Ashish Shrestha | Kathmandu University (original) (raw)
Teaching Documents by Ashish Shrestha
A Particle Swarm Optimization (PSO) method is proposed for the optimal allocation of Distributed ... more A Particle Swarm Optimization (PSO) method is proposed for the optimal allocation of Distributed Generation (DG) in the radial distribution system (RDS) for voltage profile improvement. The proposed model uses an iterative technique of sweeping process for load flow and optimization of DG and its allocation with the minimum loss as an objective function. The constraints considered are voltage regulation limit and DG capacities. The proposed methodology is demonstrated for a IEEE– 15 bus and IEEE–33 bus system and further used for DG allocation planning for Bhaktapur–Balaju 21 bus system. It was found that, PSO is superior in computational speed, time and accuracy and ability to find the optimal solution of DG allocation.
Papers by Ashish Shrestha
Energies, 2021
With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the ... more With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the electrical power systems are facing the problem of transient stability since the PEC based technologies do not contribute to the system inertia, and the proportion of synchronous generators (i.e., the source of inertia) is in decreasing rate. In addition, PEC based technologies’ components have poor inherent damping. It is very important to analyze the system characteristics of a power system to minimize the potential instabilities during the contingencies. This paper presents the parametric sensitivity analysis of the rotor angle stability indicators for the 39-bus New England power system. The indicators of rotor angle stability analysis such as critical fault clearing time (CCT), Eigenvalue points, damping ratio, frequency deviation, voltage deviation, and generator’s speed deviation are identified and analyzed for three case scenarios; each scenario has six sub-cases with different i...
Infrastructure development and rapid urbanization all over the world make cement industries one o... more Infrastructure development and rapid urbanization all over the world make cement industries one of the fastest growing industries. Cement industries are energy intensive, and they contribute significantly to national employment and gross domestic production. In Nepal, 77 cement industries are registered so far, making cement one of the most important sectors for Nepalese economy. This work reviews the history, current technological status, energy consumption pattern, environmental impacts, and economic impacts of cement industries in Nepal and compares the energy consumption in Nepalese cement industries with the rest of the world. Udayapur Cement Industries Limited (UCIL), a government owned cement plant with a design capacity of 800 tpd is taken as a case study. UCIL’s data of energy consumption, production, and maintenance practices are studied and compared with national standards and foreign countries standards. The average specific energy consumption of Nepalese cement industri...
Energies, 2021
Withthe massive penetration of electronic power converter (EPC)-based technologies, numerous issu... more Withthe massive penetration of electronic power converter (EPC)-based technologies, numerous issues are being noticed in the modern power system that may directly affect system dynamics and operational security. The estimation of system performance parameters is especially important for transmission system operators (TSOs) in order to operate a power system securely. This paper presents a Bayesian model to forecast short-term kinetic energy time series data for a power system, which can thus help TSOs to operate a respective power system securely. A Markov chain Monte Carlo (MCMC) method used as a No-U-Turn sampler and Stan’s limited-memory Broyden–Fletcher–Goldfarb–Shanno (LM-BFGS) algorithm is used as the optimization method here. The concept of decomposable time series modeling is adopted to analyze the seasonal characteristics of datasets, and numerous performance measurement matrices are used for model validation. Besides, an autoregressive integrated moving average (ARIMA) mod...
Journal of Renewable Energy, Electrical, and Computer Engineering, 2021
Energy loss (losses) is the loss of a certain amount of energy generated when it is distributed t... more Energy loss (losses) is the loss of a certain amount of energy generated when it is distributed to consumers so that it affects the profitability of the company concerned. The size of the losses from an electric power system shows the level of efficiency of the system, the lower the percentage of losses that occur the more efficient the system. Energy losses in the distribution network are generally divided into two, namely technical and non-technical losses. The calculation of technical losses in the 20 KV medium distribution network of PT PLN (Persero) Ulp Matang Glumpang Dua is carried out using the load curve approach method and using the help of the Microsoft Exel program, while the technical losses calculated are technical losses on the Medium Voltage Network and Distribution Transformer. From the results of the analysis of the calculation of technical losses in 2020, the total technical loss value at MG-01 Matang City is in the range of 13.8% to 20.8% which consists of the av...
