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Nano-structured photovoltaic cell design for high conversion efficiency by optimizing various parameters

- Shelat, Niraj, Das, Narottam, Khan, Masud, Islam, Syed

  • Authors: Shelat, Niraj , Das, Narottam , Khan, Masud , Islam, Syed
  • Date: 2019
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2019 29th Australasian Universities Power Engineering Conference; Momi Bay, Fiji; 26th-29th November 2019
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  • Description: This paper investigates the effect of different types of nano-grating structures embossed on top of the substrate of solar photovoltaic (PV) cell for high conversion efficiency. The simulation results for light reflection are obtained by using Opti-wave finite difference time-domain (Opti-FDTD) software. These nano-grating structures have different shapes, such as triangular, trapezoidal, pillar and parabolic. These nano-grating profiles work as a multilayer anti-reflective coating for GaAs solar cells and reduce the light reflection from the surface of the panel and increase the light trapping capacity inside the solar cell. These structures allow the gradual change in refractive index and provide a high transmission and less reflection of light that confirms excellent anti-reflective coating and increased light trapping capacity inside the cell substrate. For this simulation, different periodic shaped arrangements were made to obtain the higher conversion efficiency, the factors considered while develop the design are the aspect ratio (AR), thickness of the nano-grating structure and duty cycles. The simulation result shows that the light reflection loss in pillar shaped nano-grating structures having 150 nm of height and a 50% period (i.e., duty cycle) is ~0.5% only, which is the lowest reflection loss obtained, when compared with the triangular and trapezoidal shaped nano-grating structures, it is approximately 38% more efficient in trapping the incident light.
  • Description: This research is supported by the School of Engineering and Technology, Melbourne, Victoria; Centre for Intelligent Systems, Brisbane, QLD, Central Queensland University, Australia.

A comprehensive analyses of aging characteristics of oil-paper insulation system in HVDC converter transformers

- Cui, Huize, Yang, Liuqing, Zhu, Yuanwei, Li, Shengtao, Abu-Siada, A., Islam, Syed

  • Authors: Cui, Huize , Yang, Liuqing , Zhu, Yuanwei , Li, Shengtao , Abu-Siada, A. , Islam, Syed
  • Date: 2020
  • Type: Text , Journal article
  • Relation: IEEE Transactions on Dielectrics and Electrical Insulation Vol. 27, no. 5 (2020), p. 1707-1714
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  • Description: This paper investigates the dissolved gases evolution in transformer oil under combined DC/AC electrical-Thermal stress. Dissolved gases detected in transformer aged insulation oil reveal that oil under AC electric field combined with thermal stress can produce more dissolved gases than oil under DC electric field with thermal stress but less than the gases produced in oil under distorted AC or combined AC/DC voltage stress. This is attributed to the divergent migration properties of the charged components under different types of electric fields. To further understand this behavior, carrier recombination coefficient is proposed to explain the oil DGA results under various aging stresses. Results show that diagnostic parameters such as breakdown voltage, oil interfacial tension, and moisture content in pressboard should be used along with DGA results in order to accurately diagnose the insulation condition within converter transformers that impose a combined AC/DC voltage stress on the insulation system. © 1994-2012 IEEE.
  • Description: This work has been supported by the National Key Research and Development Program of China (2017YFB0902705), State Key Laboratory of Electrical Insulation and Power Equipment (EIPE20210), the National Natural Science Foundation of China (51907148), the Youth Fund of State Key Laboratory of Electrical Insulation and Power Equipment (EIPE19308), the Foundation Project of State Grid in Shaanxi province section, China (SGSNKY00SPJS1900302). The authors thank the Natural Science Basic Research Plan in Shaanxi Province of China (2019JQ-070).

