【作者】 张芳；

【导师】 曾祥君； 毕大强；

【作者基本信息】 长沙理工大学 ， 电气工程， 2015， 硕士

【摘要】 船舶、飞机和空间站等电力系统均属于独立电力系统范畴。独立电力系统运行环境恶劣,容易受到外部扰动。环形、区域配电等供电方式中的重要设备可以从线路的两个方向获得电源,从而具有较高的供电连续性和可靠性。同时,先进的保护方法和故障恢复技术是提高独立电力系统生存性的重要途径。论文基于无通道保护及智能恢复的思想,针对目前独立电力系统保护及智能恢复研究中存在的问题,着重研究了环网系统保护和直流区域系统多目标故障恢复方法。论文首先分析对比了独立电网配电结构特点,利用MATLAB对一典型的环形电网结构建立了较为精确的模型,并对模型在不同运行方式下的短路情况进行了仿真分析。在此基础上,分析了独立电网传统三段式电流保护方法,进而提出了三种改进保护方法：第一种是改进的基于电流时间原则的保护方法,该方法依靠对端断路器断开后,本端保护按照前后级保护装置动作时限的级差来实现保护的选择性；第二种是基于电流比值的电流保护加速方法,该方法利用短路故障和线路一侧保护跳闸引起另一侧支路的电流变化,以及该变化的前后比值来判断故障区间,最终实现相继速动。第三种是基于电流突变时间的电流保护加速方法,该方法利用故障发生和线路一侧断路器跳闸引起的另一侧支路电流变化,和该变化所具有的时间特性判断故障区间,来实现故障线路两端保护的相继速动。研究了独立电力系统直流区域配电系统的故障恢复过程。以负荷供电量最大和开关动作次数最小作为目标函数,建立了一种用于直流区域配电系统的多目标故障恢复模型。然后将不同量纲的目标函数进行单位化,再通过层次分析法把这些已单位化的函数进行综合,最后利用整数规划方法,对综合目标函数进行优化求解,得到最优开关动作序列。相比传统的基于电流时间原则的保护方法,所提保护方法不仅不需要通信通道,而且能进一步缩短切除故障线路的时间,保证重要负载的供电连续性。论文的研究发展了独立电力系统无通道保护理论,增强了系统在故障情况下的生存能力,具有重要的理论和实用价值。直流区域电网重构的分析方法,也对今后直流配电网的研究起到了一定的借鉴作用。更多还原

【Abstract】 The power system used on shipboard, airplane or space station, for example, is classified as isolated power system (IPS). IPS with bad operation environment is vulnerable to external disturbances. The important equipments in loop power distribution systems and zone distribution system have the advantages of high power supply continuity and reliability because the systems can obtain power supply from two directions. Moreover, the advanced protection and reconfiguration technology are important means to improve the survivability and reliability of IPS. Based on the ideas of non-communication protection and intelligent restoration, the protection of loop power distribution and the multiobjective intelligent service restoration method of DC zone distribution are studied.Firstly, the network structure characteristics of IPS are analyzed. A typical loop power distribution has been established by MATLAB, and the short circuit situation under different operation modes have been analyzed by simulation. On the basis, the traditional three section current protection method of IPS is analyzed, three kinds of protection methods are presented by using different criteria. The first one is an improved directional over-current based time-graded protection. In this method, the local relay achieves the selectivity by time coordination of protection device after the remote break of the line has been disconnected. The second one is an accelerated action method based on ration signal of current. The changing of current through the local relay is adopted when the fault occurs and the remote breaker of the line is tripped. The method uses the current ratio criterion of the accelerated over-current protection to determine the fault zone, and then accelerated trip of the local break. The last one is a new accelerated action method based on the remote breaker operating time. In the method, the changing of current through the local relay is adopted when the fault occurs and the remote breaker of the line is tripped, and the time characteristics of this changing are used to determine the fault zone, and then accelerated trip of the local break.The restoration process of DC zone distribution of IPS is researched. A multiobjective model for fault restoration of DC zone distribution system is established to maximize numbers of load power supply and minimize the time of switch operation. In this paper, the objective functions of different dimensions are normalized, and these objective functions are integrated by using the analytic hierarchy process (AHP). Then the integer programming (IP) method is used to optimize the integrated objective function, and the optimal switch operation sequence is obtained finally.Compared with the traditional three-section current protection method, the proposed protection methods do not need communication channel, but also can further shorten the time of cutting off the fault line, and ensure the continuity of power supply. This paper develops the theory of non-communication protection for IPS, which could be a powerful tool for enhancing the survival of IPS under complex situations. The work of these protection methods is of great theoretic and practical value. And the reconstruction method of DC zone distribution is a good reference for study on DC power distribution network.更多还原