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The impact of a pulse load charging event on a notional all-electric ship is investigated through simulation in the context of uncertainty in the parameters of the system and event. In order to efficiently carry out the study, the system is modeled on a large-scale parallel processor simulator. A surrogate modeling approach is used to characterize the behavior of the system for the purposes of sensitivity...
In power system planning and operation, accurate assessment of reliability worth is essential for making informed decisions. One common simplification when modeling power system reliability is assuming constant failure rates and non time-varying restoration times. However, historical outages show differently; failure rates and restoration times for especially overhead lines are dependent upon time-varying...
A Markovian approach already developed in a previous paper by some of the authors to evaluate the energy production and power availability of a wind turbine is utilized to size a hybrid wind-diesel stand alone system. The wind turbine power time variability is taken into account by means of a discrete reduced number of contiguous power classes, each corresponding to an opportune range of values, starting...
In operation studies of distribution networks, the restoration problem is solved using optimization techniques. However, in planning studies, such as reliability evaluation, the restoration problem is solved considering engineering judgment. Therefore, there is a mismatch between the restoration modeling used in the operation of the network and in the planning studies. This paper presents a method...
Multi-stage decision making, a fundamental tenet of stochastic programming, resonates well with the practice of the electricity markets. The day-ahead market, used to commit the generators, bears uncertainty in the power demand and physical conditions of the generators and transmission lines. The situation becomes less uncertain in the real-time market, where the dispatch is decided. Although traditional...
In this study, unit commitment (UC) problem is solved for an optimum schedule of generating units based on the load data forecasted by using artificial neural network (ANN) model and ANN model with autoregressive (AR). Low-cost generation is important in power system analysis. Under forecasting or over forecasting will result in the requirement of purchasing power from spot market or an unnecessary...
This paper analyzes the generation adequacy of Mexico's National Interconnected Power System (MNIPS). The algorithm used computes loss of load expectation (LOLE) and loss of energy expectation (LOEE) indexes. These indexes are calculated through an analytical (recursive) method and are then compared with values recommended by the North American Electric Reliability Council (NERC). The period of study...
This paper proposes a new estimation technique of the load duration curve (LDC) which takes into account recent modifications of the load demand in the Tunisian power system (STEG) related to the increasing of the air conditioning load. This approach is based on the estimation of the hourly peak load distribution by asymmetric generalized Gaussian distribution (AGG). Numerical results indicate that...
Fuel diversification implies the selection of a mix of generation technologies for long-term electricity generation. The goal is to strike a good balance between reduced costs and reduced risk. The method of analysis that has been advocated and adopted for such studies is the mean-variance portfolio analysis pioneered by Markowitz (1952). However the standard mean-variance methodology, does not account...
There are two fundamentally different forms of uncertainty in power system reliability assessment. Aleatory uncertainty arises because the study system can potentially behave in many different ways. The component failure and repair processes are random and create variability known as aleatory uncertainty. There are also limitations in assessing the actual parameters of the key elements in a reliability...
This paper demonstrates a methodology for the optimal use of phase shifting transformers (PSTs) for the minimisation of the risk of congestion on power system lines. The methodology proposes as a first step the use of Monte-Carlo simulation for the assessment of the power flow distributions in the lines. It is shown that by using PSTs these distributions are shifted by specific factors that can be...
This paper presents a new methodology for determining the optimal number of spare transformers (pole-mounted type) to be stored in regional centers of distribution companies, in order to balance reliability and cost criteria. The proposed method is based on chronological Monte Carlo simulation to evaluate reliability indices like probability, frequency and duration of failures in distribution systems...
Electric utilities schedule power transformers in high voltage load stations (customer delivery or regional supply systems) for planned outages such as unit refurbishment, unit replacement, etc. that may last for a few weeks. During the planned outage time, companion units may fail causing a complete loss of supply to customers. Mobile unit transformers (MUT's) could be used in these emergency situations...
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