Domestic load management with coordinated photovoltaics, battery storage and electric vehicle operation
- Authors: Das, Narottam , Haque, Akramul , Zaman, Hasneen , Morsalin, Sayidul , Islam, Syed
- Date: 2023
- Type: Text , Journal article
- Relation: IEEE Access Vol. 11, no. (2023), p. 12075-12087
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- Description: Coordinated power demand management at residential or domestic levels allows energy participants to efficiently manage load profiles, increase energy efficiency and reduce operational cost. In this paper, a hierarchical coordination framework to optimally manage domestic load using photovoltaic (PV) units, battery-energy-storage-systems (BESs) and electric vehicles (EVs) is presented. The bidirectional power flow of EV with vehicle to grid (V2G) operation manages real-time domestic load profile and takes appropriate coordinated action using its controller when necessary. The proposed system has been applied to a real power distribution network and tested with real load patterns and load dynamics. This also includes various test scenarios and prosumer's preferences e.g., with or without EVs, number of EV owners, number of households, and prosumer's daily activities. This is a combined hybrid system for hierarchical coordination that consists of PV units, BES systems and EVs. The system performance was analyzed with different commercial EV types with charging/ discharging constraints and the result shows that the domestic load demand on the distribution grid during the peak period has been reduced significantly. In the end, this proposed system's performance was compared with the prediction-based test techniques and the financial benefits were estimated. © 2013 IEEE.
Reverse blocking over current busbar protection scheme based on IEC 61850 architecture
- Authors: Kumar, Shantanu , Abu-Siada, Ahmed , Das, Narottam , Islam, Syed
- Date: 2023
- Type: Text , Journal article
- Relation: IEEE Transactions on Industry Applications Vol. 59, no. 2 (2023), p. 2225-2233
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- Description: Substation Automation System (SAS) is currently in a matured state of technology that shall facilitate transformational changes from conventional protection scheme. IEC 61850 protocol is considered as the crux of digital SAS due to its multifunction features that include seamless communication, ability to integrate various intelligent electronic devices, potential for improved real-time condition monitoring, reliable protection, and control of critical electrical assets. Because the application of IEC 61850 in SAS is relatively new and has not fully implemented in many substations yet, further feasibility studies using multivendor equipment to assess its performance under different operating conditions is imperative. In this article, a practical reliable and efficient reverse blocking over current bus bar protection scheme based on IEC 61850 is implemented and tested. Also, a comparison of digital SAS and conventional protection scheme is presented to highlight the superiority of the former one. Experimental results attest the reliability and effectiveness of the proposed digital protection scheme along with the accuracy and security of transmitting data packets using sampled values and generic objective-oriented substation event communication protocols adopted by IEC 61850. © 2022 IEEE.
Review of the legacy and future of IEC 61850 protocols encompassing substation automation system
- Authors: Kumar, Shantanu , Abu-Siada, Ahmed , Das, Narottam , Islam, Syed
- Date: 2023
- Type: Text , Journal article , Review
- Relation: Electronics (Switzerland) Vol. 12, no. 15 (2023), p.
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- Description: Communication protocols play a pivotal role in the substation automation system as they carry critical information related to asset control, automation, protection, and monitoring. Substation legacy protocols run the assets’ bulk data on multiple wires over long distances. These data packets pass through multiple nodes, which makes the identification of the location and type of various malfunctions a challenging and time-consuming task. As downtime of substations is of high importance from a regulatory and compliance point of view, utilities are motivated to revisit the overall scheme and redesign a new system that features flexibility, adaptability, interoperability, and high accuracy. This paper presents a comprehensive review of various legacy protocols and highlights the path forward for a new protocol laid down as per the IEC 61850 standard. The IEC 61850 protocol is expected to be user-friendly, employ fiber optics instead of conventional copper wires, facilitate the application of non-conventional instrument transformers, and connect Ethernet wires to multiple intelligent electronic devices. However, deployment of smart protocols in future substations is not a straightforward process as it requires careful planning, shutdown and foreseeable issues related to interface with proprietary vendor equipment. Along with the technical issues of communication, future smart protocols call for advanced personnel and engineering skills to embrace the new technology. © 2023 by the authors.
