Abstract
Unbalanced feeders produce problems and risky situations since they can trip protection devices, reduce the efficiency and damage some appliances. Therefore achieve the balance of the networks will mean an improvement of the electric service and reduction expenses. The proposed program is a tool for balancing the electric networks; swapping loads among phases of the main lines, to assure that the loads average among the phases of the main lines not do not in large magnitudes. It is assumed that all loads have the same power factor and voltage drops are not considered. As a fundamental contribution of this work, an additional restriction is added to the mathematical model that avoids the introduction of additional phases.

Abstract
This paper valuates generation assets within deregulated electricity markets. A new framework for modeling electricity markets with a Markov chain model is proposed. The Markov chain model captures the fundamental economic forces underlying the electricity markets such as demand on electricity and supplied online generation capacity. Based on this new model, a real option analysis is adopted to valuate generation assets. The Markov chain model is combined with a binomial tree to approximate the stochastic movement of prices on both electric energy and ancillary services, which are driven by the market forces. A detailed example is presented. This method is shown to provide optimal operation policies and market values of generation assets. This method also provides means to analyze the impacts of demand growth patterns, competition strategies of competitors, and other key economic forces.

Abstract
Recently, the new concept of microgrid (mu G) has been emerging on distribution networks as a way to ease the integration of micro generation in LV networks and increase reliability. A mu G is an association of a low voltage distribution network, small modular generation systems (micro-generators), loads and storage devices having some local coordinated functions. This entity can operate in two different modes: interconnected or emergency. In the first mode, the microgrid is connected with the distribution network, importing or exporting electricity and/or ancillary services. When in emergency mode, the microgrid operates isolated from the distribution network and uses local resources, changing from power control to frequency control and, if necessary, shedding load. A micro grid will only be established if its promoters achieve sufficient advantages that justify the incurred costs, namely the investment, operation and maintenance costs. The main purpose of this paper is to identify all the relevant costs and benefits and build a decision model for the situation, taking into account the regulatory framework, which is essential for the definition of some of the benefits. The paper also shows how to include in the evaluation the risk associated to the uncertainties in data and parameters. An illustrative example is included that shows a possible situation of equilibrium between global costs and benefits.

Abstract
When customers demand for very short lead-times and for a strict respect of the delivery schedules, it becomes difficult to avoid the existence of relatively large work-in-process buffers. As the buffers will also increase dramatically the production costs, their design (location and capacity) should be carefully analyzed and optimized, a task that becomes rather complex for large production systems. This paper firstly introduces a series of fundamental concepts related to the reliability of production systems. Then, the rationale of an analysis method oriented to this class of systems will be presented, together with its two main components, the modelling framework and the evaluation algorithm. The method allows analysing several issues of the design and operation of the production systems, namely the redundancy of equipment, the layout of the cells and the maintenance policies. To illustrate its practical usefulness and enlighten the kind of results that the method can provide, a numerical example concerning the design of work-in-process buffers of a just-in-time manufacturing system will be presented in the final part of the paper.

Abstract
The current fixed tariff remuneration for wind energy is not compatible with the deregulation of the electric power industry. The time-varying and location-dependent value of renewable energy is not acknowledged. The newly announced switchable tariff for wind energy in the Spanish electricity market provides a promising solution to compensating renewable energy within the deregulated electric power industry. The new switchable tariff provides wind generators more flexibility in operating wind generation assets. Such flexibilities provide option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement. This paper models and valuates the flexibility on switching tariff as real compound options for wind generators. Numerical examples valuate wind generation assets under fixed tariff, spot market price taking, and yearly and monthly switchable tariffs. The optimal switching strategies are identified. The impacts of the switchable tariff on sitting criteria and values of wind generation assets are investigated. An improvement on the yearly switchable tariff is suggested to further reduce the operation risk of wind generators and fully explore the efficiency provided by competitive electricity markets.

Abstract
Reliability models rarely incorporate the uncertainty that is present in most of the reliability parameters, which is an important limitation for the managers of production system. This paper presents a fuzzy-probabilistic methodology that was developed to analyse production systems. The methodology employs probabilistic theory to represent the stochastic behaviour of the failure and repair processes and fuzzy sets to represent uncertainty in the parameters. This approach is based on a fuzzy reliability analysis from which is possible to obtain the fuzzy downtime function of a system in a given period of analysis. This function is a crucial element to obtain two performance measures: a financial measure (the fuzzy cost concerning failures of a production system) and a quality of service measure (the fuzzy frequency of failure on deliveries), as it will be illustrated in the final part of the paper through a practical example.