Energy Reports, 2021
This paper discusses the current state of DC distribution system, how it can be beneficial to iso... more This paper discusses the current state of DC distribution system, how it can be beneficial to isolate solar-based Micro-Grid (MG) system in a rural area, and how the priority-based approach can help the MGs to operate in cost-effective and reliable ways. DC distribution system holds many advantages over AC systems in such area, where the load demand is not so high and the electricity supply through grid extension is not feasible. Direct load control-based approach can ensure a continuous supply of power to the loads with various priorities. In this paper, an experimental analysis of the DC MGs has been presented with the help of priority based algorithms. A cost-effective SCADA system is developed to interface with the remaining parts of the system, so that the MGs can be monitor and control to get the desired performance. The main objective of this study is to identify a cost-effective and practical energy management system for the rural area, where expensive and advanced technology is not suitable. From this study, it is concluded that the proposed combination of algorithm and SCADA system increase the system's reliability and power consistency significantly.
IEEE Access, 2019
Energy Resources (DERs) are being integrated into the power market by customers rather than large... more Energy Resources (DERs) are being integrated into the power market by customers rather than large scale energy suppliers, thereby slowly transforming the centralized, unidirectional market to a decentralized, bidirectional market and transitioning customers into prosumers. Various system architectures are used in the real field to coordinate the energy distribution in the micro/ mini-grids integrated with DERs, all of which have their strengths, weaknesses and challenges. Peer-to-peer (P2P) is an emerging architecture in the field of electrical energy trading and Distributed Generation (DG) management that can be applied in local energy markets. This paper focuses on P2P energy trading, with an in-depth discussion on its various operating algorithms, their principles, characteristics, features and scope through state of art review on P2P. Furthermore, the energy system of Nepal is used as a case study in this paper, and the micro/mini-grids of Nepal and their associated challenges, constraints and opportunities for improvement are discussed. Finally, an energy trading model is proposed to address the problems occurring in the specific case of Nepalese energy market.
Journal of Asian Electric Vehicles, 2018
Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicul... more Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicular world with improved efficiency but its main issue has been its energy management and supervisory control that ensures best energy distribution. This research analyzes the drive performances of different possible regeneration paths with standard drive cycles through hybrid powertrain model based on quasi-state model of machines. Further, the efficiency map table developed from laboratory test is utilized to estimate efficiency and energy loss in the motor. In this research, 65 kW generator and 110 kW motor of 3000 rpm with an efficiency map are utilized to develop a model in MATLAB. From the simulation result, it has been observed that fuel economy and final state of charge (SOC) of the battery improves when regeneration is done by both machines. The implementation of Rule-Based algorithm indicates that the battery charges only when Internal Combustion Engine (ICE) operates.
Geotechnical and Geological Engineering, 2012
The shear strength reduction technique is becoming more and more popular to determine the factor-... more The shear strength reduction technique is becoming more and more popular to determine the factor-of-safety for geotechnical constructions, especially for slopes. At present, two in principal different procedures are used to apply the numerical shear strength reduction technique for materials characterised by non-linear failure envelopes, like the Hoek-Brown criterion. One procedure is based on the determination on local stress and strength values, whereas the other is based on a global linearization of the non-linear failure envelope. This article shortly describes and discusses these two different procedures and compares results for a broad spectrum of parameter constellations based on slope stability calculations. The local approach is physically more correct. The global approach can be considered as a first approximation. A comparison of both methods reveal that the global approach in comparison to the local approach, can leads to a deviation of up to 15 % in both directions. If one considers the local approach as the 'correct' one, depending on the parameters the results of the global approach can lie on the safe or unsafe site. The practical conclusion is that evaluation of slope stability using the global approach can result in uneconomic slope design or overestimation of safety margin. The use of the local approach instead of the global should be preferred. In case of small safety margins (e.g. 20 % or less) the use of the local approach is strictly recommended.
