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  • 1.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Distance Protection of Transmission Lines with High Levels of Series Compensation: A study on frequency and time domain communication independent distance protection for series compensated lines2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Series capacitors are used in electric transmission lines to increase their power transfer capacity. They compensate for the inductive reactance of the line. They offer a useful alternative to building new lines, in view of economic and environmental constraints. However, during transmission line faults, the presence of series capacitors causes problems for distance protection relays. Distance protection is the most widely used protection method in transmission lines, due to its relatively simple working principle and its ability to work with only local measurements of voltage and current. As the number of series compensated transmission lines is increasing, and the typical compensation level is also increasing, it has become essential to investigate protection methods that can be employed in place of traditional distance protection in series compensated lines.

    This thesis addresses the problems associated with line protection in the presence of series capacitor compensation. The first part is an assessment of the performance of traditional distance relays in cases with high levels of series compensation. This was based both on simulation studies and on published works describing research studies and industry experience with series capacitor projects and the related line-protection issues. It is concluded that traditional distance protection cannot be used reliably with high levels of series compensation. The second part of the thesis describes some alternative protection methods that are developed and studied as candidates for better single-ended protection of series-compensated lines. These are based on incremental quantities, Lissajous curves and RL/RLC line models. These methods show positive results for single ended protection of series compensated lines.The incremental-quantity based method is fast and operates reliably, but faces under-reach problems with fault resistance. The Lissajous-curve basedmethod can be used as an alternative to the Fourier transform and has some advantages in overcoming inversion situations, but it requires at least a cycle of data to operate. The RL- and RLC-model based solutions can also operate fast, but lose accuracy with higher fault resistances. All the proposed protection methods are extensively tested, using data from fault test cases generated with PSCAD, and algorithms developed in Matlab.

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    kappa
  • 2.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    Hitachi Energy Research, Hitachi Energy, Västerås, Sweden.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    An Incremental Quantity Based Protection with Capacitor Voltage Estimation for Mid-Line Series Compensation2022Conference paper (Refereed)
    Abstract [en]

    Series capacitors are installed in transmission lines to increase power transfer capacity. However, their addition creates challenges for the line protection. Security and speed of phasor based protection schemes that work with local measurements (communication independent) are severely affected in the presence of series capacitors. Therefore, time-domain based protection methods may be considered as a potential solution for communication independent protection of series compensated lines. In this paper, an incremental quantity based protection scheme is presented for series compensated lines with the capacitor in the middle of the line. The method involves estimating the voltage across the capacitor bank, based on the current in the capacitor bank and metal oxide varistor during faults. Then this capacitor voltage estimation is used to implement the incremental quantity protection. The incremental quantity method consists of fault detection, phase selection, directional discrimination and distance estimation. A PSCAD model of a 500 kV, 200 km transmission line is used to simulate fault cases for evaluating the method. The proposed method is tested with different compensation levels, fault types, fault positions, inception angles, fault resistances and source impedance ratios. The results show that the proposed method can meet the dependability and security demands for the protection of series compensated lines.

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  • 3. Hasan, A. S. M. M.
    et al.
    Kabir, M. A.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Johansson, M. T.
    Thollander, P.
    Drivers and barriers to the implementation of biogas technologies in Bangladesh2022In: Biofuels, ISSN 1759-7269, E-ISSN 1759-7277, Vol. 13, no 5, p. 643-655Article in journal (Refereed)
    Abstract [en]

    In Bangladesh, despite available feedstock for producing biogas, the development of biogas production has been very slow. The objective of this research was to study the drivers for and barriers to biogas technology implementation in the country. As the research involved different types of stakeholders related to biogas production, the outcome provides clarity about the factors influencing the profusion of biogas production in Bangladesh. The outcome of the study identifies poor research and development, lack of coordination among stakeholders, an immature biogas market, lack of awareness and no feed-in tariff policy as the main barriers. In the case of drivers, the motivation of producing biogas as an efficient way of using waste, the availability of local experts, the attractiveness of a growing renewable energy market and the contribution of biogas technology in adaptation to climate change were found to be the most important factors. The study’s outcomes are found to be similar to other studies from developing countries with similar socio-economic status. In accordance with the important drivers and barriers identified in this study, recommendations for increasing the diffusion of biogas in Bangladesh are also presented at the end of the article.

