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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.

The phenomenon this paper looks at is power swings, voltage collapse, series compensation and the effect of shunt active VAR compensation. Power swing blocking although a well established technique in its own right; is hampered by traditional detection methods which can be compromised when the system topology changes. Voltage collapse (insufficient VARS) and its effect on distance protection is not a subject which has had wide spread discussion. Fast and slow VAR compensation devices like SVC's and STATCOM bring in new challenges to this traditional art. Series compensation is also being considered on relatively short lines in order to export more power through existing corridors and has implications on distance reach as well as directionality. (5 pages)

Abstract The analysis and optimization of flat plate fins of constant thickness and straight base has been conducted for different fin’s shapes. Performance of the fins is quantified through effectiveness and expressed as a function of fin’s shape, width, and area. A linear piecewise function with varying number of evenly spaced sections is used to generate shapes with different number of degrees of freedom, which are classified as constrained- or unconstrained-base depending on the width of the fin at the constant temperature base location. For one- and two-degrees of freedom shapes, a variety of rectangular, triangular, trapezoidal, and rhomboidal geometries are considered and optimized. For more than two-degrees of freedom, more complex resulting shapes are also considered. By adjusting the value of the corresponding shape parameters, the best possible distributions of available area to maximize heat transfer are obtained, which produce significant improvements favored by smaller width and larger area. Unconstrained-base performs better than constrained-base configurations as they allow the distribution of a larger area close to the high-temperature base. Optimal shape of unconstrained-base fins is in general convergent with non-zero wide tip, while, for constrained-base fins, it is divergent in the first linear section from the base and convergent in the remaining ones. For increasing number of degrees of freedom the optimized shapes tend to resemble natural structures while effectiveness increases asymptotically to a limit for constant width and area. Besides determining the optimal configurations, consideration has been made about the optimal regions where a variety of shapes produce virtually the same effectiveness of the absolute maximum, which can be used to design fins with almost maximum performance but having simpler shapes or being functional under possible space restrictions. The dimensionless model and the systematic analysis proposed in this work are not only appropriate to study a wide range of flat plate fins but also can be implemented to analyze and perform optimization over other type of fins and fins configurations.

The latest information from Hiroshima and Nagasaki on radiation-induced cancer in man includes new DS86 dose assignments and extension of the Life-Span Study Sample cohort through 1985. The implications of these new doses and updated data for the assessment of cancer risk at low to moderate doses have been evaluated. Results from the fitting of three dose-response models (linear, quadratic, linear-quadratic) to the data at doses less than 1.5 Gy are reported. Based on statistical analyses of the authors' results, comments are made concerning the possible shapes of dose-response curves for human cancer.

While a firm knows the carbon price with certainty under a tax, it must form an expectation about future allowance prices to identify its cost-effective abatement investment under a capand-trade program. We illustrate graphically how errors in forming this expectation increase the costs of irreversible pollution abatement investment under cap-and-trade relative to a tax. We describe empirical “cost-effectiveness anomalies” in allowance markets that may be attributed to cap-and-trade's inherent uncertainty. We model investment under simulated US carbon tax and cap-and-trade policies and find that allowance price uncertainty can increase resource costs 20 percent for a given quantity of emission abatement.

Ultrarich filtration combustion of ethane is studied in a porous medium composed of alumina spheres with the aim to achieve optimized conversion to hydrogen and syngas. Temperature, velocities, and...

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.