Comparison between wired versus wireless mode of digital protection scheme leveraging on PRP topology
- Authors: Kumar, Shantanu , Abu-Siada, Ahmed , Das, Narottam , Islam, Syed
- Date: 2022
- Type: Text , Conference paper
- Relation: 4th IEEE Sustainable Power and Energy Conference, iSPEC 2022, Virtual, online, 4-7 December 2022, Proceedings - 2022 IEEE Sustainable Power and Energy Conference, iSPEC 2022
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- Description: Applications of Digital communication in power systems have undergone revolutionary changes in the last decade due to the advancement in technology encompassing substation automation system (SAS). The reasons for veering away from traditional copper based secondary wiring for protection schemes to Ethernet and fiber optic (FO) include economic gains, faster project delivery, ease of diagnostics, less engineering and design efforts. However, digital systems still comprise some challenges such as latencies, data losses, and packet clogging during high traffic. Errors in packets transmission and associated difficulties in publication and subscription of generic object-oriented substation events (GOOSE) and sampled value (SV) packets in a Wide Area Network (WAN) substation based on IEC 62439-3 protocol call for a detailed investigation. This paper compares the performance of wired and wireless mode of digital secondary scheme based on simulation and physical set up leveraging on Parallel Redundancy Protocol (PRP) topology. It presents different scenarios for SV packets in a process bus and provides analysis to the data packet transmission due to traffic and network clogging in wired and wireless topologies. © 2022 IEEE.
Design of hybrid power system stabilizer for dynamic stability improvement using cultural algorithm
- Authors: Patel, Jasmeen , Das, Narottam , Islam, Syed
- Date: 2022
- Type: Text , Conference paper
- Relation: 4th IEEE Sustainable Power and Energy Conference, iSPEC 2022, Virtual, online, 4-7 December 2022, Proceedings - 2022 IEEE Sustainable Power and Energy Conference, iSPEC 2022
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- Description: In power system the stability is an important property that varies on the operational condition and the interruption to which it is exposed. The power system network endangered to the similar disruption can be stable at one operational situation (e.g., in off-peak hours) and not stable at another (e.g., at peak times). Similarly, a network at one operational situation can be stable to one disturbance and not stable to another. Consequently, stability reports generally involve the analysis of several cases, in order to cover various disruptions of interest and the key points of operation of the system. This research recommends various stabilizers such as, Power system stabilizers (PSS), Proportional Integration Differentiation (PID) and Fractional Order PID (FOPID) to decrease oscillations due to small signal disruption. The PSS-Voltage stabilizer generates impulses at the time of speed-change which usually results in positive PSS output. Using the FOPID procedure in relation with PSS, this approach can decrease these impulses. Using this approach, the generated impulses are finally decreased. Genetic Algorithm, particle swarm optimization and cultural algorithm are used for parameter fine-tuning of all the stabilizers. All these algorithms will help to tune parameters at soft computing level and then again tuned by two stabilizers which are FOPID and PSS. Now, again two stabilizers will tune and provide output needs to compare and average output to get required tuned values. Finally, the average of two stabilizers will field circuit and drive rotor according to the value given to it. © 2022 IEEE.
