It is difficult to estimate how much distributed generation (DG) capacity will be connected to di... more It is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years, however, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning and control strategies. The work of this Task Force is focused on the numerous strategies and methods that have been developed in recent years to address DG integration and planning. This paper contains a critical review of the work in this field. Although there have been numerous publications in this area, widespread implementation of the methods has not taken place. The barriers to implementation of the advanced techniques are outlined, highlighting why network operators have been slow to pick up on the research to date. Furthermore, key challenges ahead which remain to be tackled are also described, many of which have come into clear focus with the current drive towards smarter distribution networks.
For the purpose of improving the voltage profile and power losses reduction, this paper proposes ... more For the purpose of improving the voltage profile and power losses reduction, this paper proposes allocation and sizing of Distributed Generation (DG) in radial distribution system (69 IEEE bus test system.). A simple and effective approach for power loss reduction (PLR) value is employed for the allocation while the sizing was by using the results from the allocation as local optimum in a modified PSO called Ranked Evolutionary particle swarm optimization (REPSO) in order to obtain the global optimum. Load simulations in power flow yielded improvement not only in power loss reduction but also in voltage profile. The proposed algorithm was found to be faster and gives more accurate results than the EP and PSO algorithms. Keywords: Distributed Generation, Evolutionary programming,, Particle Swarm Optimization, Allocation and sizing, Power loss reduction.
International Transactions on Electrical Energy Systems, 2013
This paper presents detail assessment of the impact of renewable energy type distributed generati... more This paper presents detail assessment of the impact of renewable energy type distributed generation operation modes on the voltage stability indices. Most of renewable distributed energy sources are capable of operating in two modes, which are constant voltage and constant power modes. Different simulation results were obtained for voltage stability index (VSI), which serves as indicator of stability. Furthermore, this study has also considered charging station (CS) as a load, that is, gradually increased at the selected bus until the system attains instability state. The persistence of the instability can lead to voltage collapse, and VSI value can give an indication of the collapse as well. In this paper, the concept of active power voltage stability index (P-VSI) is introduced with the aim of predicting the voltage collapse as a result of incremental CS loading in the network. Based on the analysis conducted in radial networks with multiple distributed generation units, the P-VSI gave better indication for the voltage collapse much more than reactive power voltage stability index. The analysis was conducted on 33 bus distribution system.
For the purpose of improving the voltage profile and power losses reduction, this paper proposes ... more For the purpose of improving the voltage profile and power losses reduction, this paper proposes allocation and sizing of Distributed Generation (DG) in radial distribution system (69 IEEE bus test system.). A simp le and effective approach for power loss reduction (PLR) value is employed for the allocation wh ile the sizing was by using the results fro m the allocation as local optimu m in a mod ified PSO called Ran ked Evolutionary particle swarm optimization (REPSO) in order to obtain the g lobal optimu m. Load simu lations in power flow yielded improvement not only in power loss reduction but also in voltage profile. The proposed algorithm was found to be faster and gives more accurate results than the EP and PSO algorith ms.
Abstract: The emergence of Distributed Generation (DG) in distribution network has changed the co... more Abstract: The emergence of Distributed Generation (DG) in distribution network has changed the configuration of this century’s power system in terms of power flow. The reason for this is that DG affects the power flow and voltage conditions in the distribution system; contrary to its traditional unidirectional nature in radial configuration. It is worth mentioning that the change in the direction of power flow is not limited to the distribution network, but can as well extend to the transmission or sub-transmission systems, especially when DG penetration is high. This paper gives an overview of DG types and modeling techniques of the DG for power flow analysis during planning and operations. Various DG technologies are highlighted, different models of DGs are presented and some key challenges ahead with current drive towards smart grid networks is also discussed.