International Journal of Precision Engineering and Manufacturing-Green Technology, 2020
A majority of Nepalese population are living in rural areas, where the electricity access by grid... more A majority of Nepalese population are living in rural areas, where the electricity access by grid extension is not feasible. Development of micro-hydropower in the isolated state is one of the solutions to provide the electricity to these areas. However, the micro-hydro systems are facing numerous challenges, such as high investment cost, low reliability, low load factor and protection issues. For this reason, the concept of mini-grid has been developed to address the discussed challenges. In this study, a case study of a mini-grid, which is formed by interconnecting six isolated Micro Hydropower Plants (MHPs) with an installed capacity of 107 kW at a transmission voltage of 11 kV, is considered. This study performs the technical and financial analysis, to study the possibility for scaling up the system. Based on different factors, optimum models have been selected, considering a numbers of different cases including cost-benefit and sensitivity analysis. The mini-grid connection of several isolated MHPs is technically possible, but the financial feasibility depends upon various factors, such as the distance between the MHPs, end-use promotion, total capacity of MHPs, future load growth, promotion mechanisms, power trading with utility, etc. The findings show that sustainable operation of mini-grid requires the local capacity building, coordination, and understanding among community cooperatives.
International Journal of Electrical Power & Energy Systems
IEEE Access
Solar Photovoltaic System (SPV) is one of the growing green energy sources having immense penetra... more Solar Photovoltaic System (SPV) is one of the growing green energy sources having immense penetration in the national grid as well as the off-grid around the globe. Regardless of different solar insolation level at various regions of the world, SPV performance is also affected by several factors: conversion efficiency of PV cell technology, ambient temperature and humidity, soiling and seasonal/weather patterns. The rise in PV cell temperature and soiling is found to be detrimental issues regarding power plant performance and life expectancy leading alterations in the levelised cost of energy (LCoE). In this paper, authors present a short glance about factors affecting the performance of photovoltaic modules and re-discuss their usability in cleaning intervention decision-making models. With some highlights on the essence of cleaning to mitigate the soiling issues in PV power plants, this paper presents the existing cleaning techniques and practices along with their evaluations. The need for an optimal cleaning intervention by using advanced scientific tools rather than by visual inspection is drawing the attention of PV experts. The authors finally suggest a schematic of a decision-making model which involves the use of probable parameters, data processing techniques and machine learning tools. The implementation of data science and machine learning in a solar PV panel cleaning system could be a remarkable advancement in the field of renewable energy.
Electronics
Accompanying the advancement on the Internet of Things (IoT), the concept of remote monitoring an... more Accompanying the advancement on the Internet of Things (IoT), the concept of remote monitoring and control using IoT devices is becoming popular. Digital smart meters hold many advantages over traditional analog meters, and smart metering is one of application of IoT technology. It supports the conventional power system in adopting modern concepts like smart grids, block-chains, automation, etc. due to their remote load monitoring and control capabilities. However, in many applications, the traditional analog meters still are preferred over digital smart meters due to the high deployment and operating costs, and the unreliability of the smart meters. The primary reasons behind these issues are a lack of a reliable and affordable communication system, which can be addressed by the deployment of a dedicated network formed with a Low Power Wide Area (LPWA) platform like wireless radio standards (i.e., LoRa devices). This paper discusses LoRa technology and its implementation to solve t...
The Journal of Engineering
IEEE Access
Nepal is a Himalayan country with its 83% of its geography being composed of hills and mountains.... more Nepal is a Himalayan country with its 83% of its geography being composed of hills and mountains. Around 22% of the Nepalese population is not receiving electricity through the national power utility and is forced to identify alternative approaches to electrification. The Micro/Mini-Grid (MG) system is one of the promising approaches in terms of cost, reliability and performance for rural electrification, where electrification through national power utility is not techno-economically feasible. However, various issues must be identified and considered during the implementation of MGs in a rural community. In this paper, numerous technical, social and management issues are identified and discussed relating to the implementation and operation of reliable and stable MGs in the Himalayas. To our knowledge, this is the first scientific work that presents a comprehensive review of Himalayan MGs and their associated elements. This article reviews the available research articles, project documents, and Government reports on MG development, from which a clear roadmap is constructed. From the comprehensive study, it is observed that the existing MGs are not adequately designed for the specific area, considering the local resources and local information. Based on the identified issues, some practical and efficient recommendations have been made, so that future MG projects will address the possible problems during the design and implementation phase. INDEX TERMS Control management, distribute generation system, isolated energy system, mini-grid, rural electrification.