Power quality improvement of a solar powered bidirectional smart grid and electric vehicle integration system
- Authors: Paidimukkala, Nikitha , Das, Narottam , Islam, Syed
- Date: 2022
- Type: Text , Conference paper
- Relation: 4th IEEE Sustainable Power and Energy Conference, iSPEC 2022, Virtual, online, 4-7 December 2022, Proceedings - 2022 IEEE Sustainable Power and Energy Conference, iSPEC 2022
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- Description: This research paper mainly focuses on photovoltaic (PV) smart grid (SG) and electric vehicles (EVs) integration with two-way power flow capabilities by charging/discharging and power quality improvements using the power converters. Due to the increase of energy demand by rapid growth of population, it is necessary to modernize the power grid with improved power quality, such that the energy converted by solar PV (SPV) can be transmitted and stored as the excess amount of power in terms of batteries to use at peak load demand. The batteries of the EVs charge at a low level of demand and discharged at peak demand. The EVs can function both as a load and an energy supplier to the SG. The simulation results demonstrate the functioning of interfaced smart G2V system by observing and improving the factors such as power factor, power regulation and elimination of harmonics by constructing a power electronic network which can perform bidirectional power flow and balancing the network using MATLAB/Simulink software. Subsequentially, the improvement of power quality of the integrated system by analyzing power compensation, voltage regulation and harmonics mitigation of the integration system has been examined in detail. © 2022 IEEE.
A Fast and Reliable Blocked Bus Bar Protection Scheme Leveraging on Sampled Value and GOOSE Protection based on IEC 61850 Architecture
- Authors: Kumar, Shantanu , Abu-Siada, Ahmed , Das, Narottam , Islam, Syed
- Date: 2021
- Type: Text , Conference paper
- Relation: 31st Australasian Universities Power Engineering Conference, AUPEC 2021, Virtual, Online 26 to 30 September 2021, Proceedings of 2021 31st Australasian Universities Power Engineering Conference, AUPEC 2021
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- Description: Substation Automation System (SAS) is in a matured state and promises to replace conventional protection scheme. It has created a new paradigm in its application for future smart grids. The multifunction features of IEC 61850 facilitate this technology to reliably monitor, protect and control critical assets. Mostly agree, the intelligent electronic devices (IEDs) and substation automation features have the same effect as 'html' had in developing web technology on IT system in 1990's. However, in order to be acceptable completely, this technology needs to gain confidence of end user, it needs to be researched further using multivendor equipment and experimented in a network comprising of complex secondary protection schemes. In this paper, a practical Blocked Busbar Protection (BBP) scheme have been implemented and tested for a single bus bar scheme, leveraging on Sampled Values (SV) and Generic Object Oriented Substation Event (GOOSE) at laboratory to prove its reliability and improvement in technology. This experiment has been carried out for three scenarios in a simulated substation network related to a process plant industry. Furthermore, this laboratory-based experiment with multivendor IEDs evaluated performance of an Ethernet and FO based process bus network to validate overall performance of BBP protection scheme. It concluded with a comparison between digital and conventional protection scheme with recommendation for future applications. © 2021 IEEE.
MATLAB/Simulink Modelling of Multi-junction PV Cell for Conversion Efficiency Improvement using Maximum Power Point Tracking Method
- Authors: Dave, Malvika , Das, Narottam , Islam, Syed
- Date: 2021
- Type: Text , Conference paper
- Relation: 2021 IEEE PES Innovative Smart Grid Technologies - Asia, ISGT Asia 2021, Brisbane, 5-8 December 2021
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- Description: This research focuses the modelling of multi-junction solar cells (MJSCs) for conversion efficiency improvement considering maximum power point tracking (MPPT) utilizing MATLAB/Simulink software. The conversion efficiency of a single-junction photovoltaic (PV) cell is comparatively low than the MJSCs (GaInP/GaInAs/Ge). The cell conversion efficiency is improved by forming MJSCs, where two or more single junctions are stacked, and higher conversion efficiency is achieved using the MPPT method in MATLAB/Simulink environment to maximize the output power of PV panel. This research considered different parameters of MJSCs, such as lattice matching, bandgap matching, current matching to improve the conversion efficiency. The maximum performance of MJSCs also obtained through the I-V and P-V characteristics by varying different environmental factors, such as temperature and irradiance in MATLAB/Simulink environment. perturb and observe (P&O) MPPT algorithm which is the most suitable for PV applications. Finally, two different Pulse Width Modulation techniques are compared and analyzed with respect to Perturb and observe by applying Quasi Z source inverter (QZSI) within the MATLAB/Simulink environment to enhance the conversion efficiency of triple MJSC. © 2021 IEEE
Mitigation of Power Quality Issues with Solar PV Penetration into LV/MV Distribution System
