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Design and testing of a centralized protection scheme for micro-grids

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Journal of Central South University 2015年第10期22卷 3876-3887页

作者： sohrab mirsaeidi Dalila Mat Said Mohammad Wazir Mustafa Mohammad Hafiz Habibuddin Kimia Ghaffari Centre of Electrical Energy Systems (CEES) Faculty of Electrical Engineering (FKE)Universiti Teknologi Malaysia (UTM) Young Researchers and Elites Club Saveh Branch Islamic Azad University

Micro-grids comprise low voltage distribution systems with distributed energy resources(DERs) and controllable loads which can operate connected to the medium voltage grid or islanded in a controlled coordinated way. This concept aims to move from "connect and forget" philosophy towards a full integration of DERs. Micro-grids can provide numerous economic and environmental benefits for end-customers, utilities and society. However, their implementation poses great technical challenges, such as a new philosophy in design of protection systems. In this work, a micro-grid protection scheme is presented based on positive-sequence component using phasor measurement units(PMUs) and a central protection unit(CPU). The salient feature of the proposed scheme in comparison with the previous works is that it has the ability to protect both radial and looped micro-grids against different types of faults with the capability of single-phase tripping. Furthermore, since the CPU is capable of updating its pickup values(upstream and downstream equivalent positive-sequence impedances of each line) after the first change in the micro-grid configuration(such as transferring from grid-connected to islanded mode and or disconnection of a line, bus, or DER either in grid-connected mode or in islanded mode), it can protect micro-grid against subsequent faults. Finally, in order to verify the effectiveness of the suggested scheme and the CPU, several simulations have been undertaken by using DIg SILENT Power Factory and MATLAB software packages.

关键词：中压电网保护方案设计理念 MATLAB软件包测试低压配电系统相量测量单元跳闸故障

Modeling and simulation of air-gapped current transformer based on Preisach Theory

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Protection and Control of Modern Power Systems 2017年第1期2卷 111-121页

作者： Ya Hui Wu Xin Zhou Dong sohrab mirsaeidi State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Current Transformer(CT)modeling,by which CT’s characteristics can be studied has a significant importance in CT selection and design.In spite of numerous studies about closed-core CT model,only a few works have been conducted on air-gapped ones with the following problems:models of which required data is easily-accessible,have poor simulations of magnetization process;on the contrary,models which have satisfactory simulations,are hard to be established because of the hard-to-get required data.Therefore,based on Preisach Theory,a novel air-gapped CT model is deduced from the closed core CT model.The proposed model is accurate and can be established easily.The saturation and remanence properties of closed-core CT and air-gapped CT are simulated and compared.

关键词： CT modeling Air gap Preisach Theory Saturation Remanence

Stability analysis of the Euler-Bernoulli beam with multi-delay controller

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Control Theory and Technology 2022年第3期20卷 338-348页

作者： Alireza Jalili Rahmtati Genqi Xu sohrab Effati Department of Mathematical Sciences Sharif University of TechnologyAzadi Ave.TehranIran Department of Mathematics Tianjin UniversityNankai DistrictTianjin300072China Department of Applied Mathematics Ferdowsi University of MashhadAzadi SquareMashhadIran

In this paper,we investigate the stabilization of an Euler-Bernoulli beam with time delays in the boundary controller.The boundary velocity feedback law is applied to obtain the closed-loop system.It is shown that this system generates a C_(0-)semigroup of linear operators.Moreover,the stability of the closed-loop system is discussed for different values of the controller constants and time delays via using spectral analysis and a suitable Lyapunov function.

关键词： Euler-Bernoulli beam Time delay Lyapunov method Spectral analysis

Reliability of trauma coding with ICD-10

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Chinese Journal of Traumatology 2022年第2期25卷 102-106页

作者： Farkhondeh Asadi Maryam Ahmadi Hosseini sohrab Almasi Department of Health Information Technology and Management School of Allied Medical SciencesShahid Beheshti University of Medical SciencesTehranIran

Purpose:The reliability of trauma coding is essential in establishing the reliable trauma data and adopting efficient control and monitoring policies.The present study aimed to determine the reliability of trauma coding in educational hospitals affiliated to Shahid Beheshti University of Medical Sciences,Iran.Methods:In this descriptive cross-sectional study,591 coded medical records with a trauma diagnosis in 2018 were selected and recoded by two coders.The reliability of trauma coding was calculated using Cohen's kappa.The data were recorded in a checklist,in which the validity of the content had been confirmed by experts.Results:The reliability of the coding related to the nature of trauma in research units was 0.75—0.77,indicating moderate reliability.Also,the reliability of the coding of external causes of trauma was 0.57—0.58,suggesting poor reliability.Conclusion:The reliability of trauma coding both in terms of the nature of trauma and the external causes of trauma does not have a good status in the research units.This can be due to the complex coding of trauma,poor documentation of the cases,and not studying the entire case.Therefore,holding training courses for coders,offering training on the accurate documentation to other service providers,and periodically auditing the medical coding are recommended.

