This paper probes the impact of utilizing an IPFC on the reliability indices of interconnected powersystems. First, a concise presentation of IPFC and its structure are provided and the reliability model of two unequ...
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This paper probes the impact of utilizing an IPFC on the reliability indices of interconnected powersystems. First, a concise presentation of IPFC and its structure are provided and the reliability model of two unequally-rated parallel transmission lines equipped with IPFC is then extracted. The assumed IPFC is composed from two parallel converting bridges associated with each line. Afterwards, based-on equivalent assisting unit approach, different commonly-used adequacy indices including the loss of load expectation (LOLE), loss of energy expectation (LOEE) and system minutes (SM) are calculated. A set of numerical analyses are conducted to illustrate the sensitivity of these indices with respect to different parameters.
This paper proposes a method for unit commitment in restructured powersystems with high penetration of wind farms. As wind is an intermittent source of energy and can not be predicted with high accuracy, reliability ...
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This paper proposes a method for unit commitment in restructured powersystems with high penetration of wind farms. As wind is an intermittent source of energy and can not be predicted with high accuracy, reliability of wind farms compare to conventional power plants is lower. By increasing penetration of wind farms in generation system, reliability of powersystem will decrease. Therefore, reliability constraint should be added to unit commitment (UC) formulation. On the other hand, wind is a green source of energy; additionally environmental crisis is very important issue in the 21 st century. By adding emission constraint to UC, wind energy will be valued. Both reliability and emission constraints are acing as fuzzy constraints. It means that if the UC solution exceeds these constraints limits, that configuration of UC will be penalized by adding augmented cost to total UC cost. To implement these constraints to UC, simulated annealing (SA) has been used because it converges very well under complex and nonlinear constraints. At the end, if any wind farm considered to be off in UC, a must run constraint will make them on and calculate reliability effect of the recommitted wind farm on generation system and decrease from the capacity of the most expensive thermal units equal to the calculated effect of newly committed wind farm on system reliability. Then wind farms that recommitted will be paid 80 percent of the cheapest committed unit in that period. In this way, wind farms will be supported wisely and free power market conditions will be remain unchanged.
This paper presents a novel approach to solve the constrained unit commitment problem using the Selective Self-Adaptive Ant Colony Optimization (SSACO) for improving search performance by automatically adapting ant po...
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ISBN:
(纸本)9789810594237
This paper presents a novel approach to solve the constrained unit commitment problem using the Selective Self-Adaptive Ant Colony Optimization (SSACO) for improving search performance by automatically adapting ant populations and their transition probability parameters, which cooperates with the Candidate Path management Module (CPMM) and the Effective Repairing Heuristic Module (ERHM) in reducing search space and recovering a feasible optimality region so that a high quality solution can be acquired in a very early iterative. A new concept of the Relativity Pheromone Updating (RPU) is also introduced to provide a reasonable evaluation of the pheromone trail intensity among the agents. The proposed SSACO method not only enhances the convergence of search process, but also provides a suitable number of the population sharing which conducts a good guidance for trading-off between the importance of the visibility and the pheromone trail intensity. The proposed method has been performed on a test system up to 100 generating units with a scheduling time horizon of 24 hours. The numerical results show the most economical saving in the total operating cost when compared to the previous literature results. Moreover, the proposed SSACO topology can remarkably speed up the computational time of ant colony optimization, which is favorable for a large-scale UC problem implementation.
This paper presents modeling of series static voltage restorer (SSVR) in load flow calculations for steady-state voltage compensation. An accurate model for SSVR is derived to use in load flow calculations. The rating...
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This paper presents modeling of series static voltage restorer (SSVR) in load flow calculations for steady-state voltage compensation. An accurate model for SSVR is derived to use in load flow calculations. The rating of this device as well as direction of required reactive power injection to compensate voltage to the desired value (1 p.u. ) is derived and discussed analytically and mathematically using phasor diagram method. Since performance of SSVR varies when it reaches to its maximum capacity, modeling of SSVR in its maximum rating of reactive power injection is derived. The validity of the proposed model is examined using two standard distribution systems consisting of 33 and 69 nodes, respectively. The best location of SSVR for under voltage problem mitigation in the distribution networks is determined. The results show the validity of the proposed model for SSVR in large distribution systems.
This paper presents a development of the enhanced ant colony optimization (EACO) based on a novel approach of the relativity pheromone updating strategy (RPUS) for solving constrained unit commitment problem which coo...
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This paper presents a development of the enhanced ant colony optimization (EACO) based on a novel approach of the relativity pheromone updating strategy (RPUS) for solving constrained unit commitment problem which cooperates with the candidate path management module (CPMM) embedded the effective repairing heuristic module (ERHM) in reducing search space and recovering a feasible optimality region so that a high quality solution can be acquired in a very early iterative. The adoption of RPUS not only enhances the search convergence of EACO, but also provides relatively pheromone information that is suitably exploited for a good guidance of search process. The EACO algorithms have been performed on a test system up to 100 generating units with a scheduling time horizon of 24 hours. The numerical results show better economical saving in the total operating cost when compared to the previous literature results. Furthermore, the proposed EACO topology can remarkably speed up the computation time of ant colony optimization algorithms, which is favorable for a large-scale UC problem implementation.
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