ENOCK MULENGA | Luleå University of Technology (original) (raw)

Papers by ENOCK MULENGA

Research paper thumbnail of Windows of Opportunities: Orientation, Sizing and PV-Shading of the Glazed Area to Reduce Cooling Energy Demand in Sub-Sahara Africa

Energies, Apr 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Assessing the Impacts of a cyber-attack-Induced Uncontrolled EV Charging in Zambia

Zenodo (CERN European Organization for Nuclear Research), Sep 3, 2023

Research paper thumbnail of Assessing aspects of solution-based chemical synthesis to convert waste Si solar cells into nanostructured aluminosilicate crystals

Research paper thumbnail of Windows of Opportunities: Orientation, Sizing and PV-Shading of the Glazed Area to Reduce Cooling Energy Demand in Sub-Sahara Africa

Energies, Apr 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Multiple distribution networks hosting capacity assessment using a stochastic approach

Sustainable Energy, Grids and Networks

Research paper thumbnail of Power Quality Issues of Electro-Mobility on Distribution Network—An Overview

Energies

The journey towards sustainable transportation has significantly increased the grid penetration o... more The journey towards sustainable transportation has significantly increased the grid penetration of electric vehicles (EV) around the world. The connection of EVs to the power grid poses a series of new challenges for network operators, such as network loading, voltage profile perturbation, voltage unbalance, and other power quality issues. This paper presents a coalescence of knowledge on the impact that electro-mobility can impose on the grid, and identifies gaps for further research. Further, the study investigates the impact of electric vehicle charging on the medium-voltage network and low-voltage distribution network, keeping in mind the role of network operators, utilities, and customers. From this, the impacts, challenges, and recommendations are summarized. This paper will be a valuable resource to research entities, industry professionals, and network operators, as a ready reference of all possible power quality challenges posed by electro-mobility on the distribution network.

Research paper thumbnail of Solar PV Stochastic Hosting Capacity Assessment Considering Epistemic (E) Probability Distribution Function (PDF)

Electricity, Dec 5, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Floating Solar Photovoltaic (FSPV) Potential in Zambia: Case Studies on Six Hydropower Power Plant Reservoirs

Research paper thumbnail of Techno-economic analysis of off-grid PV-Diesel power generation system for rural electrification: A case study of Chilubi district in Zambia

Research paper thumbnail of Fuel Cell Technology: An Optional Back-Up Power Supply System for Zambia

Fuel cell technology is slowly growing in other countries and is being used for power production.... more Fuel cell technology is slowly growing in other countries and is being used for power production. In Zambia, the technology is yet to penetrate. The increase in power demand at a time of poor rainfall patterns entail diversification to other power sources. This paper presents knowledge on fuel cell technology, types, applications, sample simulation and its adaptation to Zambia as back-up power supply from literature, applied systems and simulation set-up in matlab-simulink. Massive investment in solar technology, rise in fuel prices for diesel generators and possibility of combining fuel cell with photovoltaics or as storage to store away variability has necessitated the review of this technology as an optional back-up power supply for Zambia. The sample simulation of a 6 kW fuel cell system in Matlab showed results of dc power. The same power type from PV array before power conditioning. Fuel cell technology exist in different types due electrolyte used. These are proton exchange m...

Research paper thumbnail of The Importance of Power Quality Monitoring for Modern Network Operators and Industries in Zambia

Modern electricity networks contain a mixture of different types of loads all of which affect the... more Modern electricity networks contain a mixture of different types of loads all of which affect the voltage one way or the other. They can either improve or deteriorate the so-called “voltage quality”, also known as “power quality” or “quality of power” that is being supplied by network operators and received by their customers. Increased use of power electronic devices for the control of rotating electrical machines and the presence of sensitive electronic equipment has further affected the power quality. The impact of new equipment is rarely an improvement, although it is often less than feared at first. The shortage of rainfall has resulted in a lot of investment in solar photovoltaics power, which has the potential to further worsening the power quality in the Zambian power network. To quantify the impact of these and other changes on the power quality requires monitoring of voltage and current with high accuracy and time resolution. The results of such a power-quality monitoring ...

