from the central office to a subscriber\u27s home. Appendix A, located on page 60, contains a network diagram illustrating the scope of each of the different portions of the network. Considerations must also be given for the internal network to the residence such as category 5 (Cat5) cable or higher grade and network equipment that can provide up to 30 Megabits per second (Mbps) connections or throughput. The equipment in the telecommunications network also plays a part in meeting the challenge of 30 Mbps bandwidth. GE switches should be used with single mode fiber optic cable in the core part of the network. Digital Subscriber Line Access Multiplexers (DSLAM) with the capability to filter Internet Group Management Protocol (IGMP) messages should be used in the access part of the network to facilitate bandwidth utilization. Placement of this equipment and how the data is aggregated is another issue to consider when implementing HDTV service. Another major challenge facing the implementation of HDTV over DSL networks is controlling quality of service (QoS) throughout the network. Class of Service (CoS) and Differentiated Services (DiffServ) is a method of QoS that would enable video packets to have a higher priority and less delay than other data packets. The consumer could have data, video, and voice traffic all over the same DSL connection. Data, video and voice packets would need to have a different priority in order to maintain appropriate QoS levels for each service. The use of advanced technology in video encoding will be essential to the success of the video service. MPEG-2, MPEG-4, and Windows Media 9 are just a few of the video encoding technologies that could be used to reduce the necessary bandwidth for HDTV. The advancement of this technology is essential to allow telecommunications providers to offer HDTV. Another challenge for the telecom operator concerns the security of the network and service after implementation. Theft of service will be another area that the telecomm operator will be forced to resolve. The cable operators currently face this issue and lose millions of dollars in revenue. Authentication, IP filtering and MAC address blocking are a few possible solutions to this problem