  • 4.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    An Incremental Quantity Based Distance Protection with Capacitor Voltage Estimation for Series Compensated Transmission Lines2021In: IEEE Access, E-ISSN 2169-3536, Vol. 9, p. 164493-164502Article in journal (Refereed)
    Abstract [en]

    Series capacitors increase the power transfer limit of transmission lines. However, the protection of series compensated lines using only local measurement is challenging. Phasor based distance protection experiences delay and directional problems in the presence of a series capacitor. This paper presents an incremental quantity based distance protection algorithm for series compensated lines. The algorithm uses instantaneous voltage and current measurement from the local bus. It consists of capacitor voltage estimation, fault detection, phase selection, directional discrimination and distance estimation. The algorithm is extensively tested based on simulations with a line-end series capacitor, considering different source impedance ratios, fault inception angle, compensation levels, and fault resistance, location and type. This time-domain method is shown to work well, with fast decision time.

  • 5.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Distance Protection of Series Capacitor Compensated Lines: Practical Considerations, Industrial Status and Development2021In: Electricity, E-ISSN 2673-4826, Vol. 2, no 2, p. 168-186Article in journal (Refereed)
    Abstract [en]

    The introduction of series capacitors in transmission lines causes problems in terms of reliability and the security of distance protection relays. As distance protection is widely used in the transmission network, the challenge of applying it to series compensated lines has been taken up by utilities and relay manufacturers in various ways. In the field of power system protection, developments are largely driven by relay manufacturers, and are often not published in the academic literature; the status and trend of the relay manufacturer’s development are better found in their product manuals and patent activity. Further insight into specific implementations by transmission utilities can be found from publications in industry-led forums and some academic journals. This article surveys the status and development of distance protection for series compensated lines, with a focus on industrial implementation and practical considerations. Factors that influence the protection of series compensated lines are presented. Implementation examples reported by utilities are summarized as examples of the different situations encountered and the methods used to deal with them. It is observed that many utilities use communication-aided protection in series compensated lines, and distance protection is used with reduced reach. Solutions described in relay manuals are presented to demonstrate the manufacturers’ approaches to problems associated with series capacitor protection. While there are methods to counter voltage inversion, current inversion seems to represent a more serious challenge. A patent overview indicates the trends in this domain to be moving towards time-domain-based faster protection methods.

  • 6.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Fault test cases for series compensated transmission line with capacitor at line terminal2021Data set
    Abstract [en]

    This data set contains time series data of different simulated fault cases in high voltage series compensated transmission lines. The simulation is done in PSCAD using the Python automation library. The capacitor is located at one of the line terminals with CT and VT. The modelled line is 500 kV and 200 km long. The simulation is run for 1 second with 10 kHz sampling rate. 

    Each file contains 7 data in the following order, 

    Time, Voltage phase A, Voltage phase B, Voltage phase C, Current phase A, Current phase B, Current phase C.

    The variables used to study different test cases are shown below,

    Fault inception angle (phase A): 0 and 90 degreeSource impedance ratio: 0.20 and 0.35Capacitor level: 94 µF(50%), 78 µF(60%), 67 µF(70%)Fault resistance: 0.10, 10, 20, 30 ohmFault location: 10 km reverse, 10 km, 50 km, 100 km, 125 km, 150 km, 155 km, 160 km. 165 km, 170 km, 180 km, 190 kmFault type: No-fault, AG, BG, CG, ABG, CAG, BCG, ABCG, AB, CA, BC, ABC

    All these factors lead to 6912 test cases in total. The test cases are organized in four (4) zipped folders each containing 1728 test cases. The PSCAD model file and an example python script that can be used to automate the simulations are also included herewith for anyone interested to replicate the results. 

  • 7.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Fault test cases for series compensated transmission line with the capacitor at the middle of the line2021Data set
    Abstract [en]

    This data set contains time series data of different simulated fault cases in high voltage series compensated transmission lines. The simulation is done in PSCAD using the Python automation library. The capacitor is located in the middle of the line. The model of the line is given in the attached pdf file. The CT and VT are located at bus S. The distance are counted from bus S. The modelled line is 500 kV and 200 km long. The simulation is run for 1 second with 10 kHz sampling rate. 