- Authors: Patel, Bhoomi , Das, Narottam , Islam, Syed
- Date: 2021
- Type: Text , Conference paper
- Relation: 2021 IEEE PES Innovative Smart Grid Technologies - Asia, ISGT Asia 2021, Brisbane, 5-8 December 2021
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- Description: Over the last decades, solar photovoltaic (PV) system on the low and medium voltage distribution network is growing dramatically. The power grids are still facing the experience of more penetration to satisfy electricity demand of the consumer. Another reason for solar PV penetration is government subsidies for the customers, decreasing the capital cost of solar PV, feed-in-tariff and to balance the CO2 emission from the atmosphere. The integration of PV system in low voltage or medium voltage ((LV/MV) distribution networks is raising new challenges in terms of power quality (PQ). In the LV/MV distribution networks, PQ problems are voltage sag and swell are the most serious concern, and it occurs when residential renewable energy sources (i.e., solar PV) produce more energy than the local demand. As per the PQ studies, voltage sag/swell issues in the LV/MV power grid considered to be the most common type of PQ issue. Impact of this type of issue on sensitive loads is harsh. Hence, different types of solution have been used to protect sensitive loads from such voltage problems, but the dynamic voltage restorer is to be considered, effective and efficient solution. Dynamic Voltage Restorer (DVR) is a series connected power electronic device which is used to alleviate the voltage sag/swell problem in the distribution system and restore the load voltage to the required value. Therefore, the main objective of this research project is to investigate and understand the impact of PQ issues in LV/MV distribution system and aim is to alleviate them. MATLAB/Simulink software is used to solve the PQ issues by designing battery supported DVR with energy storage systems. The performance of battery supported DVR is designed, simulated in MATLAB/Simulink software environment, and analysed in detail. © 2021 IEEE
Toward a substation automation system based on IEC 61850
- Authors: Kumar, Shantanu , Abu-Siada, Ahmed , Das, Narottam , Islam, Syed
- Date: 2021
- Type: Text , Journal article
- Relation: Electronics (Switzerland) Vol. 10, no. 3 (2021), p. 1-16
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- Description: With the global trend to digitalize substation automation systems, International Electro technical Commission 61850, a communication protocol defined by the International Electrotechnical Commission, has been given much attention to ensure consistent communication and integration of substation high-voltage primary plant assets such as instrument transformers, circuit breakers and power transformers with various intelligent electronic devices into a hierarchical level. Along with this transition, equipment of primary plants in the switchyard, such as non-conventional instrument transformers, and a secondary system including merging units are expected to play critical roles due to their fast-transient response over a wide bandwidth. While a non-conventional instrument transformer has advantages when compared with the conventional one, extensive and detailed performance investigation and feasibility studies are still required for its full implementation at a large scale within utilities, industries, smart grids and digital substations. This paper is taking one step forward with respect to this aim by employing an optimized network engineering tool to evaluate the performance of an Ethernet-based network and to validate the overall process bus design requirement of a high-voltage non-conventional instrument transformer. Furthermore, the impact of communication delay on the substation automation system during peak traffic is investigated through a detailed simulation analysis. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Mitigation of sympathetic tripping leveraging on IEC 61850 Protocol
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed
- Date: 2019
- Type: Text , Conference proceedings
- Relation: 2018 Australasian Universities Power Engineering Conference (AUPEC); Auckland, New Zealand; 27-30 Nov. 2018 p. 1-6
- Full Text: false
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- Description: Intelligent Electronic Devices (IEDs) diagnose faults and traffic issues of data packets in a reliable and efficient manner in a substation environment. These devices determine abnormal system condition, wide area disturbances offering greater flexibility to the operator in terms of condition monitoring and diagnostics. In a distribution system, end user get multiple faults in the network and one such nuisance disruption of power on a faulty feeder results in sympathetic tripping. Sympathetic tripping occurs during high load conditions causing entire protection system to spuriously trip due to an out of section fault. Occurrence of such faults could be attributed to load unbalance in the distribution feeders, delayed voltage recovery conditions, voltage swell/sag in the feeders etc. Usually, this phenomenon occur when loads containing low inertia rotating equipment are connected to distribution feeders. In this paper, an Optimized Network Engineering Tool (OPNET) is used to simulate, mitigate faults attributed to Sympathetic Tripping in a laboratory environment.
