Loss minimization of distribution feeders: optimality and algorithms

Abstract

Determining open switch positions for the minimum-loas configuration of a radial distribution system is a discrete optimization problem. This paper presents a global optimality condition of the problem and two algorithms: one is based on the uniformly distributed load model and the other on the concentrated current (or power) demand model. The derivation of the ~ptimality condition relies on a concept of "basic" current profiles of feeder sections and a transformation of the optimization problem. In the first algorithm, a closed form of the minimum-loss open point of a feeder pair can be found since the loss function is piece-wise parabolic. The algorithm obtains the optimal solution when the minimum is obtained for every feeder pair. In the second algorithm, a similar procedure i s performed by moving open points, one at a time, from an actual switch position to another until no further loss reduction can be achieved. The proposed algorithms can be utilized as an on-line aid to distribution system operators. ABSTRACTDetermining open switch positions for the minimum-loas configuration of a radial distribution system is a discrete optimization problem. This paper presents a global optimality condition of the problem and two algorithms: one is based on the uniformly distributed load model and the other on the concentrated current (or power) demand model. The derivation of the ~ptimality condition relies on a concept of "basic" current profiles of feeder sections and a transformation of the optimization problem. In the first algorithm, a closed form of the minimum-loss open point of a feeder pair can be found since the loss function is piece-wise parabolic. The algorithm obtains the optimal solution when the minimum is obtained for every feeder pair. In the second algorithm, a similar procedure i s performed by moving open points, one at a time, from an actual switch position to another until no further loss reduction can be achieved. The proposed algorithms can be utilized as an on-line aid to distribution system operators.

Line Switch Unit Commitment for distribution Automation Systems using Neural Networks

“…After isolating the faulted section by opening its boundary line switch, the feeder circuit breaker is closed to restore the service of upstream line sections in one minute after fault occurrence. The downstream line sections are then restored by closing the open tie switch in 5 minutes after verifying the load demand to be restored with the reserve capacity of the supporting feeder [9], [10], [11]. The mean time to repair a faulted section is assumed to be 60 minutes.…”

Reconfiguração ótima de sistemas de distribuição para minimização de perdas de energia

“…Com este propósito, podem ser encontradas na literatura metodologias que utilizam técnicas de otimização discreta como Branch and Bound (Merlin and Back, 1975). No entanto, devido à natureza combinatória do problema de reconfiguração, este método requer a análise de um grande número de configurações para sistemas reais (Liu et. al., 1989;Radha et.…”

Distribution service restoration using chaotic optimization and immune algorithm

“…So it is difficult to solve in a very short period by traditional optimization method. At present, artificial intelligence techniques are widely used, and have demonstrated many successful applications in the area of power systems, for example tabu search method [2,3], fuzzy theory [4,5], expert system [6,7], genetic algorithm [8,9] and so on. Among them, if only expert system it is difficult to make a complete 2010-10-12, Doctoral Fund of Chongqing University of technology (076026) Authors are with the school of Electronic Information and Automation in Chongqing University of technology.Chongqing,400054,China (E_mail:cn_lsl@tom.com.…”