    Each file contains 10 data in the following order, 

    Time, Voltage phase A, Voltage phase B, Voltage phase C, Current phase A, Current phase B, Current phase C, Voltage across capacitor phase A, Voltage across capacitor phase B, Voltage across capacitor phase C.

    The variables used to study different test cases are shown below,

    Fault inception angle (referred to phase A voltage): 0 and 90 degreeSource impedance ratio: 0.20 and 0.35Capacitor compensation level: 94 µF(50%), 78 µF(60%), 67 µF(70%)Fault resistance: 0.10, 10, 20 ohmFault location: 10 km, 30 km, 50, 70 km, 90 km, 95 km, 105 km, 110 km, 130 km, 150 km, 160 km, 170 km, 180 kmFault type: No-fault, AG, BG, CG, ABG, CAG, BCG, ABCG, AB, CA, BC, ABC

    All these factors lead to 5616 test cases in total. The test cases are organized in four (4) zipped folders each containing 1404 test cases. The PSCAD model file and an example python script that can be used to automate the simulations are also included herewith for anyone interested to replicate the results. 

  • 8.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    ABB Power Grids Sweden AB, Power Grids Research, Västerås 722 26, Sweden.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Review of recent developments in distance protection of series capacitor compensated lines2021In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 190, article id 106831Article in journal (Refereed)
    Abstract [en]

    Introduction of series capacitors in transmission lines can cause problems with reliability and security of distance protection, due to problems such as current inversion, voltage inversion and sub-synchronous oscillation. Distance protection is widely used for transmission lines and has desirable features not available from traditional alternatives, which has motivated attempts to adapt it to work better with series capacitors. Research and development in overcoming the challenges using distance protection in series compensated lines have also been actively pursued during this period. Thus there is a need to summarize and systematically categorize developments, to show recent trends and highlight further research opportunities. This paper aims to fill that gap by a thorough literature survey of distance protection of series compensated lines, including a clear background of the problems that need to be solved. The scope of this work is limited to distance protection schemes that work with local measurements only. It is observed that the developments in this domain are largely concentrated on voltage drop estimation across capacitor bank, phasor estimation and adaptive protection schemes. This work will provide an overview of the latest developments for experienced researchers and will be a reference for new researchers interested in this domain.

  • 9.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Impact of High Levels of Series Compensation on Line Distance Protection2020In: IET Conference Publications, 2020Conference paper (Refereed)
    Abstract [en]

    Series compensation of transmission lines creates several challenges for distance protection, particularly at the high compensation levels that have recently become more common. In this paper, the effect of high levels of series compensation on distance protection is evaluated, using a PSCAD simulation model of a 500 kV, 200 km transmission line with a series capacitor bank. The capacitor bank model includes overvoltage protection using a metal oxide varistor (MOV) and bypass circuit breaker. Compensation levels of 70%, 100% and 140% are simulated and phase to ground faults are simulated at several positions along the line, with fault resistance of 0 Ω and 30 Ω and fault inception angle of 0 ° and 90 °. It is observed from the simulation results that traditional distance protection experiences severe challenges at high levels of series compensation. With increasing compensation level, an increased length of line experiences voltage inversion and current inversion during a fault. The fault trajectories in the R-X plane show that voltage and current inversion during a fault can cause directional problems and delay for the distance relay. Sub-synchronous oscillation (SSO) is observed for faults in series compensated lines, causing over-reach and under-reach problems as well as delayed relay operation.

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    Impact of High Levels of Series Compensation on Line Distance Protection
  • 10.
    Habib, Md Zakaria
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Impact of the fault location methods on SAIDI of a resonant-earthed distribution system2020In: 2020 IEEE International Conference on Power Systems Technology, POWERCON 2020, Institute of Electrical and Electronics Engineers Inc. , 2020Conference paper (Refereed)
    Abstract [en]

    Reliability indices of a distribution system can be improved by reducing failure rate and restoration time. A resonant-earthed distribution system has a low failure rate because numerous transient faults become self-extinguishing. However, in such networks, it can be difficult and time-consuming to locate nontransient faults resulting in aggravating the restoration time. This paper analyzes how different fault location methods affect the restoration time and SAIDI. Two major fault location methods are modeled for the calculation of the reliability indices and then applied to a radial feeder of a medium-voltage distribution system. The results show that SAIDI varies depending on the applied fault location method and its accuracy. The influence of fault location methods on labour costs is also discussed.