Trustworthiness of self-driving vehicles for intelligent transportation systems in industry applications

- Chowdhury, Abdullahi, Karmakar, Gour, Kamruzzaman, Joarder, Islam, Syed

  • Authors: Chowdhury, Abdullahi , Karmakar, Gour , Kamruzzaman, Joarder , Islam, Syed
  • Date: 2021
  • Type: Text , Journal article
  • Relation: IEEE Transactions on Industrial Informatics Vol. 17, no. 2 (2021), p. 961-970
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  • Description: To enhance industrial production and automation, rapid and faster transportation of raw materials and finished products to and from distributed factories, warehouses and outlets are essential. To reduce cost with increased efficiency, this will increasingly see the use of connected and self-driving commercial vehicles fitted with industrial grade sensors on roads, shared with normal and self-driving passenger vehicles. For its wide adoption, the trustworthiness of self-driving vehicles in the intelligent transportation system (ITS) is pivotal. In this article, we introduce a novel model to measure the overall trustworthiness of a self-driving vehicle considering on-Board unit (OBU) components, GPS data and safety messages. In calculating the trustworthiness of individual OBU components, CertainLogic and beta distribution function (BDF) are used. Those trust values are fused using both the dempster-Shafer Theory (DST) and a logical operator of CertainLogic. Results of our simulation show that our proposed method can effectively determine the trust of self-driving vehicles. © 2005-2012 IEEE.

Multi-agent based autonomous control of microgrid

- Shawon, Mohammad Hasanuzzaman, Ghosh, Arimdam, Muyeen, S., Baptista, Murilo, Islam, Syed

  • Authors: Shawon, Mohammad Hasanuzzaman , Ghosh, Arimdam , Muyeen, S. , Baptista, Murilo , Islam, Syed
  • Date: 2020
  • Type: Text , Conference proceedings
  • Relation: 2nd International Conference on Smart Power and Internet Energy Systems, SPIES 2020, 15-18 Sept. 2020, Bangkok, Thailand p. 333-338
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  • Description: Microgrid (MG), a revolutionary concept in the energy infrastructure, plays an important role for the establishment of a resilient grid infrastructure. Since its emergence, it has evolved around a number of cutting edge technologies for its smooth operation and control. Among them multi-agent system (MAS) provides an intelligent and decentralized platform for the control of microgrid. This paper highlights the application of a MAS in an AC microgrid, including a detailed structure of microgrid, the communication interface between microgrid and multi-agent platform. A detailed small scale microgrid model has been simulated in MATLAB/SIMULINK environment, whereas the agent platform has been implemented in JADE (Java Agent Development Framework) platform. The MAS autonomously detects main grid outage and facilitates seamless transition from grid-connected mode to islanding mode; thus ensures overall smooth operation of the power network. Simulation results are presented to verify the effectiveness of the MAS based control system. © 2020 IEEE.

Disconnection of single-phase rooftop PVs after short-circuit faults in residential feeders

- Yengejeh, Hadi, Shahnia, Farhad, Islam, Syed

  • Authors: Yengejeh, Hadi , Shahnia, Farhad , Islam, Syed
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Australian Journal of Electrical and Electronics Engineering Vol. 13, no. 2 (2016), p. 151-165
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  • Description: This paper presents an analysis on the disconnection time of single-phase rooftop photovoltaic systems (PVs), located in a three-phase four-wire low voltage distribution feeder, after a single-phase and a three-phase short-circuit fault on the low-voltage feeder. The paper aims to evaluate and discuss the disconnection time and disconnection sequence of PVs in a network with 100% PV penetration level to evaluate the islanding issues that are related to the safety of people and the damage of electrical apparatus. The impact of different parameters such as the location of the fault, impedance of the fault and the ratio of PVs generation capacity to the load demand are contemplated in the analysis. Furthermore, the influence of the network earthing in the form of multiple earthed neutral and non-effectively grounded systems are evaluated on the PVs disconnection time. This research intends to figure out the conditions under which the PVs in the feeder may fail to disconnect after a single-phase or three-phase fault and continue to feed the fault.