Abstract: The increase in Distributed Generation (DG) penetration in distribution network can be ... more Abstract: The increase in Distributed Generation (DG) penetration in distribution network can be used as a means of addressing the increasing load demand without the upgrade of transmission lines. However, this increasing demand despite the supplementary supply from DG sources can cause the system to operate at its maximum capacity or at point of voltage collapse. It therefore, becomes necessary to determine the maximum capacity limit of the system before voltage collapse occurs due to instability. This paper reviews the concept of voltage stability index (VSI) as an indicator of a weak bus that is closed to its maximum allowable limit or the most critical line to voltage collapse in a network. The review also evaluates various voltage stability indices including those originally developed for transmission systems. Subsequently, their adequacies are quantitatively compared and from the comparison, it is observed that the existing voltage stability indices would be inadequate for ass...
Power losses in distribution networks have increasingly resulted in economic loss during power de... more Power losses in distribution networks have increasingly resulted in economic loss during power delivery to consumers. In order to reduce such losses Distributed Generation (DG) connection to distribution systems have been identified as a means of solving such problem if properly placed in the networks. It is therefore, necessary to include power loss minimization as objective during planning and operation of distribution systems. This paper summaries various optimization methods utilized by researchers for power loss reduction with a view of giving an update in the area and at the same time identifying missing gaps such as investigations on varying nature of loads, development of dynamic placement techniques and improvement on heuristic optimization algorithms as further works for the maximization of the benefits associated with DG as well as minimizing its negative impacts on the entire distribution network.
To relieve congestion due to open-access feature in competitive power system framework, utilities... more To relieve congestion due to open-access feature in competitive power system framework, utilities plan flexible alternating current transmission systems (FACTS), ensuring improved utilization and performance of the transmission infrastructure. However, high-investment cost restricts implementation to single type of FACTS' planning in a time. Therefore, successive planning of another FACTS to delay transmission expansion results in multi-type FACTS planning. Consequently, to optimise performance, subsequent planning must coordinate with existing FACTS. The main objective of this study is to implement coordination of multi-type FACTS for available transfer capability (ATC) enhancement. A hybrid real power flow performance index (PI) and particle swarm optimisation (PSO), coordinate thyristor control series compensator (TCSC) in the first planning horizon with static synchronous series compensator (SSSC) and unified power flow controller (UPFC), in the second horizon. The PI–PSO-based multi-type FACTS coordination improves ATC of multilateral power transfers in a standard 9-buses test network. Results show that multi-type FACTS achieved higher ATC; such that enhanced ATC by TCSC–SSSC ranges between 8.06–69.34% while the TCSC–UPFC ranges between 11.85–71.59% for various power transfer transactions. A comparison of the three coordination schemes shows that the scheme with more decision parameters provides superior loadability and transfer capability improvement.
Proceedings of the 2019 2nd International Conference on Electronics and Electrical Engineering Technology - EEET 2019
This paper presents comparison of an improved MPPT controller using particle swarm optimization (... more This paper presents comparison of an improved MPPT controller using particle swarm optimization (PSO) tuned fractional order fuzzy logic controller (FO-FLC) and conventional fuzzy logic controller for photovoltaic applications. The optimization was carried out in two steps: the first step compute optimal values of scaling factors and fractional operator while the second step optimize Controller output membership functions. The optimization design objective is to minimize Root Mean of Squared Error (RMSE) between a measured power and desired maximum power. The optimal fractional operator shortens the tracking time and eliminate oscillations around MPP. The evaluation of the performance of the proposed controller and the simulations were carried out and the results shows that the FO-FLC provides better performance in terms of tracking speed and accuracy at different atmospheric conditions.
International Journal of Science, Technology and Society, 2015
The increase in Distributed Generation (DG) penetration in distribution network can be used as a ... more The increase in Distributed Generation (DG) penetration in distribution network can be used as a means of addressing the increasing load demand without the upgrade of transmission lines. However, this increasing demand despite the supplementary supply from DG sources can cause the system to operate at its maximum capacity or at point of voltage collapse. It therefore, becomes necessary to determine the maximum capacity limit of the system before voltage collapse occurs due to instability. This paper reviews the concept of voltage stability index (VSI) as an indicator of a weak bus that is closed to its maximum allowable limit or the most critical line to voltage collapse in a network. The review also evaluates various voltage stability indices including those originally developed for transmission systems. Subsequently, their adequacies are quantitatively compared and from the comparison, it is observed that the existing voltage stability indices would be inadequate for assessing the most sensitive bus or line on the verge of voltage collapse for modern distribution systems.
