Optimal Operation And Design Of Underground Power Cables In Cluster

With more and more underground cables are installed in power system in these years,multi-circuits cables are installed. Because of the expensive laying cost, enhancing the ampacity is one of many important challenges to be resolved urgently. This thesis described the investigation on enhancing current ampacity from two aspects.To develop a method and associated computer program that calculates the maximum current loadings of underground cables, a computational program on optimization design of underground power cables and optimal operation of underground power cable systems is complied. Comparing to the ampacity on different circuits has different ampacity, increasing ratio of transmission capacity of 110kV high voltage single-core and 10kV three-core XLPE cables is calculated. The purpose of this thesis is to develop a method and associated computer program that calculates the maximum current loadings of underground cables. The maximum sum of total current is taken as objective function. Constraint condition is that the temperature of any cables is lower than maximum permissible temperature. The finite volume method and artificial fish swarm algorithm are used to solve the optimum value. The solutions are optimum in terms of maximizing the total current that the cables may collectively carry.Multi-circuits cables usually lay in equal interval, but equal interval laying is not optimal operation state. This thesis gives the laying range, under prerequisite conditions. The maximum ampacity is taken as objective function. Constraint condition is that the temperature of any cables is lower than maximum permissible temperature. The thermal circuit method and artificial fish swarm algorithm are used to solve the maximum value. The solutions are optimum in terms of maximizing the ampacity that the cables may collectively carry. This thesis develops an optimization algorithm that generates convergent and optimum results for any number of cables, cable configurations and cable designs. The comparisons show that the optimal solutions obtained with the purposed method are superior to those obtained the standard method.The finite difference method based on combinatorial coordinates is used to compute the field of temperature and transmission capacity of cable system. The finite difference method is used to discrete thermal conduction differential equation. The combinatorial coordinate's method is used to solve boundary problem of cable system and soil area.Optimal operation and non-equal optimal design of underground power cables improve the utilization efficiency of power cables. Through analyzing the burial conditions of underground cable system, increasing ratio of transmission capacity of optimal operation and non-equal optimal design is computed. Good suggestions of operation and layout are presented.