IOP Conference Series: Earth and Environmental Science
International Journal of Precision Engineering and Manufacturing-Green Technology
A majority of Nepalese population are living in rural areas, where the electricity access by grid... more A majority of Nepalese population are living in rural areas, where the electricity access by grid extension is not feasible. Development of micro-hydropower in the isolated state is one of the solutions to provide the electricity to these areas. However, the micro-hydro systems are facing numerous challenges, such as high investment cost, low reliability, low load factor and protection issues. For this reason, the concept of mini-grid has been developed to address the discussed challenges. In this study, a case study of a mini-grid, which is formed by interconnecting six isolated Micro Hydropower Plants (MHPs) with an installed capacity of 107 kW at a transmission voltage of 11 kV, is considered. This study performs the technical and financial analysis, to study the possibility for scaling up the system. Based on different factors, optimum models have been selected, considering a numbers of different cases including cost--benefit and sensitivity analysis. The mini-grid connection of...
With the increasing demand for renewable energy, solar photovoltaic technology is being a topic o... more With the increasing demand for renewable energy, solar photovoltaic technology is being a topic of concern. However, due to the accumulation of dust and dirt over the panel surface, the performance of the photovoltaic system degrades to a noticeable number. To address this issue: a fully automated, cost worthy and efficient system needs to be invented. This paper presents the design and fabrication process of a prototype able to clean the panel surface. The prototype of this system comprises of a cleaning robot and a cloud interface: the cleaning robot is mobile and able to clean the entire solar array back and forth, with its separately driven cleaning rotatory brush; whereas, the cloud interface is a human-machine interface featuring the distant monitoring and control of the robot. Additionally, to notify the performance of distantly placed solar farm, a sensing unit consisting of sensors was added to this system. Furthermore, to add an automatic cleaning feature, a month-long data of totally clean and dusty panel was processed with regression analysis, and the developed regression model was programmed into the sensing unit. The sensing unit added with the regression model is named as an autonomous unit, as it predicts the suitable time for cleaning action. According to the system evaluation done on a demonstration PV module, it was found that the designed system can clean dry dust accumulated over the panel's surface. Moreover, by attaching the metal rail tracks on a long solar array, the system seems to be implementable on a large scale solar farm.
A Particle Swarm Optimization (PSO) method is proposed for the optimal allocation of Distributed ... more A Particle Swarm Optimization (PSO) method is proposed for the optimal allocation of Distributed Generation (DG) in the radial distribution system (RDS) for voltage profile improvement. The proposed model uses an iterative technique of sweeping process for load flow and optimization of DG and its allocation with the minimum loss as an objective function. The constraints considered are voltage regulation limit and DG capacities. The proposed methodology is demonstrated for a IEEE– 15 bus and IEEE–33 bus system and further used for DG allocation planning for Bhaktapur–Balaju 21 bus system. It was found that, PSO is superior in computational speed, time and accuracy and ability to find the optimal solution of DG allocation.
Energies, 2021
With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the ... more With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the electrical power systems are facing the problem of transient stability since the PEC based technologies do not contribute to the system inertia, and the proportion of synchronous generators (i.e., the source of inertia) is in decreasing rate. In addition, PEC based technologies’ components have poor inherent damping. It is very important to analyze the system characteristics of a power system to minimize the potential instabilities during the contingencies. This paper presents the parametric sensitivity analysis of the rotor angle stability indicators for the 39-bus New England power system. The indicators of rotor angle stability analysis such as critical fault clearing time (CCT), Eigenvalue points, damping ratio, frequency deviation, voltage deviation, and generator’s speed deviation are identified and analyzed for three case scenarios; each scenario has six sub-cases with different i...
Infrastructure development and rapid urbanization all over the world make cement industries one o... more Infrastructure development and rapid urbanization all over the world make cement industries one of the fastest growing industries. Cement industries are energy intensive, and they contribute significantly to national employment and gross domestic production. In Nepal, 77 cement industries are registered so far, making cement one of the most important sectors for Nepalese economy. This work reviews the history, current technological status, energy consumption pattern, environmental impacts, and economic impacts of cement industries in Nepal and compares the energy consumption in Nepalese cement industries with the rest of the world. Udayapur Cement Industries Limited (UCIL), a government owned cement plant with a design capacity of 800 tpd is taken as a case study. UCIL’s data of energy consumption, production, and maintenance practices are studied and compared with national standards and foreign countries standards. The average specific energy consumption of Nepalese cement industri...