Many power system operators and planners are facing serious challenges as DG penetration increase... more Many power system operators and planners are facing serious challenges as DG penetration increases into the distribution networks. The situation is even more critical if the DG is not properly sited as such can lead to an increased power losses and instability of the network. Most objectives have centered on minimization of only real power loss for the system. In this paper optimal sizing of DG considers not only the losses but also voltage stability index value (VSI) so that voltage stability of the network is improved as well. The study also takes into account all the necessary constraints. The objective functions are handled as single multi-objective function, and was subsequently optimized using the proposed Particle swarm optimization (PSO) algorithm. The effectiveness of the algorithm was tested on IEEE 33-Bus test system and result obtained shows that the proposed method gives better DGs outputs and use of VSI values in the optimization has greatly improved the minimum VSI values of the network when compared to situation without it and the power losses did not increase appreciably. The study has also indicated that optimal DG placement has greatly improved voltage profile and voltage stability of the network as well.
International Journal of Science, Technology and Society, 2015
The emergence of Distributed Generation (DG) in distribution network has changed the configuratio... more The emergence of Distributed Generation (DG) in distribution network has changed the configuration of this century's power system in terms of power flow. The reason for this is that DG affects the power flow and voltage conditions in the distribution system; contrary to its traditional unidirectional nature in radial configuration. It is worth mentioning that the change in the direction of power flow is not limited to the distribution network, but can as well extend to the transmission or sub-transmission systems, especially when DG penetration is high. This paper gives an overview of DG types and modeling techniques of the DG for power flow analysis during planning and operations. Various DG technologies are highlighted, different models of DGs are presented and some key challenges ahead with current drive towards smart grid networks is also discussed.
It is difficult to estimate how much distributed generation (DG) capacity will be connected to di... more It is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years, however, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning and control strategies. The work of this Task Force is focused on the numerous strategies and methods that have been developed in recent years to address DG integration and planning. This paper contains a critical review of the work in this field. Although there have been numerous publications in this area, widespread implementation of the methods has not taken place. The barriers to implementation of the advanced techniques are outlined, highlighting why network operators have been slow to pick up on the research to date. Furthermore, key challenges ahead which remain to be tackled are also described, many of which have come into clear focus with the current drive towards smarter distribution networks.
For the purpose of improving the voltage profile and power losses reduction, this paper proposes ... more For the purpose of improving the voltage profile and power losses reduction, this paper proposes allocation and sizing of Distributed Generation (DG) in radial distribution system (69 IEEE bus test system.). A simple and effective approach for power loss reduction (PLR) value is employed for the allocation while the sizing was by using the results from the allocation as local optimum in a modified PSO called Ranked Evolutionary particle swarm optimization (REPSO) in order to obtain the global optimum. Load simulations in power flow yielded improvement not only in power loss reduction but also in voltage profile. The proposed algorithm was found to be faster and gives more accurate results than the EP and PSO algorithms. Keywords: Distributed Generation, Evolutionary programming,, Particle Swarm Optimization, Allocation and sizing, Power loss reduction.
International Transactions on Electrical Energy Systems, 2013
This paper presents detail assessment of the impact of renewable energy type distributed generati... more This paper presents detail assessment of the impact of renewable energy type distributed generation operation modes on the voltage stability indices. Most of renewable distributed energy sources are capable of operating in two modes, which are constant voltage and constant power modes. Different simulation results were obtained for voltage stability index (VSI), which serves as indicator of stability. Furthermore, this study has also considered charging station (CS) as a load, that is, gradually increased at the selected bus until the system attains instability state. The persistence of the instability can lead to voltage collapse, and VSI value can give an indication of the collapse as well. In this paper, the concept of active power voltage stability index (P-VSI) is introduced with the aim of predicting the voltage collapse as a result of incremental CS loading in the network. Based on the analysis conducted in radial networks with multiple distributed generation units, the P-VSI gave better indication for the voltage collapse much more than reactive power voltage stability index. The analysis was conducted on 33 bus distribution system.
