7,686 research outputs found
Performance evaluation of secondary control policies with respect to digital communications properties in inverter-based islanded microgrids
A key challenge for inverted-based microgrids working in islanded mode is to maintain their own frequency and voltage to a certain reference values while regulating the active and reactive power among distributed generators and loads. The implementation of frequency and voltage restoration control policies often requires the use of a digital communication network for real-time data exchange (tertiary control covers the coordi- nated operation of the microgrid and the host grid). Whenever a digital network is placed within the loop, the operation of the secondary control may be affected by the inherent properties of the communication technology. This paper analyses the effect that properties like transmission intervals and message dropouts have for four existing representative approaches to secondary control in a scalable islanded microgrid. The simulated results reveals pros and cons for each approach, and identifies threats that properly avoided or handled in advance can prevent failures that otherwise would occur. Selected experimental results on a low- scale laboratory microgrid corroborate the conclusions extracted from the simulation study.Peer ReviewedPostprint (author's final draft
Evaluation of Time-Critical Communications for IEC 61850-Substation Network Architecture
Present-day developments, in electrical power transmission and distribution,
require considerations of the status quo. In other meaning, international
regulations enforce increasing of reliability and reducing of environment
impact, correspondingly they motivate developing of dependable systems. Power
grids especially intelligent (smart grids) ones become industrial solutions
that follow standardized development. The International standardization, in the
field of power transmission and distribution, improve technology influences.
The rise of dedicated standards for SAS (Substation Automation Systems)
communications, such as the leading International Electro-technical Commission
standard IEC 61850, enforces modern technological trends in this field. Within
this standard, a constraint of low ETE (End-to-End) latency should be
respected, and time-critical status transmission must be achieved. This
experimental study emphasis on IEC 61850 SAS communication standard, e.g. IEC
61850 GOOSE (Generic Object Oriented Substation Events), to implement an
investigational method to determine the protection communication delay. This
method observes GOOSE behaviour by adopting monitoring and analysis
capabilities. It is observed by using network test equipment, i.e. SPAN (Switch
Port Analyser) and TAP (Test Access Point) devices, with on-the-shelf available
hardware and software solutions
Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)
An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined
Internet of Things-aided Smart Grid: Technologies, Architectures, Applications, Prototypes, and Future Research Directions
Traditional power grids are being transformed into Smart Grids (SGs) to
address the issues in existing power system due to uni-directional information
flow, energy wastage, growing energy demand, reliability and security. SGs
offer bi-directional energy flow between service providers and consumers,
involving power generation, transmission, distribution and utilization systems.
SGs employ various devices for the monitoring, analysis and control of the
grid, deployed at power plants, distribution centers and in consumers' premises
in a very large number. Hence, an SG requires connectivity, automation and the
tracking of such devices. This is achieved with the help of Internet of Things
(IoT). IoT helps SG systems to support various network functions throughout the
generation, transmission, distribution and consumption of energy by
incorporating IoT devices (such as sensors, actuators and smart meters), as
well as by providing the connectivity, automation and tracking for such
devices. In this paper, we provide a comprehensive survey on IoT-aided SG
systems, which includes the existing architectures, applications and prototypes
of IoT-aided SG systems. This survey also highlights the open issues,
challenges and future research directions for IoT-aided SG systems
Time-efficient fault detection and diagnosis system for analog circuits
Time-efficient fault analysis and diagnosis of analog circuits are the most important prerequisites to achieve online health monitoring of electronic equipments, which are involving continuing challenges of ultra-large-scale integration, component tolerance, limited test points but multiple faults. This work reports an FPGA (field programmable gate array)-based analog fault diagnostic system by applying two-dimensional information fusion, two-port network analysis and interval math theory. The proposed system has three advantages over traditional ones. First, it possesses high processing speed and smart circuit size as the embedded algorithms execute parallel on FPGA. Second, the hardware structure has a good compatibility with other diagnostic algorithms. Third, the equipped Ethernet interface enhances its flexibility for remote monitoring and controlling. The experimental results obtained from two realistic example circuits indicate that the proposed methodology had yielded competitive performance in both diagnosis accuracy and time-effectiveness, with about 96% accuracy while within 60 ms computational time.Peer reviewedFinal Published versio
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