Energies, 2021
Withthe massive penetration of electronic power converter (EPC)-based technologies, numerous issu... more Withthe massive penetration of electronic power converter (EPC)-based technologies, numerous issues are being noticed in the modern power system that may directly affect system dynamics and operational security. The estimation of system performance parameters is especially important for transmission system operators (TSOs) in order to operate a power system securely. This paper presents a Bayesian model to forecast short-term kinetic energy time series data for a power system, which can thus help TSOs to operate a respective power system securely. A Markov chain Monte Carlo (MCMC) method used as a No-U-Turn sampler and Stan’s limited-memory Broyden–Fletcher–Goldfarb–Shanno (LM-BFGS) algorithm is used as the optimization method here. The concept of decomposable time series modeling is adopted to analyze the seasonal characteristics of datasets, and numerous performance measurement matrices are used for model validation. Besides, an autoregressive integrated moving average (ARIMA) mod...
Journal of Renewable Energy, Electrical, and Computer Engineering, 2021
Energy loss (losses) is the loss of a certain amount of energy generated when it is distributed t... more Energy loss (losses) is the loss of a certain amount of energy generated when it is distributed to consumers so that it affects the profitability of the company concerned. The size of the losses from an electric power system shows the level of efficiency of the system, the lower the percentage of losses that occur the more efficient the system. Energy losses in the distribution network are generally divided into two, namely technical and non-technical losses. The calculation of technical losses in the 20 KV medium distribution network of PT PLN (Persero) Ulp Matang Glumpang Dua is carried out using the load curve approach method and using the help of the Microsoft Exel program, while the technical losses calculated are technical losses on the Medium Voltage Network and Distribution Transformer. From the results of the analysis of the calculation of technical losses in 2020, the total technical loss value at MG-01 Matang City is in the range of 13.8% to 20.8% which consists of the av...
Energy Reports, 2021
This paper discusses the current state of DC distribution system, how it can be beneficial to iso... more This paper discusses the current state of DC distribution system, how it can be beneficial to isolate solar-based Micro-Grid (MG) system in a rural area, and how the priority-based approach can help the MGs to operate in cost-effective and reliable ways. DC distribution system holds many advantages over AC systems in such area, where the load demand is not so high and the electricity supply through grid extension is not feasible. Direct load control-based approach can ensure a continuous supply of power to the loads with various priorities. In this paper, an experimental analysis of the DC MGs has been presented with the help of priority based algorithms. A cost-effective SCADA system is developed to interface with the remaining parts of the system, so that the MGs can be monitor and control to get the desired performance. The main objective of this study is to identify a cost-effective and practical energy management system for the rural area, where expensive and advanced technology is not suitable. From this study, it is concluded that the proposed combination of algorithm and SCADA system increase the system's reliability and power consistency significantly.
IEEE Access, 2019
Energy Resources (DERs) are being integrated into the power market by customers rather than large... more Energy Resources (DERs) are being integrated into the power market by customers rather than large scale energy suppliers, thereby slowly transforming the centralized, unidirectional market to a decentralized, bidirectional market and transitioning customers into prosumers. Various system architectures are used in the real field to coordinate the energy distribution in the micro/ mini-grids integrated with DERs, all of which have their strengths, weaknesses and challenges. Peer-to-peer (P2P) is an emerging architecture in the field of electrical energy trading and Distributed Generation (DG) management that can be applied in local energy markets. This paper focuses on P2P energy trading, with an in-depth discussion on its various operating algorithms, their principles, characteristics, features and scope through state of art review on P2P. Furthermore, the energy system of Nepal is used as a case study in this paper, and the micro/mini-grids of Nepal and their associated challenges, constraints and opportunities for improvement are discussed. Finally, an energy trading model is proposed to address the problems occurring in the specific case of Nepalese energy market.