For the purpose of improving the voltage profile and power losses reduction, this paper proposes ... more For the purpose of improving the voltage profile and power losses reduction, this paper proposes allocation and sizing of Distributed Generation (DG) in radial distribution system (69 IEEE bus test system.). A simp le and effective approach for power loss reduction (PLR) value is employed for the allocation wh ile the sizing was by using the results fro m the allocation as local optimu m in a mod ified PSO called Ran ked Evolutionary particle swarm optimization (REPSO) in order to obtain the g lobal optimu m. Load simu lations in power flow yielded improvement not only in power loss reduction but also in voltage profile. The proposed algorithm was found to be faster and gives more accurate results than the EP and PSO algorith ms.
Abstract: The emergence of Distributed Generation (DG) in distribution network has changed the co... more Abstract: The emergence of Distributed Generation (DG) in distribution network has changed the configuration of this century’s power system in terms of power flow. The reason for this is that DG affects the power flow and voltage conditions in the distribution system; contrary to its traditional unidirectional nature in radial configuration. It is worth mentioning that the change in the direction of power flow is not limited to the distribution network, but can as well extend to the transmission or sub-transmission systems, especially when DG penetration is high. This paper gives an overview of DG types and modeling techniques of the DG for power flow analysis during planning and operations. Various DG technologies are highlighted, different models of DGs are presented and some key challenges ahead with current drive towards smart grid networks is also discussed.
Abstract: The increase in Distributed Generation (DG) penetration in distribution network can be ... more Abstract: The increase in Distributed Generation (DG) penetration in distribution network can be used as a means of addressing the increasing load demand without the upgrade of transmission lines. However, this increasing demand despite the supplementary supply from DG sources can cause the system to operate at its maximum capacity or at point of voltage collapse. It therefore, becomes necessary to determine the maximum capacity limit of the system before voltage collapse occurs due to instability. This paper reviews the concept of voltage stability index (VSI) as an indicator of a weak bus that is closed to its maximum allowable limit or the most critical line to voltage collapse in a network. The review also evaluates various voltage stability indices including those originally developed for transmission systems. Subsequently, their adequacies are quantitatively compared and from the comparison, it is observed that the existing voltage stability indices would be inadequate for ass...
Power losses in distribution networks have increasingly resulted in economic loss during power de... more Power losses in distribution networks have increasingly resulted in economic loss during power delivery to consumers. In order to reduce such losses Distributed Generation (DG) connection to distribution systems have been identified as a means of solving such problem if properly placed in the networks. It is therefore, necessary to include power loss minimization as objective during planning and operation of distribution systems. This paper summaries various optimization methods utilized by researchers for power loss reduction with a view of giving an update in the area and at the same time identifying missing gaps such as investigations on varying nature of loads, development of dynamic placement techniques and improvement on heuristic optimization algorithms as further works for the maximization of the benefits associated with DG as well as minimizing its negative impacts on the entire distribution network.
To relieve congestion due to open-access feature in competitive power system framework, utilities... more To relieve congestion due to open-access feature in competitive power system framework, utilities plan flexible alternating current transmission systems (FACTS), ensuring improved utilization and performance of the transmission infrastructure. However, high-investment cost restricts implementation to single type of FACTS' planning in a time. Therefore, successive planning of another FACTS to delay transmission expansion results in multi-type FACTS planning. Consequently, to optimise performance, subsequent planning must coordinate with existing FACTS. The main objective of this study is to implement coordination of multi-type FACTS for available transfer capability (ATC) enhancement. A hybrid real power flow performance index (PI) and particle swarm optimisation (PSO), coordinate thyristor control series compensator (TCSC) in the first planning horizon with static synchronous series compensator (SSSC) and unified power flow controller (UPFC), in the second horizon. The PI–PSO-based multi-type FACTS coordination improves ATC of multilateral power transfers in a standard 9-buses test network. Results show that multi-type FACTS achieved higher ATC; such that enhanced ATC by TCSC–SSSC ranges between 8.06–69.34% while the TCSC–UPFC ranges between 11.85–71.59% for various power transfer transactions. A comparison of the three coordination schemes shows that the scheme with more decision parameters provides superior loadability and transfer capability improvement.