Nano-structured GaAs solar cell design, simulation and analysis for conversion efficiency improvement
- Authors: Tan,Shiyao , Das, Narottam , Helwig, A , Islam, Syed
- Date: 2019
- Type: Text , Conference proceedings
- Relation: 2018 Australasian Universities Power Engineering Conference (AUPEC); Auckland, New Zealand; 27-30 Nov. 2018 p. 1-6
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- Description: This paper discusses nano-structured GaAs solar cell design and analysis for conversion efficiency improvement by increasing the light transmission and absorption, reducing the light reflection. The focus of this research is to construct different type of nano-grating shaped GaAs solar cells with various nano-grating heights and pitches, to compare the simulation results and find a suitable nano-structure that can provide higher conversion efficiency. Finite difference time domain (FDTD) simulation tool is used to simulate and calculate the light reflection, transmission and absorption for different nano-grating shapes, such as, parabolic, triangular, trapezoidal and rectangular. Based on the simulation results, it has been confirmed that the light reflection of parabolic shaped nano-grating structures is higher than triangular nano-grating structures, but it is lower than rectangular and trapezoidal shaped nano-grating structures. Moreover, the simulation results confirmed that the light transmission of parabolic shaped nano-grating structures is about 62.3% having a 200-nm grating height and an 810-nm grating pitch, which is about 22% higher than the rectangular (i.e., flat) type substrates.
Nano-structured photovoltaic cell design for high conversion efficiency by optimizing various parameters
- 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.
Verification of latency and delays related to a digital topology based on IEC 61850
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed , Abu-Siada, Ahmed
- Date: 2019
- Type: Text , Conference proceedings , Conference paper
- Relation: 2019 29th Australasian Universities Power Engineering Conference (AUPEC2019); Momi Bay, Fiji; 26th-29th November 2019
- Full Text: false
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- Description: Digital Communication systems have matured to a point of acceptance in the last decade enormously based on IEC 61850 guidelines from Substation Automation System (SAS) perspective. However, these networks have issues related to latency, data clogging delays, errors etc. in the digital protection system. Measuring propagation delays and assessing the performance of IED's and other peripherals in an Ethernet topology play a critical role in relay coordination setting. This paper discusses issues associated with a digital network and addresses the problems that could mitigate spurious tripping or compromise the protection of the assets in the feeders leading to a reliable operation of the protection system. The discussion in this paper is carried out based on a case study related to a digital star topology using Optimized Network Engineering Tool (OPNET) software of a 132/22-kV zone substation. We report the practical case of measuring delay time during frame exchanges of Generic Object Oriented Substation Event (GOOSE) and Sampled Value (SV) messages amongst the IED' and peripherals.
High voltage substation automation and protection system based on IEC 61850
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed
- Date: 2018
- Type: Text , Conference proceedings
- Relation: 2018 Australasian Universities Power Engineering Conference (AUPEC);Auckland, New Zealand; 27-30 Nov. 2018
- Full Text: false
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- Description: Digital Communication is the future of High Voltage (HV) substation automation, protection and control. It not only offer ease of diagnostics but acts fast to isolate healthy feeders from faulty ones. The effect of this digital protection technology is being appreciated by many utilities and industries for the benefit it offers to them and looks to be the future. Some of the utilities are replacing their secondary copper wires with Fibre Optics (FO) and Ethernet wires as they want load the cable trays less and identify the FO better than the secondary copper wires. Conventional relays are being replaced with Intelligent Electronic Devices (IEDs) during asset management replacement program. Switchyard equipment such as instrument transformers filled with oil and SF6 gas are being replaced with Non-Conventional Instrument Transformer (NCITs). Ushering new devices into the network are not without challenges. These devices and peripherals cannot be put into use by the end user without proper assessment and needs to be validated with number of tests for its performances. To get end users acceptance, laboratory and field tests are carried out to study the propagation delays and performance issues as applicable to digital automation and protection scheme. This paper discusses an early detection of the loss of data packets in a star connected Ethernet Substation Automation Systems (SAS). Understanding a real model in a lab environment is an important step towards performance evaluation and identification of issues. With the involvement of multiple manufacturer in the digital substation, it is good to set a trial of the interoperability of equipment involving their products which could address critical protection issues. This paper focuses on a star connected architecture using an Optimized Network Engineering Tool (OPNET) lab-based software simulating the latency and delays of a digital protection scheme in a 132/22-kV zone substation.