Journal of Asian Electric Vehicles, 2018
Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicul... more Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicular world with improved efficiency but its main issue has been its energy management and supervisory control that ensures best energy distribution. This research analyzes the drive performances of different possible regeneration paths with standard drive cycles through hybrid powertrain model based on quasi-state model of machines. Further, the efficiency map table developed from laboratory test is utilized to estimate efficiency and energy loss in the motor. In this research, 65 kW generator and 110 kW motor of 3000 rpm with an efficiency map are utilized to develop a model in MATLAB. From the simulation result, it has been observed that fuel economy and final state of charge (SOC) of the battery improves when regeneration is done by both machines. The implementation of Rule-Based algorithm indicates that the battery charges only when Internal Combustion Engine (ICE) operates.
Geotechnical and Geological Engineering, 2012
The shear strength reduction technique is becoming more and more popular to determine the factor-... more The shear strength reduction technique is becoming more and more popular to determine the factor-of-safety for geotechnical constructions, especially for slopes. At present, two in principal different procedures are used to apply the numerical shear strength reduction technique for materials characterised by non-linear failure envelopes, like the Hoek-Brown criterion. One procedure is based on the determination on local stress and strength values, whereas the other is based on a global linearization of the non-linear failure envelope. This article shortly describes and discusses these two different procedures and compares results for a broad spectrum of parameter constellations based on slope stability calculations. The local approach is physically more correct. The global approach can be considered as a first approximation. A comparison of both methods reveal that the global approach in comparison to the local approach, can leads to a deviation of up to 15 % in both directions. If one considers the local approach as the 'correct' one, depending on the parameters the results of the global approach can lie on the safe or unsafe site. The practical conclusion is that evaluation of slope stability using the global approach can result in uneconomic slope design or overestimation of safety margin. The use of the local approach instead of the global should be preferred. In case of small safety margins (e.g. 20 % or less) the use of the local approach is strictly recommended.
International Journal of Precision Engineering and Manufacturing-Green Technology, 2020
A majority of Nepalese population are living in rural areas, where the electricity access by grid... more A majority of Nepalese population are living in rural areas, where the electricity access by grid extension is not feasible. Development of micro-hydropower in the isolated state is one of the solutions to provide the electricity to these areas. However, the micro-hydro systems are facing numerous challenges, such as high investment cost, low reliability, low load factor and protection issues. For this reason, the concept of mini-grid has been developed to address the discussed challenges. In this study, a case study of a mini-grid, which is formed by interconnecting six isolated Micro Hydropower Plants (MHPs) with an installed capacity of 107 kW at a transmission voltage of 11 kV, is considered. This study performs the technical and financial analysis, to study the possibility for scaling up the system. Based on different factors, optimum models have been selected, considering a numbers of different cases including cost-benefit and sensitivity analysis. The mini-grid connection of several isolated MHPs is technically possible, but the financial feasibility depends upon various factors, such as the distance between the MHPs, end-use promotion, total capacity of MHPs, future load growth, promotion mechanisms, power trading with utility, etc. The findings show that sustainable operation of mini-grid requires the local capacity building, coordination, and understanding among community cooperatives.
International Journal of Electrical Power & Energy Systems
IEEE Access
Solar Photovoltaic System (SPV) is one of the growing green energy sources having immense penetra... more Solar Photovoltaic System (SPV) is one of the growing green energy sources having immense penetration in the national grid as well as the off-grid around the globe. Regardless of different solar insolation level at various regions of the world, SPV performance is also affected by several factors: conversion efficiency of PV cell technology, ambient temperature and humidity, soiling and seasonal/weather patterns. The rise in PV cell temperature and soiling is found to be detrimental issues regarding power plant performance and life expectancy leading alterations in the levelised cost of energy (LCoE). In this paper, authors present a short glance about factors affecting the performance of photovoltaic modules and re-discuss their usability in cleaning intervention decision-making models. With some highlights on the essence of cleaning to mitigate the soiling issues in PV power plants, this paper presents the existing cleaning techniques and practices along with their evaluations. The need for an optimal cleaning intervention by using advanced scientific tools rather than by visual inspection is drawing the attention of PV experts. The authors finally suggest a schematic of a decision-making model which involves the use of probable parameters, data processing techniques and machine learning tools. The implementation of data science and machine learning in a solar PV panel cleaning system could be a remarkable advancement in the field of renewable energy.
