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One of the main uncertainties in long‐term distribution network planning is load forecasting error. This paper presents a probabilistic multistage expansion planning method to consider the load forecasting error as well as pseudo dynamic behavior of network parameters and geographical constraints. The optimal routes of MV feeders as backbone of distribution networks are obtained for both mid and long‐term case with deterministic and probabilistic modeling. The Imperialist Competitive Algorithm (ICA) is adapted for the optimal expansion planning of MV distribution network. To check and maintain the radial configuration of the MV distribution network during ICA random operators, a novel algorithm is employed. Comparative tabular and graphical results are given for deterministic and probabilistic planning. In probabilistic case the results is also represented by histogram of statistics data, mean and standard deviation of input and output variables using Monte Carlo Simulation (MCS). Based on the results it is possible to design the MV network at the presence of uncertainties more robust and flexible with respect to deterministic planning without reasonable increase in total cost. The efficiency and capability of the method is tested on a relatively large‐scale distribution network.

One of the main uncertainties in long‐term distribution network planning is load forecasting error. This paper presents a probabilistic multistage expansion planning method to consider the load forecasting error as well as pseudo dynamic behavior of network parameters and geographical constraints. The optimal routes of MV feeders as backbone of distribution networks are obtained for both mid and long‐term case with deterministic and probabilistic modeling. The Imperialist Competitive Algorithm (ICA) is adapted for the optimal expansion planning of MV distribution network. To check and maintain the radial configuration of the MV distribution network during ICA random operators, a novel algorithm is employed. Comparative tabular and graphical results are given for deterministic and probabilistic planning. In probabilistic case the results is also represented by histogram of statistics data, mean and standard deviation of input and output variables using Monte Carlo Simulation (MCS). Based on the results it is possible to design the MV network at the presence of uncertainties more robust and flexible with respect to deterministic planning without reasonable increase in total cost. The efficiency and capability of the method is tested on a relatively large‐scale distribution network.

AbstractService unavailability of transmission lines, due to the direct and indirect lightning strikes, is evaluated as a challenging issue within electric companies. The lightning event can produce dangerous overvoltage, equipment failures, and power supply interruptions. Here, externally gapped line arresters (EGLAs) performances installed on a 63 kV transmission line are modelled using EMTP‐ATP to investigate their capability to withstand current and energy discharged by lightning strokes during back flashover phenomena. Frequency behaviour of the grounding system impedance, first and subsequent lightning current parameters effects on insulators back flashover and lightning flashover failure rate have been considered by Monte‐Carlo method. Then, extensive analysis has been carried out to study the absorbed energy of the EGLA and its expected life. The results show the dependency of failure rate and the EGLA expected life on the soil resistivity and lightning strike parameters. The selected EGLA must be provided sufficient lightning protection to the transmission line based on its absorbed energy capability, the soil and lightning parameters and be complied with the discharge energy capability requirement specified by the utility company.

AbstractService unavailability of transmission lines, due to the direct and indirect lightning strikes, is evaluated as a challenging issue within electric companies. The lightning event can produce dangerous overvoltage, equipment failures, and power supply interruptions. Here, externally gapped line arresters (EGLAs) performances installed on a 63 kV transmission line are modelled using EMTP‐ATP to investigate their capability to withstand current and energy discharged by lightning strokes during back flashover phenomena. Frequency behaviour of the grounding system impedance, first and subsequent lightning current parameters effects on insulators back flashover and lightning flashover failure rate have been considered by Monte‐Carlo method. Then, extensive analysis has been carried out to study the absorbed energy of the EGLA and its expected life. The results show the dependency of failure rate and the EGLA expected life on the soil resistivity and lightning strike parameters. The selected EGLA must be provided sufficient lightning protection to the transmission line based on its absorbed energy capability, the soil and lightning parameters and be complied with the discharge energy capability requirement specified by the utility company.

Due to the single-phase loads and their stochastic behavior, the current in the distribution feeders is not balanced. In addition, the single-phase loads are located in different positions along the LV feeders. So the amount of the unbalanced load and its location affect the feeder losses. An unbalanced load causes the feeder losses and the voltage drop. Because of time-varying behavior of the single-phase loads, phase balancing is a dynamic and combinatorial problem. In this research, a heuristic and dynamic solution for the phase balancing of the LV feeders is proposed. In this method, it is supposed that the loads’ tie could be connected to all phases through a three-phase switch. The aim of the proposed method is to make the feeder conditions as balanced as possible. The amount and the location of single-phase loads are considered in the proposed phase balancing method. Since the proposed method needs no communication interface or no remote controller, it is inexpensive, simple, practical, and robust. Applying this method provides a distributed and dynamic phase balancing control. In addition, the feasibility of reducing the used switches is investigated. The ability of the proposed method in the phase balancing of the LV feeders is approved by carrying out some simulations.

Due to the single-phase loads and their stochastic behavior, the current in the distribution feeders is not balanced. In addition, the single-phase loads are located in different positions along the LV feeders. So the amount of the unbalanced load and its location affect the feeder losses. An unbalanced load causes the feeder losses and the voltage drop. Because of time-varying behavior of the single-phase loads, phase balancing is a dynamic and combinatorial problem. In this research, a heuristic and dynamic solution for the phase balancing of the LV feeders is proposed. In this method, it is supposed that the loads’ tie could be connected to all phases through a three-phase switch. The aim of the proposed method is to make the feeder conditions as balanced as possible. The amount and the location of single-phase loads are considered in the proposed phase balancing method. Since the proposed method needs no communication interface or no remote controller, it is inexpensive, simple, practical, and robust. Applying this method provides a distributed and dynamic phase balancing control. In addition, the feasibility of reducing the used switches is investigated. The ability of the proposed method in the phase balancing of the LV feeders is approved by carrying out some simulations.

Abstract In this paper, a general mathematical model for the dynamic simulation of a single-effect LiBr/water absorption chiller is presented. The model is based on mass and energy balances applied to the internal components of the machine, and it accounts for the non-steady behaviour due to thermal and mass storage in the components. The validation of the mathematical model is performed through experimental data collected on a commercial small-capacity water-cooled unit. Due to the peculiar technology adopted in the real chiller, a special effort was made to identify the appropriate values of the main physical parameters. The validation of the model is based on the values of the water temperature at the outlet of the machine, as no measurement inside the machine was possible; anyway, a consistency analysis applied to the internal parameters is also presented. The agreement between experimental and simulated results is very good, both on a daily and on a seasonal basis.

Abstract In this paper, a general mathematical model for the dynamic simulation of a single-effect LiBr/water absorption chiller is presented. The model is based on mass and energy balances applied to the internal components of the machine, and it accounts for the non-steady behaviour due to thermal and mass storage in the components. The validation of the mathematical model is performed through experimental data collected on a commercial small-capacity water-cooled unit. Due to the peculiar technology adopted in the real chiller, a special effort was made to identify the appropriate values of the main physical parameters. The validation of the model is based on the values of the water temperature at the outlet of the machine, as no measurement inside the machine was possible; anyway, a consistency analysis applied to the internal parameters is also presented. The agreement between experimental and simulated results is very good, both on a daily and on a seasonal basis.