关键词： Reliability Medical coding Trauma External causes of trauma

Smart Grid Communication Using Open Smart Grid Protocol

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Smart Grid Communication Using Open Smart Grid Protocol

The Structural Analysis of Driving Forces to Adaptive Capacity with Climate Change in Iranian Cities(Ahvaz City in Focus)

作者： Mazhar Hussain Ali Zohair Umar Saeed sohrab mirsaeidi Sijia Wang School of Electrical Engineering Beijing Jiaotong University

The smart grid transfers electricity from power utilities to the customers’ end using full-duplex digital communication technology and helps us to control the home appliances and factory machines to save electricity while reducing costs and increasing reliability and transparency. So, in order to ensure the grid reliability, we need to monitor and control the smart meters by means of data transfer and command signals on the single power line without using any other communication media to improve the cost-effectiveness of the proposed study. This paper proposes a hardware implementation of a Power Line Communication（PLC） protocol named Open Smart Grid Protocol（OSGP）. This protocol is based on the Open System Interconnection（OSI）model. The proposed system comprises monitoring and controlling server（Lap-top/Desktop）, power line communication modem, two PIC18 f4520 microcontrollers, one energy meter and power line as transmission media. This protocol is first implemented on a server in C-sharp by using the OSI model approach, and then on micro-controllers in order to control the energy meter. The power line communication modem is used to send and receive the data between the server and the energy meter. Finally, results are presented to validate the hardware implementation of the protocol.

关键词： C-Sharp Distribution System Microcontroller Modem Protocol Smart Meter Smart Grid

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Chinese Journal of Urban and Environmental Studies 2023年第4期11卷 46-71页

作者： Mostafa MOHAMMADI DEHCHESHMEH sohrab GHAEDI Fereshteh SHANBEHPOUR Department of Geography and Urban Planning Shahid Chamran University of Ahvaz

Climate change is an increasing concern for national and local governments around the world.The scope of the wide-ranging consequences of climate change has been shown in all aspects of human life and to different extents in cities and countries. Adaptation is the strategy agreed upon by the global community in facing climate change. This study aims to identify and structural modeling of driving forces of adaptation to climate change in the strategic city of Ahvaz, in southwest Iran. After identifying the factors and indicators through the study of records and a survey of the elite group, analysis and stratification were done using the combined interpretive structural modeling–decision-making trail and evaluation laboratory(ISM–DEMATEL) model. Finally, the main driving forces of adapting to climate change in Ahvaz were identified by Mic-Mac structural model. The research findings have shown among the five economic, social, institutional, physical, and technological factors, the economy has known as the most influential factor in adapting to climate change in Ahvaz. Also, among the 44 selected indicators, 10 driving forces were selected among them, and six driving forces, have economic and social backgrounds. Based on cross-impact analysis; the financial support for vulnerable groups, business improvement, alleviation of poverty measures, diversification of economic activities, social cohesion, and social trust in the government were recognized as the main drivers of Ahvaz city's adaptation to climate change.

关键词： Climate change adaptation cross-impact analysis Mic-Mac analysis Ahvaz

Investigation into engineering parameters of marls from Seydoon dam in Iran

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第5期9卷 912-923页

作者： sohrab Salehin Rock Mechanics Laboratory University of Tehran Tehran Iran

The quality of designed structures embedded in rocks is strongly related to rock strength parameters of intact rock.Measuring different parameters from tests could be very expensive in designing phase of projects.Estimating some parameters from other ones can reduce costs and time of project procedure.In this paper,the relationships between static and dynamic parameters of marls are studied by using the single and multiple linear regressions.For this purpose,several marl core samples from Seydoon region,Khoozestan Province in Iran are collected and tested.Some equations with sufficient correlation have been obtained to predict the engineering parameters of marls,especially the uniaxial compressive strength(UCS).

关键词： Marls Strength parameters Uniaxial compressive strength(UCS) Sonic wave velocity Brazilian tensile strength Triaxial test Point load test Index properties

Efficiency decomposition in parallel production systems with shared sources on interval data： An illustration of Iranian Banks

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International Journal of Biomathematics 2014年第5期7卷 229-235页

作者： sohrab Kordrostami Department of Mathematics Islamic Azad University Lahijan Branch Lahijan [ran

In real-world applications, some systems are composed of independent production units that use different inputs to produce outputs. The conventional data envelopment analysis model measures the relative efficiencies of a set of decision-making units with exact values of both inputs and outputs. In this paper, we propose an approach to assess parallel production systems with shared sources and bounded interval data, and also we provide a model that focuses on calculating the efficiency of the whole of a system along with the efficiencies of its components.

关键词：生产系统数据共享并行数据包络分析模型例证银行伊朗分解

Experimental Study of the Unsteady Actuation Effect on Induced Flow Characteristics in DBD Plasma Actuators

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Plasma Science and Technology 2015年第5期17卷 415-424页

作者： sohrab Gholamhosein POURYOUSSEFI Masoud MIRZAEI Department of Aerospace Engineering K N Toosi University of Technology

The main aim of this paper is to investigate unsteady actuation effects on the operation of dielectric barrier discharge （DBD） plasma actuators and to study induced flow characteristics of steady and unsteady actuators in quiescent air. The parameters affecting the operation of unsteady plasma actuators were experimentally measured and compared with the ones for steady actuators. The effects of excitation frequency and duty cycle on the induced flow pattern properties were studied by means of hot-wire anemometers, and the smoke visualization method was also used. It was observed that the current and the mean induced velocity linearly increase with increasing duty cycle while they are not sensitive to excitation frequency. Furthermore, with increasing excitation frequency, the magnitude of vortices shedding from the actuator decreases while their frequency increases. Nevertheless, when the excitation frequency grows beyond a certain level, the induced flow downstream of the actuator behaves as a steady flow. However, the results for steady actuators show that by increasing the applied voltage and carrier frequency, the velocity of the induced flow first increases and then decreases with actuator saturation and the onset of the emission of streaky glow discharge.

关键词： unsteady plasma actuator excitation frequency duty cycle induced flowpattern frequency response sequence