  • 11. Khan, MD S. A.
    et al.
    Hoq, Md Tanbhir
    Department of Electrical and Electronic Engineering, University of Asia Pacifi.
    Karim, A. H. M. Zadidul
    Alam, Md Khairul
    Howlader, Masum
    Rajkumar, Rajprasad Kumar
    Energy Harvesting- A Technical Analysis of Evolution, Control Strategies and Future Aspects2019In: Journal of Electronic Science and Technology, ISSN 1674-862X, Vol. 17, no 2, p. 116-125Article in journal (Refereed)
    Abstract [en]

    This paper provides a tech nical analysisof energy harvesting, including different aspects ofharvesting energy, individual case history, controlstrategies of harvesting in each energy sector togetherwith the current trend and future aspects of it. Energyharvesting is comparativ ely a new concept which isgrowing very fast since the 20th century and catchingn ew generation research approach . The paper not onlydescribes the past and current scenarios of harvestingenergy with radio frequency and renewables but alsogives author’s own anticipation of the upcoming futuretrends of it comparing the case histories .

  • 12.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Habib, Md Zakaria
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Reliability Assessment of Protection Schemes for Series Compensated Transmission Lines2019In: 4th International Conference on System Reliability and Safety (ICSRS), Rome, Italy, Institute of Electrical and Electronics Engineers (IEEE) , 2019Conference paper (Refereed)
    Abstract [en]

    Series capacitors are used in transmission lines for enhancing power transmission limit. However, they complicate the line’s protection due to impedance change of the line, voltage inversion, current inversion and sub-synchronous oscillation. Distance and differential protections are used in different arrangements in transmission line protection. Often they are used together as main and backup protection. In this paper, the fault tree method is used to compare the reliability of three common transmission line protection schemes. The schemes considered here are distance (main)-distance (backup)(Z; Z), differential (main)-distance (backup) (delta;Z) and differential (main)-differential (backup) (delta;delta). Fault trees are used to calculate the reliability of protection schemes in terms of both unavailability and failure rate. The analyses show that, for series compensated lines, using distance protection reduces protection system reliability. Differential protection performs best in terms of reliability despite depending entirely on communication.

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    Reliability Assessment of Protection Schemes for Series Compensated Transmission Lines
  • 13.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    The Impact of Current Inversion on Line Protection in High Voltage Transmission Lines with Series Compensation2019Conference paper (Refereed)
    Abstract [en]

    Series capacitors are used in some transmission lines to raise the power transfer limit. If a fault occurs at a location behind which the total reactance is capacitive, the result is current inversion, also known as current reversal. In a current inversion, current leads the voltage instead of lagging it. The probability of current inversion increases with higher levels of compensation. In this paper, the effect of current inversion is studied in distance and differential protection of transmission lines. A 500 kV transmission line is modelled, with compensation levels of 70%, 100% and 140%. Phase to ground faults are applied with fault inception angles of 0, 60 and 90. It is shown that current inversion can cause serious problems with distance protection. Differential protection is not severely affected by current inversion. The protection schemes are significantly influenced by parameters of the capacitor bank overvoltage protection components, particularly the metal-oxide varistor.

