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A Power System Stabilizer (PSS) is one of the most widely used power system controllers to enhance the stability of the power systems. In this paper, a new optimization technique for tuning PSSs in multi machine power system is presented. It is used to tune five PSSs in a 39-Bus IEEE New England network to enhance the small signal stability. The technique used is based on Low Discrepancy Sequence...
This paper addresses the problem of predicting a wind farm's power generation when no or few statistical data is available. The study is based on a time-series wind speed model and on a simple dynamic model of a DFIG wind turbine including cut-off and cut-in behaviours. The wind turbine is modeled as a stochastic hybrid system with three operation modes. Numerical results, obtained using Monte-Carlo...
Con Edison's distribution systems supply power to more than 3 million customers in New York City and Westchester County. About 85% of the load in the Con Edison service territory is supplied by underground low-voltage network systems. The reliability of underground low-voltage network systems is extremely high and Con Edison uses Network Reliability Index (NRI) programs - the Contingency program and...
This paper focuses on the application of risk-based models to cogeneration system planning in the presence of uncertainties. Starting from the electrical and thermal load patterns, and the electricity and gas prices for a reference year, the uncertain variables for the successive years of analysis (demand and energy prices) are represented by using average values and covariance matrices, taking into...
This paper proposes an optimization algorithm suitable to choose the optimal number and position of the measurement devices in active distribution networks. In active distribution networks distributed energy resources may be controlled and the topology modified to optimize power flows and to solve critical contingencies. The proposed algorithm, based on the techniques of the dynamic programming, has...
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...
This paper presents a new methodology for assessing both reliability and well-being indices for composite generation and transmission systems. Firstly, a transmission network reduction is applied to find an equivalent for assessing composite reliability for practical large power systems. After that, in order to classify the operating states, Artificial Neural Networks (ANNs) based on Group Method...
More and more wind power is being integrated into power grids in recent years. However, due to its intermittent characteristic, it is usually difficult to determine the appropriate penetration level to ensure a specified reliability requirement. For this purpose, the proper calculation of wind power capacity credit is of particular importance which is useful in both operations and planning stages...
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 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...
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...
The output of a power system analysis mostly requires extensive knowledge and correct handling of input uncertainties. Analytical approaches often depend on simplified models whereas Monte Carlo based sampling methods are often time consuming. This paper presents an uncertainty analysis based on a limited number of well chosen samples which are used to model a stochastic response surface, based on...
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...
There is growing interest in designing and applying deterministic techniques that include probabilistic considerations in order to assess increased system stress due to the restructured electricity environment. The overall reliability framework proposed in this paper incorporates the deterministic N-1 criterion in a probabilistic framework, and results in the joint inclusion of both adequacy and static...
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...
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