Impact of PEV charging and rooftop PV penetration on distribution transformer life

- Geiles, Tristan, Islam, Syed

  • Authors: Geiles, Tristan , Islam, Syed
  • Date: 2013
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2013 IEEE Power and Energy Society General Meeting, PES 2013; Vancouver, Canada; 21st-25th July 2013 p. 1-5
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  • Description: As Plug-in Electric Vehicles (PEVs) take a greater share in the automobile market; their penetration levels may bring potential challenges to the electric utility especially at the distribution level. However with increasing penetration of rooftop photovoltaics (PVs) in residential networks, one major benefit is for rooftop PV units to counterbalance PEV loads, and hence normalize the useful life of distribution transformers. This effect has yet to be quantified in existing literature. This paper presents a study that evaluates the impact of PEV charging imposed on distribution transformer life, in the presence of rooftop PV units. The proposed methodology in this paper is applied to a real distribution system with various scenarios, including diversified PV and PEV penetration levels. Through deterministic and stochastic simulation, results reveal that distribution transformer increased loss-of-life (LOL), as a function of PEV charging, can be negated through the integration of distributed rooftop PV installation. © 2013 IEEE.

Online detection of partial discharge inside power transformer winding through IFRA

- Mohseni, Bahar, Hashemnia, Naser, Islam, Syed

  • Authors: Mohseni, Bahar , Hashemnia, Naser , Islam, Syed
  • Date: 2017
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2017 IEEE Power and Energy Society General Meeting, PESGM 2017; Chicago, United States; 16th-20th July 2017 Vol. 2018, p. 1-5
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  • Description: Predictive maintenance offers substantial benefits for detecting the early signs of power transformer faults before they burgeon into catastrophic failures. Online impulse frequency response analysis is a recently-developed diagnostic method for in service transformer with a promising outlook. This paper aims to propose an online partial discharge detection method the online IFRA test. To emulate the dynamic performance characteristics of in service transformer, 3D finite element model of the transformer is calculated in Maxwell Software. In post processing, the FEM sub-circuit model is exported into an external Maxwell Spice circuit to study the terminal behaviors of the transformer. A pulse signal simulating PD is injected between sections of the LV winding. The S transform is then applied to the recorded input and output signals in healthy and faulty conditions to construct the electrical impedance as well as the time-frequency contours of the transient responses. Also, a mechanical deformation is imposed on the transformer to compare its impact on online IFRA to the impact of internal partial discharge.

An experimental thermographic safety audit focusing on temperature rise vs load in electrical installations in a Bangladesh garments factory

- Islam, Syed, Huque, Mozammel, Khan, Liakot, Hossain, Imran

  • Authors: Islam, Syed , Huque, Mozammel , Khan, Liakot , Hossain, Imran
  • Date: 2017
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 4th International Conference on Advances in Electrical Engineering, ICAEE 2017; Dhaka, Bangladesh; 28th-30th September 2017 Vol. 2018, p. 561-564
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  • Description: Thermographic scanning of electrical installations is sometimes conducted as part of electrical safety audits. This scanning is mostly considered based on the present temperature identified on a particular device or location and according to a pre-specified temperature category. But in most of the cases the recommended temperature of the particular devices cannot be considered during temperature categorization. There are many electrical audits using Thermographic scanning and recommend solution based on normal category of temperature rather than manufacturer's suggestion or specified standard for particular electrical device. Now a days, thermographic scanning is being used in Readymade Garments (RMG) industries in Bangladesh in such simple way where details analysis are not in practice and hence exact recommendation is absent in reports. The importance of this topic is focused on the 4.2 million people working in more than 5,000 factories in Bangladesh, where 80% of the fire incident are caused by inappropriate electrical installation or short circuits (as per Fire Service and Civil Defense statistics of Bangladesh). Recently many violent industrial accidents caused death of more than 1,500 people in the last 3 years. Among these, majority of the incidents were due to unsafe electrical system and inappropriate maintenance. The paper will further explore the importance of thermal scanning on electrical devices and compare the temperature considering manufacturer's recommendation for identifying system errors. The paper is written based on previously published recommendations and based on conducting an experimental sample audit aimed to develop a thermography based auditing standard. Based on the statistical and systematic analysis of the obtained data (e.g. temperature values, visual abnormalities, comparative differences) the paper will further discuss the possible area(s) that can be improved by introducing the thermal reports for the safety audits. This paper is aimed to develop an auditing structure proposed to implement identified areas within a standard electrical safety audit process.

