Loss Of Energy Expectation Research Articles

Generating adequacy analysis of Mexico’s national interconnected power system

Purpose Long-term reliability analysis of generation capacity based on the forecasted load demand helps to identify the optimal generation expansion plan of the system. This paper analyzes the generation adequacy of Mexico’s National Interconnected Power System (MNIPS) using loss of load expectation (LOLE) and loss of energy expectation (LOEE) indices. Design/methodology/approach These indices are calculated through an analytical (recursive) method and are then compared with values recommended by the North American Electric Reliability Council (NERC). Weekly indices are computed to analyze the load curtailment options that may occur in some periods. Findings Forecasted values, including load and generation capacity considering maintenance schedules, additions of new generating units and permanently shut down units in accordance with the long-term expanding-system plan have been considered. The load forecast uncertainty is also included. Originality/value This is original work.

An efficient probabilistic-chronological matching modeling for DG planning and reliability assessment in power distribution systems

In recent decades, power distribution systems have encountered a considerable shift toward utilizing renewable resource based distributed generation (DG) systems. This is due to the proven ability of DGs to reduce fossil fuel consumption, which reduces harm done to the environment. In this paper, a new state reduction algorithm is proposed to determine the minimum number of states required to describe or represent the behavior of wind speed and solar irradiance in DG planning problems and reliability analysis. This algorithm could be generalized to incorporate any planning problem where wind or PV power is part of its parameters. Moreover, an adequate time representation that mimics the fluctuation of renewable resource based DGs and chronologically matches the fluctuations in system demand is presented. Three different data clusters are applied (monthly, seasonal and yearly) to investigate the variability of DG power output and electricity demand on both DG planning problems and reliability assessment. These models are evaluated considering DG siting and sizing problems, as well as a supply adequacy-based reliability assessment. The proposed model measures the deviations in annual energy losses (AEL), total DG penetration, loss of load expectation (LOLE), and loss of energy expectation (LOEE).

Fuzzy Numbers Based on Energy Indicators of Reliability Power System

This paper presents the approach of fuzzy numbers for reliability calculation of electrical energy indices and compared to an analytical method. In this paper, the fuzzy numbers which are represented by triangular fuzzy numbers are used to evaluate the load duration curve and the probabilities capacity generators that are in services, in term of the expected energy not supplied (EENS), loss of energy expectation (LOEE) and the energy index of the reliability (EIR). A case study based on the Malaysia distribution network (DISCO-Net) is carried out.The proposed method shows a simple implementation and the results seem to be a good approximation to the analytical approach.

The effect of average cycling current on total energy of lithium-ion batteries for electric vehicles

Predicting the remaining range of a battery reliably, accurately and simply is imperative for effective power management of electrified vehicles and reducing driver anxiety resulting from perceived low driving range. Techniques for predicting the remaining range of an electric vehicle exist; in the best cases they are scaled by factors that account for expected energy losses due to driving style, environmental conditions and the use of on-board energy consuming devices such as air-conditioning. In this work, experimental results that establish the dependence of remaining electrical energy on the vehicle battery immediate cycling history are presented. A method to estimate the remaining energy given short-term cycling history is presented. This method differs from the traditional state of charge methods typically used in battery management systems by considering energy throughput more directly.

Evaluation of the Generating Capacity Adequacy of the Saudi Arabian Central Operating Area

The goal of the study presented in this article was to evaluate the adequacy of the generation capacity of the Central Operating Area in Saudi Arabia. The generating capacity adequacy was evaluated to examine the ability of the generating capacity of the system to meet the total system demand. Over the last five decades, several probabilistic methods have been developed as a means of conducting such an evaluation. Three probabilistic simulation techniques were used for the evaluation of the designated system for this study: analytical, sequential, and non-sequential Monte Carlo. A variety of reliability indices, such as loss of load expectation and loss of energy expectation, were obtained.

Athermal energy loss from x-rays deposited in thin superconducting films on solid substrates

When energy is deposited in a thin-film cryogenic detector, such as from the absorption of an x-ray, an important feature that determines the energy resolution is the amount of athermal energy that can be lost to the heat bath prior to the elementary excitation systems coming into thermal equilibrium. This form of energy loss will be position dependent and therefore can limit the detector energy resolution. An understanding of the physical processes that occur when elementary excitations are generated in metal films on dielectric substrates is important for the design and optimization of a number of different types of low-temperature detectors. We have measured the total energy loss in one relatively simple geometry that allows us to study these processes and compare measurements with calculation based upon a model for the various different processes. We have modeled the athermal phonon energy loss in this device by finding an evolving phonon distribution function that solves the system of kinetic equations for the interacting system of electrons and phonons. Using measurements of device parameters such as the Debye energy and the thermal diffusivity we have calculated the expected energy loss from this detector geometry, and also the position-dependent variation of this loss. We have also calculated the predicted impact on measured spectral lineshapes and have shown that they agree well with measurements. In addition, we have tested this model by using it to predict the performance of a number of other types of detector with different geometries, where good agreement is also found.

