基于互相关算法的小电流接地系统单相接地故障综合选线方法研究

发布时间：2018-05-05 17:47

本文选题：小电流接地系统 + 单相接地故障　；参考：《山东大学》2015年硕士论文

【摘要】：随着社会经济的快速发展,电力用户对供电可靠性的要求越来越高,对整个电力系统的安全性和可靠性提出了新的、更高的要求。目前,国内6kV～35kV配电网大多数采用小电流接地系统,主要包括中性点不接地系统、中性点经消弧线圈接地系统和经中电阻接地系统。在配电网中,发生单相接地故障的机率占80%以上,当小电流接地系统发生单相接地故障时,由于无法形成短路回路,故障仅为线路对地的容性电流,电流值一般较小。因单相接地时系统线电压仍保持对称,所以允许系统可带故障运行1-2小时,但长时间的带接地故障运行会对配电网及设备产生负面影响。这就要求在配电线路发生单相接地故障时,要尽可能快速、准确地判断出故障线路并隔离处理,这也推动了配电线路单相接地故障选线技术的进一步发展。本课题研究基于暂态、稳态、高频及“S注入”法的多种选线原理的优缺点,研究自适应动态贡献率算法,根据对算法适用域的特征量分析,解决了多种算法的权重动态分配问题,使系统中的多种算法能够动态的自适应不同的运行方式和接地方式,达到对各种算法动态贡献率的分析,最终得到准确的故障馈线。通过各种对稳态量、暂态量、高频特征量及注入法中各故障分量的互相关分析,得到故障馈线与非故障馈线的相互关系,达到祛除对故障电流门槛的依赖,解决困扰多年以来零序电流门槛的设定带来的麻烦。同时也降低了对零序电流互感器精度的要求,符合目前变电站的实际情况。利用小电流系统单相接地时的各特征量,给出小电流接地选线总体设计方案,同时完成小电流接地选线系统的硬件、软件方案设计,建立小电流接地系统单相接地故障选线系统,最后通过测试来检验该系统的有效性和实用性。
[Abstract]:With the rapid development of social economy, the demand of power supply reliability is becoming higher and higher, which puts forward new and higher requirements for the security and reliability of the whole power system. At present, small current grounding systems are mostly used in 6kV~35kV distribution networks in China, including neutral ungrounded system, neutral grounding system through arc-suppression coil and mid-resistance grounding system. In the distribution network, the probability of single-phase grounding fault is more than 80%. When the single-phase grounding fault occurs in the low-current grounding system, the fault is only capacitive current of the line to the ground, and the current value is generally small because the short-circuit can not be formed. Because the line voltage of single-phase grounding system is still symmetrical, the system can run with fault for 1-2 hours, but the long-time operation with grounding fault will have a negative impact on the distribution network and equipment. This requires that the fault line should be judged and treated as quickly and accurately as possible when the single-phase grounding fault occurs on the distribution line, which also promotes the further development of the single-phase grounding fault line selection technology of the distribution line. Based on the advantages and disadvantages of transient, steady, high-frequency and "S-injection" methods, the adaptive dynamic contribution algorithm is studied in this paper. It solves the problem of dynamic weight allocation of various algorithms, and makes various algorithms in the system dynamically adapt to different operation modes and grounding modes, so that the dynamic contribution rate of various algorithms is analyzed, and the accurate fault feeder is finally obtained. Through the cross-correlation analysis of steady state, transient, high frequency characteristic and each fault component in injection method, the relationship between fault feeder and non-fault feeder is obtained, and the dependence on fault current threshold is eliminated. Solve the trouble caused by the setting of zero-sequence current threshold for many years. At the same time, the precision requirement of zero sequence current transformer is reduced, which accords with the actual situation of substation. Based on the characteristics of single-phase grounding of small current system, the overall design scheme of line selection for small current grounding is given, and the hardware and software design of line selection system with small current grounding is also completed. The single-phase grounding fault line selection system of small current grounding system is established. Finally, the validity and practicability of the system are tested.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM862

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