Application of SMES unit to improve the overall performance of DFIG-based WECS

- Khamaira, Mahmoud, Abu-Siada, Ahmed, Islam, Syed, Masoum, Mohammad

  • Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed , Masoum, Mohammad
  • Date: 2014
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2014 IEEE Power and Energy Society General Meeting; National Harbor, United States; 27th-31st July 2014 Vol. 2014, p. 1-5
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  • Description: Doubly Fed Induction Generators (DFIGs) are nowadays extensively used in variable speed wind power plants due to their advantages that include reduced converter rating, low cost, reduced losses with an improved efficiency, easy implementation of power factor correction schemes, variable speed operation and four quadrants active and reactive power control capabilities. On the other hand, DFIG sensitivity to grid disturbances, especially for the voltage dip represents the main disadvantage of the equipment. This paper presents the application of superconducting magnetic energy storage (SMES) unit to improve the overall performance of a DFIG-based wind energy conversion systems (WECS). Two control approaches namely; hysteresis current controller (HCC) along with proportional integral (PI) controller and a fuzzy logic (FL) controller for the SMES unit are presented and compared. Various grid codes are used to examine the capability of the two proposed controllers to improve the low voltage ride through (LVRT) capability of the DFIG to maintain the wind turbine connection to the grid through fault durations.
  • Description: IEEE Power and Energy Society General Meeting

Optimal scheduling with dynamic line ratings and intermittent wind power

- Banerjee, Binayak, Jayaweera, Dilan, Islam, Syed

  • Authors: Banerjee, Binayak , Jayaweera, Dilan , Islam, Syed
  • Date: 2014
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2014 IEEE Power and Energy Society General Meeting; National Harbor, United States; 27th-31st July 2014 Vol. 2014, p. 1-5
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  • Description: Limited transmission capacity may lead to wind curtailment during periods of high availability of wind. This paper presents an improved methodology to quantify the latent scheduling capacity of a power system taking into account stochastic variation in line-thermal rating, intermittency of wind, and mitigating the risk of network congestion associated with high penetration of wind. The approach is aimed at strategic planning of power systems in the context of power systems with short to medium length lines with a priori known unit commitment decisions and uses stochastic optimization with a two stage recourse action. Results suggest that a considerable level of wind penetration is possible with dynamic line ratings, without adversely affecting the risk of network congestion.
  • Description: IEEE Power and Energy Society General Meeting

A three-phase half-bridge cascaded inverter with reduced number of input DC supply

- Hasan, Mubashwar, Abu-Siada, Ahmed, Islam, Syed, Muyeen, S.

  • Authors: Hasan, Mubashwar , Abu-Siada, Ahmed , Islam, Syed , Muyeen, S.
  • Date: 2017
  • Type: Text , Conference proceedings
  • Relation: 2017 Australasian Universities Power Engineering Conference, AUPEC 2017; Melbourne, Australia; 19th-22nd November 2017 Vol. 2017, p. 1-7
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  • Description: Cascaded multilevel inverters (MLI) have recently received much attention due to its ability to perform well in various high voltage and high power applications with high efficiency. Cascaded inverters are able to generate high voltage output by utilizing a number of low voltage DC supplies and switches of low blocking voltage rating, which make cascaded MLI a cost effective choice for high voltage/power applications. The main drawback of cascaded MLI is the requirement of large number of isolated DC sources particularly, for three phase applications where the number of required input DC sources is three times that of single phase structure. In addition to the extra cost it will incur, the use of large number of DC supplies within the inverter will significantly increase its physical size, and complicate the management of such large number of DC sources. This paper presents a new topology for three phase MLI with a minimum number of input DC supplies. Symmetric and asymmetric input DC supply modes are developed for the proposed topology. Simulation and experimental results are provided to assess the performance of the proposed MLI topology.

