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This paper proposes the planning method for capacitor installation in a distribution system to reduce the installation costs and minimize the loss of electrical energy. The expected lifetime of devices with moving parts depends on the total number of operations, which affects the replacement period and replacement decisions for aging equipment under a limited budget. In this paper, the expected device lifetimes are included in the formulation, and the optimal operation status of the devices is determined using a genetic algorithm. The optimal numbers and locations for capacitor installation are determined based on the optimal operation status. Simulation results in a 69-bus distribution system show that the proposed technique performs better than conventional methods. Index Terms--Distribution system, genetic algorithm, operation cost, planning, shunt capacitor, under-load tap changer.

This paper proposes a coordinated control method for an under-load tap changer (ULTC) with switching capacitors in distribution systems to reduce the operation numbers of both devices. The proposed method consists of two stages. In the first stage, the dispatch schedule of capacitors is determined using a genetic algorithm with forecasted loads to reduce the power loss and to improve the voltage profile during a day. In the second stage, each capacitor operates according to this dispatch schedule and the ULTC is controlled in real time with the modified reference voltages considering the dispatch schedule of the capacitors. Simulation results show that the proposed method performs better than a conventional control method. Index Terms--Capacitor, coordinated voltage control, genetic algorithm, modified reference voltage, under-load tap changer.

The protective devices and switches play an important role in the reliability of electrical distribution systems by minimizing the impact of interruption. In this paper, a method for identifying the type and location for protection devices and switches on the prerouted distribution system using value-based optimization is proposed. The proposed method is based on the contingency analysis of various components, e.g., the faults of line sections, switches, protective devices, and the restoration through switching actions such as upstream restoration and downstream restoration. The formulation of the optimization problem in this paper is appropriate for linear integer programming, where each nonlinear term can be translated by only two additional linear constraints. The detailed design of the protection devices and the switches are determined by minimizing the total cost of reliability that comprises apparatus investment, maintenance, and interruption cost. The efficiency and validity of the proposed method are demonstrated in case studies. Index Terms--Integer programming, power distribution, power distribution planning, power distribution protection, power distribution reliability.

In this paper, a method for the fault section estimation that considers the network topology under the influence of a circuit breaker tripped by the previous fault is proposed. The proposed method uses a three-dimensional (3-D) matrix to represent the network topology and the protection systems. The proposed network matrix describes the sections that are protected by particular protective devices that can be changed according to the network topology. To deal with the uncertainties imposed on the protection systems, the fuzzy set theory was applied to the network matrix in order to examine the relationships between the operated protective devices and the fault section candidates. A systematic method for the fuzzy membership function for each relation is proposed. In the proposed method, the operated time sequences of the protective devices were employed because either the network matrix or the network topology varied whenever the operations of the circuit breakers occur. The efficiency and adaptivity of the proposed method were demonstrated in experimental studies on real power systems in the Korean electric power system, particularly in case of complicated multiple faults. Index Terms--Fault diagnosis, fuzzy set, power system.

In this paper, a new approach to maintenance scheduling of generating units (MSU) in competitive electricity markets is presented. The main contribution of this study can be focused on modeling a game-theoretic framework for the MSU problem to analyze strategic behaviors of generating companies (Gencos). The MSU problem is formulated as a dynamic noncooperative game with complete information. The player corresponds to the profit maximizing individual Genco, and the payoff of each player is defined as the profit from the energy auction market. The optimal strategy profile is defined by the Nash equilibrium of the game. Numerical results for two-Genco systems are used to demonstrate the basic ideas of the proposed scheme, and large-scale IEEE reliability test systems are also considered to show the applicability of the proposed framework. The results obtained indicate that maintenance schedule can be one of the crucial strategic behaviors whereby Genco maximizes their profit in a competitive market environment. Index Terms--Competitive market, dynamic noncooperative game, maintenance scheduling of generating unit, maintenance strategy, Nash equilibrium.

The ab initio second order effective valence shell Hamiltonian which is based on quasidegenerate many-body perturbation theory has been applied to the SiH2+ dication. From the characteristic properties of Hv, all the valence states are determined with a same accuracy. The four low lying quasibound states (X 2Σ+, A 2Π, a 4Π, C 2Σ+) are found for the dication. It is verified that the existence of some quasibound states is due to the interaction of an attractive state from ion-neutral pair asymptote with a same symmetry repulsive state from ion–ion pair asymptote. Since the experimental data are scarce, this work provides all theoretical spectroscopic properties of these quasibound states. Also the repulsive valence states are examined. [ABSTRACT FROM AUTHOR]

Presents a calculation of the potential energy curves of the ground and the low lying excited states for the dissociation of the Rydberg NH[sub 4] radical using ab initio Hartree-Fock and singly excited configuration interaction methods. Finding of an avoided curve crossing between two attractive diabatic states and a repulsive diabatic state.