Adequacy Evaluation of Distribution System Including Wind/Solar DG During Different Modes of Operation

Keen interest in the development and utilization of renewable distributed generation (DG) has been currently observed worldwide. The reliability impact of this highly variable energy source is an important aspect that needs to be assessed as renewable power penetration becomes increasingly significant. Distribution system adequacy assessment including wind-based and solar DG units during different modes of operation is described in this paper. Monte Carlo simulation (MCS) and analytical technique are used in this work with a novel utilization of the clearness index probability density function (pdf) to model the solar irradiance using MCS. The results show that there is no significant difference between the outcomes of the two proposed techniques; however, MCS requires much longer computational time. The effect of islanding appears in the improvement of the loss of load expectation (LOLE) and loss of energy expectation (LOEE).

Power System Reliability Considering Combined Cycle Plants

In the nineties in Argentina, the growth of thermal power generation was mainly based on combined cycle plants. Currently, one problem associated with the use of combined cycle plants is the fact that they need to share the use of natural gas with commercial, industrial and domestic uses. Hence, the natural gas availability is becoming a critical issue. Therefore, power system reliability studies must consider fuel availability into the models, and as a consequence, reliability models must take into account the joint operation of electrical generation and natural gas systems. The aim of this paper is to evaluate the influence of combined cycle plants on reliability studies applied to system generation capacity and their dependency on natural gas availability. Monte Carlo simulation method is used to determine reliability indices such as Loss of Load Expectation, Loss of Energy Expectation, Loss of Load Frequency, and Loss of Load Duration. The IEEE RTS 96 test system is used as the base system, with is modified in order to incorporate combined cycle plants.

Supply Adequacy Assessment of Distribution System Including Wind-Based DG During Different Modes of Operation

Keen interest in the development and utilization of wind-based distributed generation (DG) has been currently observed worldwide. The reliability impact of this highly variable energy source is an important aspect that needs to be assessed as wind power penetration becomes increasingly significant. Distribution system adequacy assessment including wind-based DG units during different modes of operation is described in this paper. Monte Carlo simulation (MCS) and analytical technique are used in this work with a new implementation of the islanding mode of operation in the assessment. The results show that there is no significant difference between the outcomes of the two proposed techniques; however, MCS requires much longer computational time. Moreover, the effect of islanding appears in the improvement of the loss of load expectation (LOLE) and loss of energy expectation (LOEE).

Thixoforming of Carbon Steels: Inductive Heating and Process Control

The development of steel grades for the production of thixoformed parts made a great progress but the process itself is still difficult to control. The most critical point is the inductive heating of the billets to assuring a homogeneous distribution of the desired liquid fraction. One of the principle approaches is based on investigations of the thermo-physical properties of steel grades. These data are also used for numerical simulation of the inductive heating. From these results a mathematical model is derived and implemented in the heating chain for controlling the parameters that determines the billet temperature indirectly by computation and not by direct measuring of the temperature. Optimizing the coil geometry leads to an adapted magnetic field assuring a homogenous temperature distribution in the billet considering expected energy losses. We will also present new results of the liquid fraction within the billet as well as the electrical resistivity of the thixotropic steel at high heating rate corresponding to the industrial scale. Last but not least, some new parts made out of adapted steel will be shown.

HighpThadrons as probes of the central region of Au-Au collisions atSNN=200GeV

The energy loss of high ${p}_{T}$ partons propagating through a hot and dense medium is regarded as a valuable tool to probe the medium created in ultrarelativistic heavy-ion collisions. The angular correlation pattern of hadrons associated with a hard trigger in the region of ${p}_{T}~1\text{\ensuremath{-}}2$ GeV which exhibits a dip in the expected position of the away side jet has given rise to the idea that energy is lost predominantly to propagating collective modes (`Mach cones'). Recent measurements by the STAR Collaboration have shown that for a high ${p}_{T}>8$ GeV trigger the angular pattern of associate hadrons for ${p}_{T}>4$ GeV shows the emergence of the expected away side peak. These dijet events suggest that the away side parton may emerge occasionally without substantial energy loss. Since in such a back-to-back configuration one of the partons may travel through the central region of the fireball, the average in-medium pathlength is substantial and the expected energy loss is not only sensitive to the initial geometry of matter but also to the change of geometry due to expansion. We show that radiative energy loss is able to explain the dijet events provided that the expansion of the medium is taken into account.