Analysis of IEC 61850 for a Reliable Communication System between Substations

- Yang, Xin, Das, Narottam, Islam, Syed

  • Authors: Yang, Xin , Das, Narottam , Islam, Syed
  • Date: 2013
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2013 Australasian Universities Power Engineering Conference, AUPEC 2013; Hobart, Australia; 29th September-3rd October 2013 p. 1-6
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  • Description: IEC 61850 Standard was introduced to address the challenge presented by existence of the multiple protocols in substation communications, which include many proprietary protocols; and to address the challenge introduced by legacy complicated substation from both cost and complicity. In this paper, the simulation results of different types of IEC 61850 network system configurations using OPNET Modeler simulation software were presented and the influence on data rate and delay characteristics of these system configurations were evaluated. The simulated results confirm that the ring configured system suitable for higher loading characteristics and higher system reliability.

Security enhancement with nodal criticality based integration of PHEV micro grids

- Jayaweera, Dilan, Islam, Syed

  • Authors: Jayaweera, Dilan , Islam, Syed
  • Date: 2013
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2013 Australasian Universities Power Engineering Conference, AUPEC 2013; Hobart, Australia; 29th September-3rd October 2013 p. 1-6
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  • Description: Modern distribution networks are increasingly vulnerable to disturbances and improving the security of supply to customers are complex and challenging with the traditional approach. This paper presents a new approach to enhance the security of power supply in an active distribution network by integrating PHEV (Plug-in Hybrid Electric Vehicle) based micro grids on the basis of the nodal criticality. The nodal criticality is assessed by integrating operational uncertainties of events into samples of Monte Carlo simulation and classifying load interruptions on the basis of their magnitudes and frequencies. Criticality of the system stress that results nodal loads shedding is classified into arrays of clusters based on the magnitudes of interrupted loads at samples. The critical clusters that represent largest disturbances to the respective nodal loads are served with PHEV micro grids. Case studies are performed, and the results suggest that the security of distribution networks can be significantly improved with the proposed approach.

Battery impedance measurement using sinusoidal ripple current emulator

- Hossain, Kamal, Islam, Syed, Park, Sung-Yeul

  • Authors: Hossain, Kamal , Islam, Syed , Park, Sung-Yeul
  • Date: 2017
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 9th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2017; Cincinnati, United States; 1st-5th October 2017 Vol. 2017, p. 2754-2759
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  • Description: This paper presents a sinusoidal ripple current (SRC) emulator which superimposes an ac ripple current frequency into a dc charging current in order to produce a sinusoidal ripple current without a ripple current controller. It can be used for several purposes:1) to analyze the impact of ac ripple current magnitude and frequency on the battery internal characteristics; 2) to determine the parameters related to thermal rise and lithium plating; 3) to obtain more updated parameter information for improved utilization of a battery; 4) to determine the optimal ripple current frequency at the minimum impedance point by sweeping the ripple current frequency; 5) to utilize the obtained impedance data for estimating the battery circuit parameters and SOC level. The internal characteristics of batteries are complex and dynamic; therefore, it is beneficial to use the SRC emulator to validate SRC performance in a battery stack before integrating a SRC algorithm into a battery charger. This paper describes the development procedure of a SRC emulator to produce the electrochemical impedance spectroscopy (EIS) measurement for measuring the battery internal impedance. In order to validate the performance of the SRC emulator, a 12.8 V, 40 Ah Li-ion battery was charged at C/8 rate in CC mode with ± 1 App ac ripple current perturbation with an impedance from 20 Hz to 2 kHz.