Electronics
Accompanying the advancement on the Internet of Things (IoT), the concept of remote monitoring an... more Accompanying the advancement on the Internet of Things (IoT), the concept of remote monitoring and control using IoT devices is becoming popular. Digital smart meters hold many advantages over traditional analog meters, and smart metering is one of application of IoT technology. It supports the conventional power system in adopting modern concepts like smart grids, block-chains, automation, etc. due to their remote load monitoring and control capabilities. However, in many applications, the traditional analog meters still are preferred over digital smart meters due to the high deployment and operating costs, and the unreliability of the smart meters. The primary reasons behind these issues are a lack of a reliable and affordable communication system, which can be addressed by the deployment of a dedicated network formed with a Low Power Wide Area (LPWA) platform like wireless radio standards (i.e., LoRa devices). This paper discusses LoRa technology and its implementation to solve t...
The Journal of Engineering
IEEE Access
Nepal is a Himalayan country with its 83% of its geography being composed of hills and mountains.... more Nepal is a Himalayan country with its 83% of its geography being composed of hills and mountains. Around 22% of the Nepalese population is not receiving electricity through the national power utility and is forced to identify alternative approaches to electrification. The Micro/Mini-Grid (MG) system is one of the promising approaches in terms of cost, reliability and performance for rural electrification, where electrification through national power utility is not techno-economically feasible. However, various issues must be identified and considered during the implementation of MGs in a rural community. In this paper, numerous technical, social and management issues are identified and discussed relating to the implementation and operation of reliable and stable MGs in the Himalayas. To our knowledge, this is the first scientific work that presents a comprehensive review of Himalayan MGs and their associated elements. This article reviews the available research articles, project documents, and Government reports on MG development, from which a clear roadmap is constructed. From the comprehensive study, it is observed that the existing MGs are not adequately designed for the specific area, considering the local resources and local information. Based on the identified issues, some practical and efficient recommendations have been made, so that future MG projects will address the possible problems during the design and implementation phase. INDEX TERMS Control management, distribute generation system, isolated energy system, mini-grid, rural electrification.
IOP Conference Series: Earth and Environmental Science
International Journal of Precision Engineering and Manufacturing-Green Technology
A majority of Nepalese population are living in rural areas, where the electricity access by grid... more A majority of Nepalese population are living in rural areas, where the electricity access by grid extension is not feasible. Development of micro-hydropower in the isolated state is one of the solutions to provide the electricity to these areas. However, the micro-hydro systems are facing numerous challenges, such as high investment cost, low reliability, low load factor and protection issues. For this reason, the concept of mini-grid has been developed to address the discussed challenges. In this study, a case study of a mini-grid, which is formed by interconnecting six isolated Micro Hydropower Plants (MHPs) with an installed capacity of 107 kW at a transmission voltage of 11 kV, is considered. This study performs the technical and financial analysis, to study the possibility for scaling up the system. Based on different factors, optimum models have been selected, considering a numbers of different cases including cost--benefit and sensitivity analysis. The mini-grid connection of...
With the increasing demand for renewable energy, solar photovoltaic technology is being a topic o... more With the increasing demand for renewable energy, solar photovoltaic technology is being a topic of concern. However, due to the accumulation of dust and dirt over the panel surface, the performance of the photovoltaic system degrades to a noticeable number. To address this issue: a fully automated, cost worthy and efficient system needs to be invented. This paper presents the design and fabrication process of a prototype able to clean the panel surface. The prototype of this system comprises of a cleaning robot and a cloud interface: the cleaning robot is mobile and able to clean the entire solar array back and forth, with its separately driven cleaning rotatory brush; whereas, the cloud interface is a human-machine interface featuring the distant monitoring and control of the robot. Additionally, to notify the performance of distantly placed solar farm, a sensing unit consisting of sensors was added to this system. Furthermore, to add an automatic cleaning feature, a month-long data of totally clean and dusty panel was processed with regression analysis, and the developed regression model was programmed into the sensing unit. The sensing unit added with the regression model is named as an autonomous unit, as it predicts the suitable time for cleaning action. According to the system evaluation done on a demonstration PV module, it was found that the designed system can clean dry dust accumulated over the panel's surface. Moreover, by attaching the metal rail tracks on a long solar array, the system seems to be implementable on a large scale solar farm.
