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This paper presents an analytical technique to evaluate the reliability of customers in a microgrid including distributed generations (DGs). Operators of the microgrid are responsible for a reliable energy supply to their customers. Due to the strategy of the priority on their customers, the restoration process of DGs should be reordered when system outage happens. The previous study has proposed the analytical technique to evaluate the reliability of customers in the distribution system that one operator owns all DGs. The proposed method includes photovoltaic (PV) systems and fuses, and the impact factor is modified to obtain the interruption cost. Also, equations are generalized to consider more than one component in a section. Case studies in RBTS Bus 4 verify that the accuracy of the proposed technique is comparable to that of MCS, and the configuration of system divided into several microgrids changes the reliability of customers in the microgrids. Index Terms--Connection matrix, distributed generation, impact factor, microgrid, reliability of customers.

This paper presents an analytical technique for evaluating the reliability of a distribution system, including distributed generation. Unlike the large-scale generation of the transmission system, distributed generation (DG) creates difficulties in evaluating reliability indices due to the complexity of the operation status. Explicit expressioas for analyzing the reliability of distributed generation are proposed in this paper. The technique proposed includes the characteristics of DG, such as operation mode to mix peaking and standby modes and the failure of starting and DG itself. Index Terms--Analytical technique, connection matrix, distributed generation, distribution system, impact factor, load duration curve, reliability.

This paper represents an exact modeling for autotransformer (AT)-fed ac high-speed railroad (HSR) using constant current mode. AC HSR has rapidly changing single-phase load, and at a feeding substation, three-phase electric power is transformed to the paired directional single-phase electric power. As the train moves along a section of line between two adjacent ATs, analysis of the catenary voltage in AT-fed ac HSR system is a quite complicated work. Therefore, in order to solve this complicated system, this paper proposes a novel and efficient method with generalized equations for the catenary voltage of AT-fed ac HSR. The voltage profile through the entire railroad system can be solved regardless of the number and position of trains, feeding distance from substation, and normal or extension mode. In the case studies, the results of the proposed equation for the catenary voltage profile are compared with those of the simulation using PSCAD/EMTDC. Index Terms--AC railroad system, autotransformer (AT), catenary voltage analysis, high-speed railroad (HSR).

This paper presents a method to determine optimal operating strategy for distributed generation (DG) incorporating reliability worth evaluation of a distribution system. The use of DG for peak shaving could reduce the overall system operating cost and its use as standby power could reduce the customer interruption cost. If the DG operating cost is less than the utility power cost at peak time, DG should be employed to reduce the overall system operating cost. However, when customer interruption cost is also an important concern, standby power strategy for DG may be better than peak shaving. The reliability worth and the power cost evaluations are needed to determine whether DG should be operated for peak shaving or as standby power. The hourly reliability worth is incorporated in the strategy proposed in this paper to determine the optimal operating decision for the DG. Using the approach proposed in this paper, the distribution companies could determine the optimal operating strategy for their DG. Index Terms--Distributed generation (DG), distribution system, reliability worth, sequential simulation.

This paper deals with the effect of an adjacent viscous fluid on the torsional vibration of a circular rod excited by a transducer at one end. The interaction between the torsional vibration of the rod and the fluid has been studied theoretically and expressed in terms of mechanical impedance. The theoretically-obtained result that the mechanical impedance is proportional to the square root of the viscosity times mass density of the fluid has been confirmed by the experiment measuring electric impedance. This paper demonstrates that a torsionally-vibrating rod can be used as a sensor for measuring the viscosity of a fluid. [DOI: 10.1115/1.1525004]

This paper presents an efficient algorithm for loss minimization by using an automatic switching operation in large-scale distribution systems. Simulated annealing is particularly well suited for a large combinatorial optimization problem since it can avoid local minima by accepting improvements in cost. However, it often requires a meaningful cooling schedule and a special strategy, which makes use of the property of distribution systems in finding the optimal solution. In this paper, we augment the cost function with the operation condition of distribution systems, improve the perturbation mechanism with system topology, and use the polynomial-time cooling schedule, which is based on the statistical calculation during the search. The validity and effectiveness of the proposed methodology is demonstrated in the Korea Electric Power Corporation's distribution system. Index Terms--Combinatorial optimization problem, cooling schedule, distribution system, loss minimization, network reconfiguration, perturbation mechanism, power flow, simulated annealing.

This paper presents a conceptual possibilistic approach using fuzzy set theory to manage the uncertainties in the reliability input data of real power systems. In this paper, an algorithm is introduced to calculate the possibilistic reliability indices according to the degree of uncertainty in the given data. The probability distribution function can be transformed into an appropriate possibilistic representation using the probability-possibility consistency principle (PPCP) algorithm. In this algorithm, the transformation is performed by making a compromise between the transformation consistency and the human experience. Fuzzy classification theory is applied to reduce the number of load data points. The fuzzy classification method determines the closeness 1 of load data points by assigning them to various clusters and then J determining the distance between the clusters. The IEEE-RTS with 32-generating units is used to demonstrate the capability of the proposed algorithm. Index Terms--Loss-of-load expectation, forced outage rate, probability-possibility consistency principle, fuzzy clustering.

A load model is needed for the power system analysis including load flow and stability studies. The load model representation needs the load composition rate indicating the portion of several typical load groups. This paper proposes a refined load composition rate estimation algorithm with input data which are relative coefficients, limit values, and the energy portion of load groups. An expert system is constructed with the consideration of the uncertainty of input data. The load composition rates in several customers in the power system are obtained and the results of case studies show that a reasonable load composition rate is achieved. Keywords: Load model, Estimation of load composition rate, Expert system

Determination of the effective elastic constants of nitride single-crystal superlattice films involves the use of line-focus acoustic microscopy (LFAM). The calculation estimates the elastic constants of the constituent layers of the film. A comparison with the surface acoustic wave (SAW) velocities establishes the accuracy of LFAM results. The method is suitable for films with flat and sharp inter-layer interfaces and for films with rough interfaces with interdiffusion.

The mass density and elastic constants of isotropic and anisotropic thin films and anisotropic solids are determined by using the known value of mass density to compute the wave velocities. The wave velocities provide information on elastic constants and mass density. The surface acoustic wave velocity values of isotropic solids should be combined with the longitudinal wave velocity to obtain mass density and elastic constants.