Impact of buckling deformation on the FRA signature of power transformer

- Amini, Arman, Das, Narottam, Islam, Syed

  • Authors: Amini, Arman , Das, Narottam , Islam, Syed
  • Date: 2013
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2013 Australasian Universities Power Engineering Conference, AUPEC 2013; Hobart, Australia; 29th September-3rd October 2013 p. 1-4
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  • Description: Power transformer is an important asset within the electrical power system network. Frequency Response Analysis (FRA) has been developing in popularity in recent years as a tool to detect mechanical deformation of power transformers winding. Since the FRA has been relying on graphical analysis, it calls for an expert person to analyze the results to detect the type of the fault and its location. There are no reliable guidelines for FRA signature in the event that a failure occurs in service and the impact can be far reaching. The concept of FRA has been successfully used as a diagnostic technique to detect the winding deformation, core and clamping structure for the power transformers. This paper investigated the impact of the forced and free winding buckling based on the variation of the electrical parameters to show how these faults vary the FRA signature.

Alleviating post-contingency congestion risk of wind integrated systems with dynamic line ratings

- Banerjee, Binayak, Jayaweera, Dilan, Islam, Syed

  • Authors: Banerjee, Binayak , Jayaweera, Dilan , Islam, Syed
  • Date: 2014
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-6
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  • Description: One of the factors hindering the large scale integration of wind power is the post contingency congestion of a network due to limited availability of network capacity and auxiliary constraints. Under such conditions, the network operators can potentially request a curtailment of wind farm output if the remedial strategies fail. The paper investigates this problem in detail and proposes a mathematical framework to capture the post contingency spare capacity of network assets that is required to limit the wind curtailment. The proposed approach incorporates stochastic variation in asset thermal rating; models network congestion, and quantifies the risk of congestion using an extended version of conic-quadratic programming based optimization. The uniqueness of the proposed mathematical model is that it converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation penalty. The results suggest that the wind utilization can be maximized if the networks are operated 30-50% less than the nominal rating of the assets.

Hydrologic impact of climate change on Murray–Hotham catchment of Western Australia : A projection of rainfall–runoff for future water resources planning

- Islam, Syed, Bari, Mohammed, Anwar, Faisal

  • Authors: Islam, Syed , Bari, Mohammed , Anwar, Faisal
  • Date: 2014
  • Type: Text , Journal article
  • Relation: Hydrology and Earth System Sciences Vol. 18, no. 9 (2014), p. 3591-3614
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  • Description: Reduction of rainfall and runoff in recent years across southwest Western Australia (SWWA) has attracted attention to the climate change impact on water resources and water availability in this region. In this paper, the hydrologic impact of climate change on the Murray–Hotham catchment in SWWA has been investigated using a multi-model ensemble approach through projection of rainfall and runoff for the periods mid (2046–2065) and late (2081–2100) this century. The Land Use Change Incorporated Catchment (LUCICAT) model was used for hydrologic modelling. Model calibration was performed using (5 km) grid rainfall data from the Australian Water Availability Project (AWAP). Downscaled and bias-corrected rainfall data from 11 general circulation models (GCMs) for Intergovernmental Panel on Climate Change (IPCC) emission scenarios A2 and B1 was used in LUCICAT model to derive rainfall and runoff scenarios for 2046–2065 (mid this century) and 2081–2100 (late this century). The results of the climate scenarios were compared with observed past (1961–1980) climate. The mean annual rainfall averaged over the catchment during recent time (1981–2000) was reduced by 2.3%with respect to the observed past (1961–1980) and the resulting runoff reduction was found to be 14 %. Compared to the past, the mean annual rainfall reductions, averaged over 11 ensembles and over the period for the catchment for A2 scenario are 13.6 and 23.6% for mid and late this century respectively while the corresponding runoff reductions are 36 and 74%. For B1 scenario, the rainfall reductions were 11.9 and 11.6% for mid and late this century and the corresponding runoff reductions were 31 and 38%. Spatial distribution of rainfall and runoff changes showed that the rate of changes were higher in high rainfall areas compared to low rainfall areas.Temporal distribution of rainfall and runoff indicate that high rainfall events in the catchment reduced significantly and further reductions are projected, resulting in significant runoff reductions. A catchment scenario map has been developed by plotting decadal runoff reduction against corresponding rainfall reduction at four gauging stations for the observed and projected periods. This could be useful for planning future water resources in the catchment. Projection of rainfall and runoff made based on the GCMs varied significantly for the time periods and emission scenarios. Hence, the considerable uncertainty involved in this study though ensemble mean was used to explain the findings.