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    The Impact of Current Inversion on Line Protection in High Voltage Transmission Lines with Series Compensation
  • 14.
    Howlader, Masum
    et al.
    University of Asia Pacific.
    Saif, Aziz un Nur Ibn
    University College Dublin.
    Khan, MD Shahrukh Adnan
    University of Asia Pacific.
    Howlader, Md. Mahfuz
    University of Dhaka.
    Rokonuzzaman, Md
    University of Asia Pacific.
    Hoq, Md Tanbhir
    u1nhhq10.
    Approach for Grid Connected PV Management: Advance Solar Prediction and Enhancement of Voltage Stability Margin using FACTs Device2018Conference paper (Refereed)
    Abstract [en]

    The uncertainty in solar energy is different from conventional, dispatchable generation fuels and can be difficult to incorporate into standard system operating procedures. We are moving towards a time where people will be generating energy by themselves from solar on their rooftops that would significantly increase utilities’ solar share of energy sources. This essentially paves the way for a huge ramp rate which could destabilize the local electricity grid. It becomes imperative for utilities and control system operators to modify their planning, scheduling, and operating strategies to accurately account this variability nature of solar resources as well as keeping the existing standards of reliability. In this work machine learning algorithm is used to train models on solar irradiance data and different meteorological weather information’s to predict solar irradiance for different cities to validate the model. This report also puts an in-depth analysis with regard to the challenges of solar resources with the integrating ,planning, operation and particularly the stability of the rest of the power grid, including existing generation resources, customer requirements and the transmission system itself that will lead to improved decision making in resource allocations and grid stability.

  • 15.
    Hoq, Md Tanbhir
    et al.
    University of Asia Pacific.
    Murad, Mohammed Ahsan Adib
    University College Dublin.
    Rokonuzzaman, Mohammad
    Hossain, Nusrat
    Assessing Impact of Large Scale Integration of Wind and Solar PV Power Generation on Small Signal and Transient Stability2018In: 4th International Conference on Electrical Engineering and Information & Communication Technology (iCEEiCT), IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    One imperative challenge in building a sustainable electricity future is to integrate renewable energy sources in the present energy mix. Renewable energy sources are inherently different in nature from their conventional counterparts. Thus integration to existing system posses a substantial challenges. In this paper using a IEEE 14 bus test system the effect of large scale and distributed integration of wind and solar PV on power system stability is assessed using PSAT. Both small signal and transient stability are studied with varying amount of renewable energy in the system. From the simulation results, it is observed that the small signal stability degrades with higher renewable energy penetration, and the transient frequency and voltage response of the system worsens as well with higher renewable energy in the system, but nonetheless the systems in different scenarios remains stable despite having poor damping.

  • 16.
    Hasan, ASM Monjurul
    et al.
    Bangladesh Army International University of Science and Technology.
    Hoq, Md Tanbhir
    University of Asia Pacific.
    Thollander, Patrik
    Linköping University.
    Energy management practices in Bangladesh’s iron and steel industries2018In: Energy strategy reviews, ISSN 2211-467X, Vol. 22, p. 230-236Article in journal (Refereed)
    Abstract [en]

    The aim of this paper was to study energy management and improved energy efficiency among large iron and steel mills in Bangladesh. The results show that there are some barriers to energy management practices among large steel mills, the most important barriers being the perceived absence of cost-effective technical measures, high perceived risks due to uncertain future energy costs and poor information quality. However, this study has shown that the reduction in energy costs due to improved energy efficiency constitutes the most important driver for energy efficiency in the studied steel mills. The results also show that most of the steel mills have not had any technical energy efficiency improvement measures implemented in the production process. Moreover, the steel mills seem unfamiliar with the concept of including energy service companies, and the lack of information or awareness seems to be the main reason behind this. The paper also finds that energy efficiency is perceived to be able to be improved by 6%–8% through energy management practices.

  • 17. Hoq, Md Tanbhir
    et al.
    Hasan, ASM Monjurul
    Kabir, Md Ahsan
    Sakib, Taiyeb Hasan
    Renewable energy potential assessment for electricity production in Hatiya Island Bangladesh2018Conference paper (Refereed)
    Abstract [en]

    Hatiya Island in Bangladesh is an off grid remote locality. Despite being only twenty kilometers away from shore the island lacks any electricity grid connection. There has been governmental initiative for establishing a hybrid power plant in the island but that project was not realized. Thus there is a need for further investigation to plan electricity production in the island to sustain its energy requirements and development. As a part of a project to identify, model and optimize electricity production in the island this paper investigates the renewable energy potential for power generation in the island. It is found that the island has substantial potential for solar and biomass power generation and further investigation is required to understand the reality of wind power generation. Simulation with HOMER is conducted to outline possible energy mix for the island. There is no data found for electric energy requirement of the island and therefore further research is suggested to mitigate the discrepancies found in the existing literature build a concrete model for calculating optimum energy mix.