Hybrid Power System (HPS) is an energy system with combination of different regenerative energy s... more Hybrid Power System (HPS) is an energy system with combination of different regenerative energy sources like Solar, Wind, Geo-Thermal, Biomass and several others to achieve energy sustainability. This paper investigates the feasibility of grid connected and stand-alone hybrid energy system to meet electric load requirement of a community or organization, by utilizing the available resources. Potentiality of different energy sources like solar, wind, bio-gas, etc. along with currently used energy sources is studied thoroughly by taking a case study of Kathmandu University central campus, located at Dhulikhel, Nepal. Technical and economic analysis of on-grid and off-grid hybrid system is performed to get optimum model that supply continuous energy to the end user. Furthermore, the possibility of net metering with national utility has been analysed. The main objective of this study is to identify the suitable energy mixed model, that provide the sustainable energy supply to the university, and recommend the possible energy generators to be added for fulfilling the continuously increasing load demand. The load profile of several years of the University is taken into consideration for forecasting the power demand. The findings of the research show that system when adopted to hybrid system can meet up to 55% of the load by renewable resources. Maximum renewable fraction is found to be 0.603 and maximum renewable penetration of 812%.
Journal of Asian Electric Vehicles, 2018
Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicul... more Hybrid Electric Vehicle (HEV) is one of the emerging environment-friendly technologies in vehicular world with improved efficiency but its main issue has been its energy management and supervisory control that ensures best energy distribution. This research analyzes the drive performances of different possible regeneration paths with standard drive cycles through hybrid powertrain model based on quasi-state model of machines. Further, the efficiency map table developed from laboratory test is utilized to estimate efficiency and energy loss in the motor. In this research, 65 kW generator and 110 kW motor of 3000 rpm with an efficiency map are utilized to develop a model in MATLAB. From the simulation result, it has been observed that fuel economy and final state of charge (SOC) of the battery improves when regeneration is done by both machines. The implementation of Rule-Based algorithm indicates that the battery charges only when Internal Combustion Engine (ICE) operates. Keywords hybrid electric vehicle, electric vehicle, internal combustion engine, state of charge, drive cycle 1. INTRODUCTION Hybrid Electric Vehicles (HEV) has become a promising technology for public and mass transport when compared to the low efficient conventional vehicles. Fossil fuel-based vehicles have become the main reason for the accelerated depletion of the non-renewable energy resources in an unsustainable manner. ICE based vehicle or classical vehicle has a maximum efficiency of around 40 % [Eshani et al., 2018] for a particular operating condition, but in reality, the vehicle requires a wide range of torque and speed. The output power drive thus varies and it will only have a maximum rating for a small interval of time, resulting in the requirement of the oversized engine. Electric Vehicles (EV) has high efficiency as the converter loss and machine loss are negligible and also with the implementation of the converter, the operating region can be tailored. Besides that, EV is environmentally friendly and there is the possibility of regeneration as well. Total recovered energy for EV is around 20% [Cauwer et al., 2015], but it has some limitation such as; high charging time and short mileage compared to the classical one [Wang, 2016]. The advent of permanent magnet (PM) material and Neodymium-Iron-Boron (Nd-Fe-B) with higher en
5th International Conference on Developments in Renewable Energy Technology, 2018
This study presents techno-economic analysis that compares the isolated and grid-connected Micro-... more This study presents techno-economic analysis that compares the isolated and grid-connected Micro-hydropower plant (MHP) for sustainable rural electrification. The critical factors that need to be considered in order to analyze the MHP are characterized, and the risk analysis is performed by evaluating the probability of the Net Present Value (NPV), Internal Rate of Return (IRR), Benefit to Cost ratio (B/C), and Profitability. Furthermore, technical analysis is done by performing the load flow analysis of the system for different case scenario. It is found that the project is not feasible even for private investment under subsidy rate. However, the profitability of the grid-connected system depends upon various factors such as tariff rate, load factor, amount of load, power trading with utility.