Research paper thumbnail of On the hosting capacity of distribution networks for solar power

The future will bring changes in energy production and consumption that will affect the performan... more The future will bring changes in energy production and consumption that will affect the performance of electricity distribution networks. Electric vehicle charging will increase consumption; the installation of solar photovoltaic (PV) units will increase production. Both will change the energy flow and affect the power quality. The installation of solar PV units or electric vehicle (EV) charging has a limit above, which they unacceptably deteriorate the distribution networks' performance. This limit is referred to as the hosting capacity of the distribution network. This work is about developing, applying and studying methods for estimating the hosting capacity, especially solar PV. Three fundamentally different methods to estimate solar PV hosting capacity for single-phase and three-phase units have been identified by a detailed review of the literature: deterministic, stochastic and time-series. The methods were shown to differ in the required input data, accuracy, computatio...

Research paper thumbnail of Overvoltage due to single-phase and three-phase connected PV

25th International Conference on Electricity Distribution, Madrid, 3-6 June 2019., 2019

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A stochastic approach is applied to a 28-customer low-voltage network and the probability of overvoltage is assessed. It is shown that the voltage rise due to single-phase connected PV is six times the rise for three-phase connected PV. To mitigate the overvoltage, grid-reinforcement, reactive power compensation, curtailment and coordinated connection of PV can be used. It is shown that reactive compensation is not effective in LV grids due to high R/X ratio. Coordinated connection helps in reducing the overvoltages caused by single-phase PV. Policy suggestions towards three-phase PV installations and coordinated single-phase PV connections are included in the paper.

Research paper thumbnail of Limits set by component loadability on solar power integration in distribution networks

Electric Power Systems Research, 2022

Research paper thumbnail of Solar PV hosting capacity methods and industrial application gaps

CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution

Research paper thumbnail of Likelihood of Overload due to connected Solar PV

CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution

Research paper thumbnail of Department-Electrics

Impacts of integrating solar PV power to an existing grid Case Studies of Mölndal and Orust energ... more Impacts of integrating solar PV power to an existing grid Case Studies of Mölndal and Orust energy distribution (10/0.4 kV and 130/10 kV) grids Master’s thesis in Electric Power Engineering

Research paper thumbnail of Overvoltage Due to Single and Three-Phase Connected PV

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A stochastic approach is applied to a 28-customer low-voltage network and the probability of overvoltage is assessed. It is shown that the voltage rise due to single-phase connected PV is six times the rise for three-phase connected PV. To mitigate the overvoltage, grid-reinforcement, reactive power compensation, curtailment and coordinated connection of PV can be used. It is shown that reactive compensation is not effective in LV grids due to high R/X ratio. Coordinated connection helps in reducing the overvoltages caused by single-phase PV. Policy suggestions towards three-phase PV installations and coordinated single-phase PV connections are included in the paper.

Research paper thumbnail of Impact of service and feeder cable upgrade on hosting capacity for single phase connected photovoltaics

The addition of photovoltaics (PV) to a grid impacts the performance of that grid in a number of ... more The addition of photovoltaics (PV) to a grid impacts the performance of that grid in a number of ways. These impacts limit how much PV can be connected, termed ‘hosting capacity (HC)’. The impacts include overvoltage and overloading. Mitigation of impacts can be achieved in different ways: in this paper, upgrade of service cable and feeder cable has been considered, one of the classical solutions. Cable size upgrades to 16, 25 and 35 mm2 from 10 mm2 have been studied to mitigate overvoltages in a 28-customer Swedish suburban grid. A stochastic planning-based approach has been used to obtain a performance parameter that can be used to compare the mitigation methods. The results showed an improvement in overvoltage and hosting capacity with cable upgrade. The hosting capacity is also shown to be sensitive to the risk chosen and to the PV size.

Research paper thumbnail of Overvoltage due to single-phase and three-phase connected PV and what to do about it

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A ...