Polyelectrolyte multilayer films (PEMs) are conventionally prepared by a layer-by-layer (LbL) deposition of alternating polycation and polyanion solutions. We introduce herein a block copolymer (BCP) approach employing a BCP with an H-bond acceptor block and a protected H-donor block as a masked polyampholyte to form new types of PEMs. [ABSTRACT FROM AUTHOR]

Previous studies on the economic evaluation of offshore wind farms (OWFs) have paid limited attention to the cost model. On the contrary, the emphasis in this paper is on eliciting the economic feasibility of OWFs in South Korea by means of the capacity mechanism in a proper revenue context. In the proposed scheme, revenues from the capacity mechanism are duly represented by the product of the capacity credit and the capacity price alike. Three scenarios for neighboring seas near Jeju Island in South Korea are specifically adapted for use of the proposed revenue-centered structure by similar OWFs in real-world situations. And the sensitivity analysis is executed to find some influencing financial parameters such as energy price or corporate tax rate and their correlation with the investigated subsidization strategies. Obviously, the economic values for each independent case will ensure that the economics of OWFs are contingent upon the level of the capacity price. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The increasing penetration of plug-in electric vehicles (PEVs) may cause a low-voltage problem in the distribution network. In particular, the introduction of charging stations where multiple PEVs are simultaneously charged at the same bus can aggravate the low-voltage problem. Unlike a distribution network operator (DNO) who has the overall responsibility for stable and reliable network operation, a charging station operator (CSO) may schedule PEV charging without consideration for the resulting severe voltage drop. Therefore, there is a need for the DNO to impose a coordination measure to induce the CSO to adjust its charging schedule to help mitigate the voltage problem. Although the current time-of-use (TOU) tariff is an indirect coordination measure that can motivate the CSO to shift its charging demand to off-peak time by imposing a high rate at the peak time, it is limited by its rigidity in that the network voltage condition cannot be flexibly reflected in the tariff. Therefore, a flexible penalty contract (FPC) for voltage security to be used as a direct coordination measure is proposed. In addition, the optimal coordinated management is formulated. Using the Pacific Gas and Electric Company (PG&E) 69-bus test distribution network, the effectiveness of the coordination was verified by comparison with the current TOU tariff. [ABSTRACT FROM AUTHOR]

This work describes acylation reactions facilitated by a type of heterocycle-based acyl transfer agent, 2-acyloxypyridazinone. Reactions of 2-acyloxypyridazinone with carboxylic acids yield mixed carbonic anhydride intermediates, which are reactive and could be coupled with a wide range of substrates including acids, amines, alcohols, and thiols. The wide substrate scope, ease of operation (no additive or catalyst), storage and handling stability, and atom-efficiency from recycling the heterocycle carrier make the reported acylating agent attractive for acylation-based coupling reactions. [ABSTRACT FROM AUTHOR]

Consumer electricity consumption can be controlled through electricity prices, which is called demand response. Under demand response, retailers determine their electricity prices, and customers respond accordingly with their electricity consumption levels. In particular, the demands of customers who own electric vehicles (EVs) are elastic with respect to price. The interaction between retailers and customers can be seen as a game because both attempt to maximize their own payoffs. This study models an at-home EV charging scenario as a Stackelberg game and proves that this game reaches an equilibrium point at which the EV charging requirements are satisfied, and retailer profits are maximized when customers use our proposed utility function. The equilibrium of our game can vary according to the weighting factor for the utility function of each customer, resulting in various strategic choices. Our numerical results confirm that the equilibrium of the proposed game lies somewhere between the minimum-generation-cost solution and the result of the equal-charging scheme. [ABSTRACT FROM PUBLISHER]

With the high penetration level of wind power in power systems, wind power generation is necessary to participate in the generation scheduling to balance supply and demand. If a power system operator wants wind power generation to participate in generation scheduling, wind power should be forecasted accurately. Varying weather conditions constantly subject wind power generation to uncertainty and variability, making the determination of generating capacity difficult for system operators. Wind power forecasting should be corrected to reduce errors of generation scheduling. This study proposes a method to correct wind power forecasting by considering wind speed forecast error, which is represented in normal distribution. The biased mean of wind power forecast error is calculated using the analytical approach for wind speed forecast. The proposed method corrects wind power forecast by subtracting the biased mean from the wind power forecast error. [ABSTRACT FROM AUTHOR]