  • 18. Hasan, A S M Monjurul
    et al.
    Hoq, Md Tanbhir
    Kabir, Ahsan
    Sakib, Taiyeb
    The Cost Factor Analysis of Wind Power Plants-An Economic Perspective2018Conference paper (Refereed)
    Abstract [en]

    Renewable energy can help the countries to meet their sustainable development goals. It provides provision of access to clean, secure, reliable and affordable energy. Renewable energy has gone mainstream, accounting for the majority of capacity additions in power generation today. Today wind power plant technologies are experiencing renaissance and the wind turbine promises to be an important alternative to fossil fuels in the future. Therefore, cost factors of the wind power plants have been analyzed in this paper in perspective of Sweden and Germany. The capital expenditure costs include material and labour cost for civil work, turbine installation and electrical connection. The most significant part among all is turbine installation. The revenue depends on the market price and financial support through government strategies and regulations. The analysis is based on a range of data sources of cost indicators – capital expenditure, operational expenditure, levelised cost of electricity and revenue. This paper is not a detailed financial analysis of project economics rather it provides simple and reliable information which can be used to evaluate the costs of different wind power projects.

  • 19.
    Ghorbani, Hossein
    et al.
    ABB AB, High Voltage Cables, Karlskrona, Sweden.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Edin, Hans
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Effect of heat treatment on morphology and dielectric properties of PE cable insulation material2015In: No 24 (2015): Proceedings of the 24th Nordic Insulation Symposium, 2015Conference paper (Refereed)
    Abstract [en]

    It is known that the heat treatment process in theproduction of extruded cables, affects the electricalproperties of polymeric insulation materials; this effectis via two main phenomena; first, it leads to diffusionand removal of polar substances from the system;second, it affects the polymer morphology by increasingthe polymer chain relaxation and creation of crystallites,hence increasing the crystallinity of the material.In this study, thick pressed samples with additive freelow density polyethylene (LDPE) insulation materialwere heat treated at different conditions for differentperiods of times. Differential scanning calorimetry(DSC) measurements confirmed that heat treatmentleads to higher crystallinity and higher lamella thicknessin LDPE. Dielectric properties of the material wasstudied by conduction current measurement anddielectric spectroscopy.Conduction current of samples with different heattreatment times was measured at high electric fieldswhich shows that the conduction current of LDPE isaffected by heat treatment. Generally, the apparentconductivity decreases by heat treatment.Dielectric spectroscopy measurements show that heattreatment does not have a significant effect on real andimaginary permittivity of the polymer. Interestingly, anincrease in the sample thickness via heat treatment, wasobserved both by sample thickness related to thememory effects in the polymer which needs to be takeninto consideration for accurate capacitancemeasurements.

  • 20.
    Hoq, Md Tanbhir
    et al.
    Islamic University of Technology.
    Nawshad, Uddin Ahmed
    Islamic University of Technology.
    Islam, Nizamul
    Islamic University of Technology.
    Ibnea, Sina
    Islamic University of Technology.
    Syfullah, Khaled
    Islamic University of Technology.
    Rahman, Raiyan
    Islamic University of Technology.
    Micro hydro power: promising solution for off-grid renewable energy source2011In: International Journal of Scientific & Engineering Research, ISSN 2229-5518, Vol. 2, no 12, p. 1-5Article in journal (Refereed)
    Abstract [en]

    Hydro power is one of the oldest sources of energy used by human civilization. It has been used hundreds of years ago to turn waterwheels for different purposes such as grind-ing grains, sawing logs and manufacturing cloths. Large scale hydroelectric power plants have been being used for generat-ing electricity worldwide from the last century. There are many types of hydropower plant such as dam-reservoir base power plant, ocean tidal power plant, wave power plant and others. In this paper the use and possibility of micro water current turbine is discussed. This type of power production uses the flow of a stream to generate electricity. It does not require dam or reservoir, it only uses the free flowing water from a river or canal or any other streams. They are usually used for meeting small local demand like lighting, charging batteries and other small home appliances. They are cheap and small, and the developing countries may manufacture and im-plement this scheme to help supply the needed electricity to small communities in remote areas such as island formed in river bed. They can produce electricity if the water flow veloc-ity is greater than .5 m/s.