Research paper thumbnail of Windows of Opportunities: Orientation, Sizing and PV-Shading of the Glazed Area to Reduce Cooling Energy Demand in Sub-Sahara Africa

Energies, Apr 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Assessing the Impacts of a cyber-attack-Induced Uncontrolled EV Charging in Zambia

Zenodo (CERN European Organization for Nuclear Research), Sep 3, 2023

Research paper thumbnail of Assessing aspects of solution-based chemical synthesis to convert waste Si solar cells into nanostructured aluminosilicate crystals

Research paper thumbnail of Windows of Opportunities: Orientation, Sizing and PV-Shading of the Glazed Area to Reduce Cooling Energy Demand in Sub-Sahara Africa

Energies, Apr 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Multiple distribution networks hosting capacity assessment using a stochastic approach

Sustainable Energy, Grids and Networks

Research paper thumbnail of Power Quality Issues of Electro-Mobility on Distribution Network—An Overview

Energies

The journey towards sustainable transportation has significantly increased the grid penetration o... more The journey towards sustainable transportation has significantly increased the grid penetration of electric vehicles (EV) around the world. The connection of EVs to the power grid poses a series of new challenges for network operators, such as network loading, voltage profile perturbation, voltage unbalance, and other power quality issues. This paper presents a coalescence of knowledge on the impact that electro-mobility can impose on the grid, and identifies gaps for further research. Further, the study investigates the impact of electric vehicle charging on the medium-voltage network and low-voltage distribution network, keeping in mind the role of network operators, utilities, and customers. From this, the impacts, challenges, and recommendations are summarized. This paper will be a valuable resource to research entities, industry professionals, and network operators, as a ready reference of all possible power quality challenges posed by electro-mobility on the distribution network.

Research paper thumbnail of Solar PV Stochastic Hosting Capacity Assessment Considering Epistemic (E) Probability Distribution Function (PDF)

Electricity, Dec 5, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Floating Solar Photovoltaic (FSPV) Potential in Zambia: Case Studies on Six Hydropower Power Plant Reservoirs

Research paper thumbnail of Techno-economic analysis of off-grid PV-Diesel power generation system for rural electrification: A case study of Chilubi district in Zambia

Research paper thumbnail of Fuel Cell Technology: An Optional Back-Up Power Supply System for Zambia

Fuel cell technology is slowly growing in other countries and is being used for power production.... more Fuel cell technology is slowly growing in other countries and is being used for power production. In Zambia, the technology is yet to penetrate. The increase in power demand at a time of poor rainfall patterns entail diversification to other power sources. This paper presents knowledge on fuel cell technology, types, applications, sample simulation and its adaptation to Zambia as back-up power supply from literature, applied systems and simulation set-up in matlab-simulink. Massive investment in solar technology, rise in fuel prices for diesel generators and possibility of combining fuel cell with photovoltaics or as storage to store away variability has necessitated the review of this technology as an optional back-up power supply for Zambia. The sample simulation of a 6 kW fuel cell system in Matlab showed results of dc power. The same power type from PV array before power conditioning. Fuel cell technology exist in different types due electrolyte used. These are proton exchange m...

Research paper thumbnail of The Importance of Power Quality Monitoring for Modern Network Operators and Industries in Zambia

Modern electricity networks contain a mixture of different types of loads all of which affect the... more Modern electricity networks contain a mixture of different types of loads all of which affect the voltage one way or the other. They can either improve or deteriorate the so-called “voltage quality”, also known as “power quality” or “quality of power” that is being supplied by network operators and received by their customers. Increased use of power electronic devices for the control of rotating electrical machines and the presence of sensitive electronic equipment has further affected the power quality. The impact of new equipment is rarely an improvement, although it is often less than feared at first. The shortage of rainfall has resulted in a lot of investment in solar photovoltaics power, which has the potential to further worsening the power quality in the Zambian power network. To quantify the impact of these and other changes on the power quality requires monitoring of voltage and current with high accuracy and time resolution. The results of such a power-quality monitoring ...