Assessment of post-contingency congestion risk of wind power with asset dynamic ratings

- Banerjee, Binayak, Jayaweera, Dilan, Islam, Syed

  • Authors: Banerjee, Binayak , Jayaweera, Dilan , Islam, Syed
  • Date: 2015
  • Type: Text , Journal article
  • Relation: International Journal of Electrical Power and Energy Systems Vol. 69, no. (2015), p. 295-303
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  • Description: Large scale integration of wind power can be deterred by congestion following an outage that results in constrained network capacity. Post outage congestion can be mitigated by the application of event control strategies; however they may not always benefit large wind farms. This paper investigates this problem in detail and proposes an advanced mathematical framework to model network congestion as functions of stochastic limits of network assets to capture post contingency risk of network congestion resulting through the constrained network capacity that limits high penetration of wind. The benefit of this approach is that it can limit the generation to be curtailed or re-dispatched by dynamically enhancing the network latent capacity in the event of outages or as per the need. The uniqueness of the proposed mathematical model is that it converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation penalty. The case study results with large and small network models suggest that the following an outage, wind utilization under dynamic line rating can be increased considerably if the wind power producers maintain around a 15% margin of operation.

Reactive power distribution strategy using power factor correction converters for smart home application

- Islam, Syed, Maxwell, Shawn, Hossain, Kamal, Park, Sung-Yeul, Park, Sungmin

  • Authors: Islam, Syed , Maxwell, Shawn , Hossain, Kamal , Park, Sung-Yeul , Park, Sungmin
  • Date: 2016
  • Type: Text , Conference proceedings , Conference paper
  • Relation: 2016 IEEE Energy Conversion Congress and Exposition, ECCE 2016; Milwaukee, United States; 18th-22nd September 2016 p. 1-6
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  • Description: Multiple unit of PFC converters can be utilized for better power quality in the residential applications. It is important to set proper amount of reactive power contribution from each unit of PFC converter to reduce power loss and increase stability. To set the referenced amount of reactive power contribution for each PFC converter, a dynamic supervisory controller is necessary. In this paper, a wireless based supervisory controller is introduced to mitigate the problem. Multiple unit of unidirectional bridgeless ac-dc boost PFC converters were used as reactive power resources in a smart home application. The supervisory controller is comprised of a discrete Proportional-Integral controller and distributor which sets the reactive power references for each PFC converter. The controller was designed based on the systems identification method. The controller was designed and simulated considering different communication delays. In the ideal condition, the system had no communication delay. However, actual practical system had some reasonable delay. The effect of the use of supervisory controller was observed for dynamic load changing conditions. The simulation was done by using SIMULINK. Reactive power consumption from grid becomes 0VAR within 0.25 second for ideal condition. However, for the actual condition this become 9.35 seconds.

Modeling of multi-junction photovoltaic cell using MATLAB/Simulink to improve the conversion efficiency

- Das, Narottam, Wongsodihardjo, Hendy, Islam, Syed

  • Authors: Das, Narottam , Wongsodihardjo, Hendy , Islam, Syed
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Renewable Energy Vol. 74, no. (2015), p. 917-924
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  • Description: This paper focuses on modeling of multi-junction solar cell (MJSC) to improve the conversion efficiency using MATLAB/Simulink software. The multi-junction photovoltaic (PV) cell is investigated to obtain its maximum performance compare to the conventional silicon PV cell. MATLAB/Simulink modeled results show that tandem cell can provide almost 3-times maximum power compared to the conventional PV cells. Maximum power point tracker (MPPT) has also been performed to improve the conversion efficiency of the PV systems. The MPPT is able to assist the PV cells to attain more power efficiently and deliver electricity to the grid.