Implementing PRP and HSR Schemes in a HV Substation based on IEC62439-3
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed
- Date: 2018
- Type: Text , Conference proceedings
- Relation: 2018 Condition Monitoring and Diagnosis (CMD); Perth, WA, Australia; 23-26 Sept. 2018 p. 1-5
- Full Text: false
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- Description: High speed communication is an essential feature of Substation Automation and Control. Existing International Electro-technical Commission (IEC) 61850 guidelines substation automation and communication systems have few shortcomings in the protection architecture which necessitated an upgrade to another guideline. This has been addressed better in IEC 62439-3 standard encompassing Parallel Redundancy Protocol (PRP) and High-availability Seamless Redundancy (HSR), Earlier there have been number of issues with IEC 61850, due to single port failure, data losses and interoperability related to multi-vendor equipment. The enhanced features of a Double Attached Node component based on IEC 62439-3, provide redundancy in protection by virtue of having two active frames circulating in the ring. These frames send out copies in the ring. Should one of them be lost, the destination node will receive alternate frame, ensuring flawless data transfer at a significant faster speed in a multi-vendor equipment ensuring the circuit is fault resilient. PRP and HSR topologies promise enhanced reliability over IEC 61850 standard due to faster processing capabilities, increased availability in the scheme with least delay time in circulating data packet in wireless communication in the network. This paper exhibit performance of PRP and HSR topologies addressing redundancy within the network ring leveraging on IEC 62439-3.
Performance evaluation of two interconnected high voltage utility substations using PRP topology based on IEC 62439-3
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed
- Date: 2018
- Type: Text , Conference proceedings
- Relation: 2017 Australasian Universities Power Engineering Conference, AUPEC 2017; Melbourne, Australia; 19th-22nd November 2017 Vol. 2017, p. 1-5
- Full Text: false
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- Description: In a modern power system network having multiple interconnected High Voltage (HV) substations, communication amongst Intelligent Electronic Devices (IED) becomes an important feature in an automation system. Time critical information, such as feeder faults, overcurrent, under frequency messages between multiple geographically isolated substations have opened up number of issues related to reliability in protection, automation and control. There are problems related to latency, data loss and transfer of Sampled Value (SV) packets transmitted to these inter-connected substations on radio wireless and Ethernet mode linked up in a Wide Area Network (WAN) configuration. Few other key area of concerns in a digital protection scheme are packet losses, errors in packet arrival at destination, latency in transmission, End to End delay in packet transfer due to flooding of the network, out of sequence packet arrival etc. Error prone packets could seriously compromise the protection scheme and endanger the safety of primary plant assets in a transmission substation. This paper investigates performance of SV packet transmission between two interconnected substations]. Practical simulations were performed to evaluate the performance of SV packets in a laboratory set up to assess the performance of digital protection scheme based on Parallel Redundancy Protocol (PRP) topology involving digital equipment such as Merger Units (MUs), switches, IEDs and Redundant boxes (Red box), etc.