Proceedings of the 2019 2nd International Conference on Electronics and Electrical Engineering Technology - EEET 2019
This paper presents comparison of an improved MPPT controller using particle swarm optimization (... more This paper presents comparison of an improved MPPT controller using particle swarm optimization (PSO) tuned fractional order fuzzy logic controller (FO-FLC) and conventional fuzzy logic controller for photovoltaic applications. The optimization was carried out in two steps: the first step compute optimal values of scaling factors and fractional operator while the second step optimize Controller output membership functions. The optimization design objective is to minimize Root Mean of Squared Error (RMSE) between a measured power and desired maximum power. The optimal fractional operator shortens the tracking time and eliminate oscillations around MPP. The evaluation of the performance of the proposed controller and the simulations were carried out and the results shows that the FO-FLC provides better performance in terms of tracking speed and accuracy at different atmospheric conditions.
International Journal of Science, Technology and Society, 2015
The increase in Distributed Generation (DG) penetration in distribution network can be used as a ... more The increase in Distributed Generation (DG) penetration in distribution network can be used as a means of addressing the increasing load demand without the upgrade of transmission lines. However, this increasing demand despite the supplementary supply from DG sources can cause the system to operate at its maximum capacity or at point of voltage collapse. It therefore, becomes necessary to determine the maximum capacity limit of the system before voltage collapse occurs due to instability. This paper reviews the concept of voltage stability index (VSI) as an indicator of a weak bus that is closed to its maximum allowable limit or the most critical line to voltage collapse in a network. The review also evaluates various voltage stability indices including those originally developed for transmission systems. Subsequently, their adequacies are quantitatively compared and from the comparison, it is observed that the existing voltage stability indices would be inadequate for assessing the most sensitive bus or line on the verge of voltage collapse for modern distribution systems.
Many power system operators and planners are facing serious challenges as DG penetration increase... more Many power system operators and planners are facing serious challenges as DG penetration increases into the distribution networks. The situation is even more critical if the DG is not properly sited as such can lead to an increased power losses and instability of the network. Most objectives have centered on minimization of only real power loss for the system. In this paper optimal sizing of DG considers not only the losses but also voltage stability index value (VSI) so that voltage stability of the network is improved as well. The study also takes into account all the necessary constraints. The objective functions are handled as single multi-objective function, and was subsequently optimized using the proposed Particle swarm optimization (PSO) algorithm. The effectiveness of the algorithm was tested on IEEE 33-Bus test system and result obtained shows that the proposed method gives better DGs outputs and use of VSI values in the optimization has greatly improved the minimum VSI values of the network when compared to situation without it and the power losses did not increase appreciably. The study has also indicated that optimal DG placement has greatly improved voltage profile and voltage stability of the network as well.
International Journal of Science, Technology and Society, 2015
The emergence of Distributed Generation (DG) in distribution network has changed the configuratio... more The emergence of Distributed Generation (DG) in distribution network has changed the configuration of this century's power system in terms of power flow. The reason for this is that DG affects the power flow and voltage conditions in the distribution system; contrary to its traditional unidirectional nature in radial configuration. It is worth mentioning that the change in the direction of power flow is not limited to the distribution network, but can as well extend to the transmission or sub-transmission systems, especially when DG penetration is high. This paper gives an overview of DG types and modeling techniques of the DG for power flow analysis during planning and operations. Various DG technologies are highlighted, different models of DGs are presented and some key challenges ahead with current drive towards smart grid networks is also discussed.
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