Generation Adequacy Assessment of Power Systems by Time Series and Fuzzy Neural Network

In this paper, a new hybrid method for generation adequacy assessment of power systems is proposed. This method is based on the combination of time series and fuzzy neural network (FNN). The time series, as a spectrum analyzer, is used to determine the effective input features. The generation adequacy index of loss of energy expectation (LOEE) is selected as the output feature. These input and output features construct the training samples of the FNN. After training, it constructs a mapping function between input and output features, used to predict the adequacy index of the next time interval. Obtained results from extensive testing of the whole method on two practical power systems confirm the validity of the developed approach. It is shown that the proposed method can provide more accurate results than the conventional techniques, such as Monte Carlo simulation, time series, and artificial neural networks

Impact of unified power flow controllers on power system reliability

This paper examines the impact of a unified power flow controller (UPFC) on power system reliability. The UPFC is employed in the system to adjust the natural power sharing of two different parallel transmission lines and therefore enable the maximum transmission capacity to be utilized. The results of the investigations show a significant improvement in the system reliability by utilizing the UPFC. The improvement is measured using three reliability risk indices, namely, the loss of load expectation (LOLE), the loss of energy expectation (LOEE), and the system minutes (SM). The paper also presents a comparison between the effects of the UPFC and a thyristor controlled series capacitor on the system reliability.

Power system reliability enhancement using a thyristor controlled series capacitor

This paper examines the impact of a thyristor controlled series capacitor (TCSC) on power system reliability. In this application, the TCSC is employed to adjust the natural power sharing of two different parallel transmission lines and, therefore, enable the maximum transmission capacity to be utilized. In this context, a reliability model of a multi-module TCSC has been developed and incorporated in the transmission system. The results of the investigations show a significant improvement system reliability when utilizing the improvement is measured using the two indices of loss of load expectation (LOLE) and loss of energy expectation (LOEE).

Surface plasmons at MOCVD-grown GaN

We report on the first observation of surface plasmons at a GaN surface by high-resolution electron energy loss (HREEL) spectroscopy. Dipole scattering theory using self-consistent electron density profiles is employed to calculate the surface energy loss function and hence the expected energy loss spectra. The characteristic features of both the surface plasmons and the Fuchs-Kliewer (FK) surface optical phonons are well reproduced in the framework of this model. Fitting measured HREEL spectra allows us to give estimates of important semiconductor parameters such as electron density, electron mobility and band bending. Moreover, it is found that the plasmon damping strongly depends on primary beam energy. Similarly, the FK phonon damping and frequency are also affected by the variation of primary beam energy.

A simple model of photon transport

In this paper I describe a simple model of photon transport. This simple model includes: tabulated cross sections and average expected energy losses for all elements between hydrogen ( Z = 1) and fermium ( Z = 100) over the enrgy range 10 eV to 1 GeV, simple models to analytically describe coherent and incoherent scattering, and a simple model to describe fluorescence. This is all of the data that is required to perform photon transport calculations.

An educational software package for reliability evaluation of interconnected power systems

The reliability of the generating capacity in a power system is normally improved by interconnecting the system to another power system. This paper describes a Microsoft Windows 3.1 educational software package developed for the evaluation of the loss of load expectation (LOLE) and loss of energy expectation (LOEE) indices for up to three interconnected system generation facilities. Basic probabilistic techniques using recursive algorithms, the equivalent assisting unit approach and the probability array method are implemented. In addition, the software package is able to define and incorporate five types of load models, multi-state tie line models and three types of interconnection agreement schemes in the analysis. Comprehensive analysis tools for creating and viewing the various models and for performing sensitivity studies, including selective printing of results, are also included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An integrated approach to electric power system planning and cost of service allocation

Many methods have been proposed to allocate capacity related costs to the various customer classes in an electric power system. These methods are mainly deterministic. Deterministic techniques do not consider the stochastic nature of system components which actually affect the cost behaviour of the system. An important consideration in the process of cost allocation is to ensure that the method used follows the cost behaviour of the system studied. The cost behaviour is basically dependent on the methods and criteria used in system planning and operation. The criteria and planning methods used drives the development of the system which further drives the cost of future investment in the system. It is therefore highly desirable to use similar methods and criteria and to include the same variables which are considered in the system adequacy evaluation. Most large electric power utilities now use probabilistic techniques in their generation system planning. The most commonly used planning techniques are the Loss of Load Expectation (LOLE) and the Loss of Energy Expectation (LOEE) methods. Probabilistic techniques should also be used in the cost of service allocation process as these techniques are capable of incorporating the important factors which actually affect the system cost behaviour.

Energy Loss ofNe20Ions in Aluminum

The energy losses of 19.8- and 18.5-MeV /sup 20/Ne ions in aluminum have been measured by a new technique. The Doppler-shifted energies of gamma rays from the first excited state of /sup 20/Ne, produced in the /sup 12/C(/sup 12/C, alpha ) /sup 20/Ne reaction, were used to determine the Ne-ion velocities before and after passing through an aluminum foil. The results are in good agreement with expected energy losses, thus removing a discrepancy in earlier work. (auth)