A preliminary study on conversion efficiency improvement of a multi-junction PV cell with MPPT
- Authors: Das, Narottam , Wongsodihardjo, Hendy , Islam, Syed
- Date: 2016
- Type: Text , Book chapter
- Relation: Smart Power Systems and Renewable Energy System Integration (part of the Studies in Systems, Decision and Control book series) Chapter 4 p. 49-73
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- Description: This chapter presents a preliminary study conducted to improve photovoltaic (PV) cell conversion efficiency using MATLAB/Simulink platform. The study uses multi-junction solar cell and investigates the maximum performance compared with a conventional silicon PV cell. Maximum Power Point Tracker (MPPT) is applied to assess the conversion efficiency of the PV system. Study integrates thermoelectric generator (TEG) with PV modules because the PV cells work by converting high frequency irradiation where as a TEG has the ability to convert wasted low frequency heat to the electricity. The combination delivers more power and contributes to enhance the conversion efficiency of a PV system. The simulation results show that a tandem cell can provide a considerable higher power with a conventional PV cell operation.
Design and analysis of nano-structured gratings for conversion efficiency improvement in GaAs solar cells
- Authors: Das, Narottam , Islam, Syed
- Date: 2016
- Type: Text , Journal article
- Relation: Energies Vol. 9, no. 9 (2016), p. 1-13
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- Description: This paper presents the design and analysis of nano-structured gratings to improve the conversion efficiency in GaAs solar cells by reducing the light reflection losses. A finite-difference time domain (FDTD) simulation tool is used to design and simulate the light reflection losses of the subwavelength grating (SWG) structure in GaAs solar cells. The SWG structures perform as an excellent alternative antireflective (AR) coating due to their capacity to reduce the reflection losses in GaAs solar cells. It allows the gradual change in the refractive index that confirms an excellent AR and the light trapping properties, when compared with the planar thin film structures. The nano-rod structure performs as a single layer AR coating, whereas the triangular (i.e., conical or perfect cone) and parabolic (i.e., trapezoidal/truncated cone) shaped nano-grating structures perform as a multilayer AR coating. The simulation results confirm that the reflection loss of triangular-shaped nano-grating structures having a 300-nm grating height and a 830-nm period is about 2%, which is about 28% less than the flat type substrates. It also found that the intermediate (i.e., trapezoidal and parabolic)-shaped structures, the light reflection loss is lower than the rectangular shaped nano-grating structure, but higher than the triangular shaped nano-grating structure. This analysis confirmed that the triangular shaped nano-gratings are an excellent alternative AR coating for conversion efficiency improvement in GaAs solar cells.
Performance evaluation of a process bus architecture in a zone substation based on IEC 61850-9-2
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed
- Date: 2016
- Type: Text , Conference proceedings , Conference paper
- Relation: IEEE PES Asia-Pacific Power and Energy Engineering Conference, APPEEC 2015; Brisbane, Australia; 15th-18th November 2015 Vol. 2016, p. 1-5
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- Description: Ethernet communication has been the back bone of high speed communication in digital substations from protection relaying, control and automation perspective. Major substation manufacturers have been constantly upgrading softwares and adding new features in their Intelligent Electronic Devices (IED's) to carry out multiple functions in process bus devices. This paper presents simulation results with respect to the delay in packets transfer in an Ethernet environment. Understanding the delay in packet transfer of Generic Object Oriented Substation Event (GOOSE) and Sampled Values (SV) shall assist the user in understanding the substation automation, control and protection of substation primary plants such as current transformers (CT's), voltage transformers (VT's), circuit breakers etc. connected in the network during a fault condition Conventional substation uses Merging Units (MU's) to communicate with the IED's featuring IEC 61850-9-2 standard. This standard exhibits transparency and standardization of data communication while addressing issues related to reliability, packet sharing, and maintainability, etc. However, process bus architecture is yet to be widely accepted in the industry and needs further validation due to lack of confidence. This paper evaluates the performance of a digital protection scheme in a zone substation operating at 132kV, featuring IEC 61850-9-2 IED's and using an optimized network engineering tool (OPNET) simulator. Understanding the delay in receiving time critical GOOSE and sampled value SV messages from protection perspective is critical as loss of data could cause malfunction in the protection jeopardizing vital substation plants.