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The paper presents a practical dynamic security region (PDSR) based dynamic security risk assessment and optimization model for power transmission system. The cost of comprehensive security control and the influence of uncertainties of power injections are considered in the model of dynamic security risk assessment. The transient stability constraints and uncertainties of power injections can be considered...
Detailed maintenance modeling is indispensable for utilities to determine optimum maintenance policy. Traditional reliability studies assume that transition rates or probabilities in Markov models are accurate. However, in reality, reliability data is either insufficient or mixed with uncertainty. This paper intends to utilize fuzzy set theory to represent parameters for Markov and semi-Markov processes...
Cost-effective maintenance scheduling of power system equipment is critical, especially with present economic scenario of power industry. Apart from long-term maintenance policy, asset planners need to come up with revised short term maintenance strategies mainly due to the shrinking budget allocations for various reasons. The problem may be formulated as follows: if it is the same availability of...
In order to schedule the choice of maintaining or refurbishing MV equipment, an electrical utility may study ageing effects on different pieces of such equipment. In this paper, the analysis is based on record of outages (MV power cuts) during several years where causes of outages are noticed (and ages of pieces of equipment are also known). Failure rate versus age estimation results are given for...
The objective of this paper is to introduce analytical models for accurate prediction of failure probabilities of existing shield wires and to recommend a time window for wire replacement at an acceptable failure threshold. Ductile and strength tests results and failures records of shield wires were examined to determine the trend of wires deteriorations as they age. Since most of failures occurred...
Heuristic methods have demonstrated the potential to and good feasible solutions, but not necessarily optimal. The success of such methods is related to their ability of avoiding local minima by exploring the basic structure of each particular problem. These methods can provide high quality solutions, within an acceptable CPU time, even for large-scale problems. This paper presents a new methodology...
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...
This paper reports new results in adopting entropy concepts to the training of mappers such as neural networks to perform wind power prediction as a function of wind characteristics (mainly speed and direction) in wind parks connected to a power grid. Renyi's Entropy is combined with a Parzen Windows estimation of the error pdf to form the basis of three criteria (MEE, MCC and MEEF) under which neural...
This paper illustrates the challenges associated with risk assessment for reinvestments decisions. A holistic framework for risk assessment in electricity distribution systems will be described first and then used to structure the analysis and decision making in a case study concerning cable reinvestment. These decisions are generally multi criteria decisions, including risks related to e.g.; economy,...
Wind is being recognized as an encouraging and cost effective generation source both in large grid connected systems and small isolated applications. The actual benefits obtained from utilizing wind energy for electric power generation can be investigated using reliability and economic evaluation techniques. The focus of these techniques is usually directed to the areas of reliability and the investment/operation...
This paper addresses the generation expansion-planning problem describing a model that generation companies can use to get insight to this problem and to more completely study and characterize different investment decisions. In the last 20 years, the generation activity evolved from a situation in which it was part of vertical companies to unbundled market agents that face a much more risky and uncertain...
Interruptions in the supply of electricity to customers are inevitable but it is important to measure, monitor and minimize the costs incurred. In this paper it is shown that customer interruption costs (CIC) depend on a variety of factors. They include the type of country and locality in which the interruptions occur. Actual costs depend on the types of appliances that are interrupted and the sectors...
Wind energy on a power system alters the unit commitment and dispatch problem, as it adds a stochastic element due to the uncertainty of wind power forecasts. By explicitly taking into account the stochastic nature of wind power, it is expected that better schedules should be produced, thereby reducing costs on the system. This paper compares a stochastically optimised unit commitment and dispatch...
Uncertain wind power forecasts is a disadvantage in an electricity market where the majority of the trading is performed several hours before the actual delivery. This paper presents a model which can be used to study how changes in the trading arrangement-in particular changing the delay time between closure of the spot market and the delivery period or changing the imbalance pricing system-would...
We propose in this paper a novel approach for identifying rare events that may endanger power system integrity. This approach is inspired by the rare-event simulation literature and, in particular, by the cross-entropy (CE) method for rare- event simulation. We propose a general framework for exploiting the CE method in the context of power system reliability evaluation, when a severity function defined...
This paper introduces the characteristics of relationship between probabilistic reliability (LOLE; loss of load expectation) and deterministic reliability (SRR; supply reserve rate) for 2008 and 2010 years in Korea power system. Korea power system has been using the loss of load expectation criterion (0.5 days/year) to determine the adequacy of installed capacity (ICAP) requirement. The criterion...
The Brazilian power grid has traditionally been designed and operated by means of a deterministic reliability criteria set. Although these criteria have successfully eliminated system constraints, they have also entailed higher costs, especially those concerning operation planning. That happens because such deterministic criteria allow quantitative and not- qualitative analysis. Their essential weakness...
This paper presents a probabilistic reliability planning method for transmission systems. The core of the method is the quantified reliability evaluation technique, which is based on Monte Carlo simulation for transmission and generation and an analytical multiple-state model for an HVDC system. The planning procedure includes comparison among reinforcement alternatives, effect study of retired components,...
This article is an extension of the work presented earlier, which compared and analyzed the economics of alternative maintenance plans. The proposed model combines genetic algorithms with Monte Carlo simulation to arrive at the most economic investment timing. The approach described earlier was characterized by a very long computing time making it difficult to use. This paper addresses several issues...
In this paper, a systematic risk-based transmission line expansion approach is studied. The approach addresses three objectives: load-driven expansion, security-enhancement expansion and risk-based expansion. The first problem identifies transmission expansions necessary to correct inadequacy; the second problem identifies transmission expansion necessary to correct insecurity; the third problem balances...
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