Research paper thumbnail of On the hosting capacity of distribution networks for solar power

The future will bring changes in energy production and consumption that will affect the performan... more The future will bring changes in energy production and consumption that will affect the performance of electricity distribution networks. Electric vehicle charging will increase consumption; the installation of solar photovoltaic (PV) units will increase production. Both will change the energy flow and affect the power quality. The installation of solar PV units or electric vehicle (EV) charging has a limit above, which they unacceptably deteriorate the distribution networks' performance. This limit is referred to as the hosting capacity of the distribution network. This work is about developing, applying and studying methods for estimating the hosting capacity, especially solar PV. Three fundamentally different methods to estimate solar PV hosting capacity for single-phase and three-phase units have been identified by a detailed review of the literature: deterministic, stochastic and time-series. The methods were shown to differ in the required input data, accuracy, computatio...

Research paper thumbnail of Overvoltage due to single-phase and three-phase connected PV

25th International Conference on Electricity Distribution, Madrid, 3-6 June 2019., 2019

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A stochastic approach is applied to a 28-customer low-voltage network and the probability of overvoltage is assessed. It is shown that the voltage rise due to single-phase connected PV is six times the rise for three-phase connected PV. To mitigate the overvoltage, grid-reinforcement, reactive power compensation, curtailment and coordinated connection of PV can be used. It is shown that reactive compensation is not effective in LV grids due to high R/X ratio. Coordinated connection helps in reducing the overvoltages caused by single-phase PV. Policy suggestions towards three-phase PV installations and coordinated single-phase PV connections are included in the paper.

Research paper thumbnail of Limits set by component loadability on solar power integration in distribution networks

Electric Power Systems Research, 2022

Research paper thumbnail of Solar PV hosting capacity methods and industrial application gaps

CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution

Research paper thumbnail of Likelihood of Overload due to connected Solar PV

CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution

Research paper thumbnail of Department-Electrics

Impacts of integrating solar PV power to an existing grid Case Studies of Mölndal and Orust energ... more Impacts of integrating solar PV power to an existing grid Case Studies of Mölndal and Orust energy distribution (10/0.4 kV and 130/10 kV) grids Master’s thesis in Electric Power Engineering

Research paper thumbnail of Overvoltage Due to Single and Three-Phase Connected PV

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A stochastic approach is applied to a 28-customer low-voltage network and the probability of overvoltage is assessed. It is shown that the voltage rise due to single-phase connected PV is six times the rise for three-phase connected PV. To mitigate the overvoltage, grid-reinforcement, reactive power compensation, curtailment and coordinated connection of PV can be used. It is shown that reactive compensation is not effective in LV grids due to high R/X ratio. Coordinated connection helps in reducing the overvoltages caused by single-phase PV. Policy suggestions towards three-phase PV installations and coordinated single-phase PV connections are included in the paper.

Research paper thumbnail of Impact of service and feeder cable upgrade on hosting capacity for single phase connected photovoltaics

The addition of photovoltaics (PV) to a grid impacts the performance of that grid in a number of ... more The addition of photovoltaics (PV) to a grid impacts the performance of that grid in a number of ways. These impacts limit how much PV can be connected, termed ‘hosting capacity (HC)’. The impacts include overvoltage and overloading. Mitigation of impacts can be achieved in different ways: in this paper, upgrade of service cable and feeder cable has been considered, one of the classical solutions. Cable size upgrades to 16, 25 and 35 mm2 from 10 mm2 have been studied to mitigate overvoltages in a 28-customer Swedish suburban grid. A stochastic planning-based approach has been used to obtain a performance parameter that can be used to compare the mitigation methods. The results showed an improvement in overvoltage and hosting capacity with cable upgrade. The hosting capacity is also shown to be sensitive to the risk chosen and to the PV size.

Research paper thumbnail of Overvoltage due to single-phase and three-phase connected PV and what to do about it

This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltag... more This paper presents the overvoltage caused by single and three-phase connected PV to a low-voltage distribution grid. Statistics are obtained based on source-impedance data for 40 000 customers. A ...