基于双频激励的树型配电网单相接地故障测距方法研究

发布时间：2018-05-12 16:51

本文选题：带分支配电网 + 离线　；参考：《昆明理工大学》2017年硕士论文

【摘要】：配电网作为连接输电网和用户的纽带,在电力分配中扮演着重要的角色。但由于配电网分支较多,拓扑结构复杂、覆盖区域较广,加之近年来分布式电源(Distributed Generation,DG)的接入,传统的故障定位方法已经不适用。配电线路广泛应用在城镇、农村,它的运行情况直接影响到终端用户的用电质量。若能对配电网故障,尤其是带分支的配电网单相接地故障进行快速有效的定位,这对整个电力系统的稳定安全和经济运行都具有十分重要的意义。然而,现阶段配电网故障定位大多依赖需要精确对时的测距系统,对通信设备的要求较为严苛,成本较大,广大的农村配电网适应性较差。单相接地故障是配电网发生率最高的一类故障。发生单相接地故障时,非故障相电压上升为线电压,产生的过电压很可能导致设备烧毁击穿,也可能产生电弧,引起相间短路,从而扩大事故范围。许多年来,国内外学者对单相接地故障问题给予了很多的关注,提出了不同的故障定位方法。但由于配电网本身结构复杂和其他种种原因,故障定位的准确率一直不高。在实际应用中,行之有效的方式依旧采用拉闸选线结合人工巡线的方式查找故障点,这种方式不仅耗时耗力,降低电网的供电可靠性,也不契合当代的配电网向自动化的发展趋势。鉴于此,本文提出一种基于双频信号注入的配电网多分支故障定位方法。在此方法中,为避免谐波的干扰,选择在离线的状态下,用信号源向带分支配电网中注入两种不同频率的高频信号,通过对电压和电流信号的提取,并依据传输方程,遍历线路全长,最后利用诊信方程求解出故障距离。本文分别对直配线和带分支结构的配电网单相接地故障测距进行建模仿真,基于在相异千赫兹的诊信频率下,真故障的值不变,伪故障的值不同的判据,有效的测出真实故障距离,剔除了等效故障。仿真表明,该方法能快速、准确的实现直配线和带分支配电线路故障的有效辨识和故障距离的测定,是一种比较有效的测距方法。
[Abstract]:As a link between transmission network and users, distribution network plays an important role in power distribution. However, due to the large number of branches, complex topology, wide coverage and the access of distributed Generation (DG) in recent years, the traditional fault location method is no longer applicable. Distribution line is widely used in towns and villages, its operation directly affects the power quality of the end users. If the fault of distribution network, especially the single-phase grounding fault with branches, can be located quickly and effectively, it will be of great significance to the stability, safety and economic operation of the whole power system. However, at this stage, most of the distribution network fault location depends on accurate and timely location system, the requirements of the communication equipment is more stringent, the cost is high, the wide range of rural distribution network adaptability is poor. Single-phase grounding fault is one of the most common faults in distribution network. When a single-phase grounding fault occurs, the non-fault phase voltage rises to a line voltage, which may cause the equipment to burn out and break down, also may produce arc, which will cause inter-phase short circuit, thus extending the range of accidents. For many years, scholars at home and abroad have paid much attention to the problem of single-phase grounding fault, and put forward different fault location methods. However, due to the complexity of distribution network structure and other reasons, the accuracy of fault location has not been high. In the practical application, the effective way still adopts the way of selecting the line by pulling and combining with the manual inspection to find the fault point, this way not only time-consuming and labor-consuming, but also reduces the power supply reliability of the power network. Also does not accord with the contemporary distribution network to the automation development trend. In view of this, a multi-branch fault location method based on dual-frequency signal injection is proposed in this paper. In this method, in order to avoid harmonic interference, two kinds of high frequency signals with different frequencies are injected into the distribution network with branch by signal source under the condition of off-line, by extracting the voltage and current signals, and according to the transmission equation, The whole length of the line is traversed, and the fault distance is solved by using the diagnostic signal equation. This paper models and simulates single-phase grounding fault location of distribution network with direct distribution line and branch structure, based on the criterion that the value of true fault is invariant and the value of pseudo-fault is different under the different KHz diagnostic frequency. The true fault distance is effectively measured and the equivalent fault is eliminated. The simulation results show that this method can quickly and accurately identify the faults of direct distribution lines and distribution lines with branches and determine the fault distance. It is a more effective method for location.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM755

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