Abstract
In this paper an improved over current relay coordination protection technique is proposed. The proposed technique eliminates the sympathetic/nuisance tripping in an interconnected distribution system. Nuisance trippings are eliminated by incorporating the additional selectivity constraints in conventional over current relay coordination problem. Whenever the fault is cleared only from one end of the line in bidirectional fault feed lines, transient network configuration comes into existence. Transient network configuration causes the redistribution of fault in the distribution system and leads to further nuisance tripping of relays. This problem in this paper is solved by minimising the operating time gap between primary relays located at near end and far end of a faulty line to the best minimum possible value. The differential search algorithm is applied for optimization of highly non-linear over current relay coordination problem in this paper. The result presented in this paper shows that the proposed over current relay coordination technique is immune against the sympathetic/nuisance tripping and operating time difference between primary relays at near end and far end is also minimised within acceptable time margin successfully.
Regional logistics changes. Locational dynamics and strategies in physical distribution - a transatlantic comparison. The paper discusses locational dynamics of freight distribution firms at the regional level, as a consequence of changes in logistics network configuration and related requirements for placing distribution centres. The empirical basis is provided by two case studies, carried out in Germany and in Northern California (USA). Both cases are subject to comparative analysis, regarding location choice and context, corporate strategy and regional policy and planning.
Optimal Relays Coordination Efficient Method in Interconnected Power SystemsIn this paper an efficient method for optimal overcurrent relay coordination is proposed. In the proposed method using genetic algorithm, an objective function (OF) is developed to solve the problem of miscoordination for six pairs short circuit fault currents. The new OF is improved to be simple, optimal and efficient. This technique takes into account the changes in network configuration. The efficiency of the proposed technique is demonstrated by comparing the results of two different networks namely typical 8-bus & IEEE 30-bus systems with those obtained using the recently developed techniques.
Optimal Relays Coordination Efficient Method in Interconnected Power Systems