  • 21.
    Kawser, Mohammad T
    et al.
    Department of Electrical and Electronic Engineering, Islamic University of Technology, Dhaka, Bangladesh.
    Syfullah, Md K
    Department of Electrical and Electronic Engineering, Islamic University of Technology, Dhaka, Bangladesh.
    Chowdhury, Nawshad UA
    Department of Electrical and Electronic Engineering, Islamic University of Technology, Dhaka, Bangladesh.
    Hoq, Md Tanbhir
    Department of Electrical and Electronic Engineering, Islamic University of Technology, Dhaka, Bangladesh.
    Performance Comparison among MIMO Techniques at Different Interference Levels for LTE2011In: Communication and Networking: International Conference, FGCN 2011, Held as Part of the Future Generation Information Technology Conference, FGIT 2011, in Conjunction with GDC 2011, Jeju Island, Korea, December 8-10, 2011. Proceedings, Part I, 2011, p. 103-110Conference paper (Refereed)
    Abstract [en]

    MIMO technique (multi antenna transmission and reception) is a keyfeature of long term evolution (LTE) which ensures higher spectral efficiencyand better multiuser flexibility making a cellular system spectrally efficient butinherently densely populated and interference-limited. Performance of spatialmultiplexing MIMO techniques degrades with the introduction of interferencein the system. To choose optimum MIMO mode it is worthwhile to analyze theUE (user equipment) throughput under different interference scenarios beforephysical implementation of a system. This paper contains a comparative studyof MIMO technique performances in terms of UE throughput under twodifferent UE speeds and interference scenarios.

  • 22.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Assessing Distance Protection Methods for Series Compensated Transmission LinesManuscript (preprint) (Other academic)
    Abstract [en]

    Series capacitors create challenges for traditional phasor-based distance relays in power transmission lines. Phasor based distance relays experience directional problems and delays.This paper compares the performance of phasor-based distance protection in series compensated line protection with three other distance protection methods. The first method is based on incremental quantities in the time domain, the second is based on Lissajous curves and conic section general equation, and the third is based on the RL and RLC model of the transmission line.The performance of these methods is evaluated in different fault conditions that create problems for phasor-based distance protection.Their relative advantages and disadvantages are outlined and discussed to identify their suitability for series compensated line protection. It is observed that the incremental quantity and model-based protections give fast and secure protection in series compensated lines. The conic section general equation based method can help avoid inversion, but the operating speed is slower than the other methods.

  • 23.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Distance Protection of Series Compensated Transmission Line using Lissajous Curves and Conic Section General EquationManuscript (preprint) (Other academic)
    Abstract [en]

    We demonstrate a time-domain estimation of impedance, based on the conic-section general equation and Lissajous curves, applied to protection of transmission lines that have series-capacitor compensation. This method helps to avoid the problems experienced by phasor-based distance relays when series compensation leads to voltage inversion or current inversion. Validation is performed using data from simulations of series compensated lines with a wide range of parameters such as sampling frequency, source impedance ratio, compensation level, fault inception angle,fault resistance, and fault location. It is seen that this method works well for series compensated lines, with operating times in the range of one and a half cycles.

  • 24.
    Hoq, Md Tanbhir
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Wang, Jianping
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Time Domain Distance Protection for Series Compensated Transmission Lines  Using RL and RLC Line ModelsManuscript (preprint) (Other academic)
    Abstract [en]

    Fast time-domain distance protection using RL and RLC models of a transmission line is presented in this paper for application to series compensated transmission lines. The proposed method is suited to both line-terminal andmid-line series compensation. It avoids classic limitations of delays and directional problems that phasor-based distance protection exhibits in series compensated transmission lines in the presence of voltage or current inversion sand subsynchronous oscillations. The method is validated with different system parameters such as compensation levels, source impedance ratio, fault inception angle, and fault resistance. The proposed method works well, with operating times in the range of a half cycle.

1 - 24 of 24
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