适用于含DG配网的充分式方向保护研究

发布时间：2018-04-24 08:49

本文选题：分布式发电 + 方向保护　；参考：《东南大学》2015年硕士论文

【摘要】：随着化石能源危机以及环境问题日益严重,分布式发电(DG)技术越来越受到人们的重视。分布式发电以其灵活、经济、可靠等优点,使其接入配电网成为不可避免的趋势和发展方向。但分布式发电的应用改变了传统配电网的拓扑结构,从单电源的辐射结构改变为多电源的复杂网络,改变了系统故障电流的大小,潮流的流向,某些线路甚至出现了潮流双向流动的现象。根据IEEE1547规定,配电网发生故障后必须立即切除DG,恢复配电网络原有的辐射状结构并以三段式电流保护动作切除故障。这即损害了DG发电商和DG用户的利益,又在一定程度上限制了新能源发电产业的发展,这也从另一方面凸显出当下研究含DG配电网保护方案的必要性。本文从DG对配电网保护影响着手,分析了含DG配电网方向保护的研究现状,并指出其不足及待改进的地方。在此基础上,从保护策略层面出发,提出一种“充分式”保护策略,其基本思想是基于配电网现有的条件,充分利用不完整的网络信息,挖掘适用于含DG配电网的充分式故障定位和隔离方案,不要求该策略能够解决配电网所有的问题,但是必须能够解决大部分甚至绝大部分的问题。相比于传统的保护策略,该保护策略更适用于目前的配电网环境。依据“充分式”保护思想,从配电网络整体出发,深入研究含DG配电网的故障电流特点。针对配电网中的不对称故障采用基于负序电流幅值、相位的故障方向判据,针对配电网中的对称故障采用基于正序故障电流幅值、相位的故障方向判据,并提出相应的故障区域判定方案。然后,在已确定的故障区域内,以负荷电流相位为基准,通过对比线路两端故障后的电流相位来准确定位故障区间。通过该方案不仅能够实现对故障区间的准确定位,还在一定程度上减少了配电网的通信量。最后,总结出基于“充分式”方向保护的配电网保护方案,并详细分析了其结构和流程。在Matlab/Simulink平台上建立含DG配电网模型,对其进行动态仿真。结合理论分析和仿真,结论表明该方案在配电网的不同故障类型下均有较强的适应性,能够迅速、准确地切除配电网故障。
[Abstract]:With the crisis of fossil energy and the increasingly serious environmental problems, distributed power generation (DG) technology has been paid more and more attention. Because of its advantages of flexibility, economy and reliability, distributed generation has become an inevitable trend and development direction. However, the application of distributed generation has changed the topology of traditional distribution network, from the radiation structure of single power source to the complex network of multiple power sources, and changed the magnitude of system fault current and the flow direction of power flow. Some lines even appear the phenomenon of two-way flow of tidal current. According to IEEE1547, the distribution network must be excised immediately after failure, the original radiation structure of distribution network should be restored and the fault should be removed by three-segment current protection. This not only damages the interests of DG generators and DG users, but also restricts the development of new energy generation industry to a certain extent, which also highlights the necessity of current research on DG distribution network protection scheme. Based on the influence of DG on distribution network protection, this paper analyzes the present situation of direction protection with DG distribution network, and points out its deficiency and the place to be improved. On this basis, from the level of protection strategy, a "sufficient" protection strategy is put forward. Its basic idea is to make full use of incomplete network information based on the existing conditions of distribution network. Mining is suitable for adequate fault location and isolation scheme with DG distribution network. It is not required that the strategy can solve all the problems of distribution network, but it must be able to solve most or most of the problems. Compared with the traditional protection strategy, this protection strategy is more suitable for the current distribution network environment. According to the idea of "adequate" protection, the characteristics of fault current in distribution network containing DG are studied in detail from the whole distribution network. The fault direction criterion based on negative sequence current amplitude and phase is used for asymmetric fault in distribution network, and the fault direction criterion based on positive sequence fault current amplitude and phase is used for symmetrical fault in distribution network. At the same time, the corresponding fault zone decision scheme is put forward. Then, in the determined fault area, the load current phase is taken as the reference, and the fault interval is accurately located by comparing the current phase after the fault at both ends of the line. This scheme can not only realize the accurate location of fault zone, but also reduce the traffic of distribution network to a certain extent. Finally, the scheme of distribution network protection based on "adequate" directional protection is summarized, and its structure and flow are analyzed in detail. The model of distribution network with DG is established on Matlab/Simulink platform, and its dynamic simulation is carried out. Combined with theoretical analysis and simulation, the conclusion shows that the scheme has a strong adaptability to different fault types of distribution network, and can quickly and accurately remove the distribution network faults.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM77

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