含分布式电源的配电网保护方案-电气工程;电力系统及其自动化专业论文.docxVIP

华北电力大学硕士学位论文 华北电力大学硕士学位论文 I I 摘 要 分布式电源(Distributed Generation,简称 DG)是一种新兴发电技术，具有高 效、环保的优点。然而，传统的单电源辐射网络因为 DG 的接入变为复杂的多电 源网络，导致原有保护出现一系列问题，如灵敏度降低，误动，拒动等，因此研 究新的保护方案对配电网是十分必要的，从而可以推广和发展 DG。 本文首先介绍了不同技术类型的 DG 的运行特点。由于接入配电网的小容量 DG 大多通过电力电子装置输出，因此需要分析逆变型 DG 的控制方式和对故障 的响应特性进行电源模型的等效，从而为研究逆变型 DG 对配电网保护系统的影 响奠定了基础。 定性分析了保护流过电流在多种情况下受到例如 DG 接入位置的变换，接入 容量的变化等的影响。针对现有的配网保护提出了改进方案，主要是加装方向元 件、修改定值或采用纵联差动保护。提出了含 DG 配电网保护的新方案：将上游 每条线路方向电流保护的 I、II 段与其下一级线路保护的 I、II 段构成一个通讯单 元，依据两级保护动作结果的综合判断将故障快速地隔离在最小范围内。建立基 于以上分析结论的算例模型，PSCAD/EMTDC 仿真结果验证了所提出的方案的 有效性。 关键词：分布式电源；配电网；电流保护 II II ABSTRACT Distributed Generation(DG) is an emerging technology, with high efficiency, environmental. However, with the interaction of DG, the traditional single-source radial-network has developed to the complicated multi-source loop-network, bringing traditional protection in a series of problems, such as sensitivity decrease, misoperation and malfunction, etc. Therefore it is necessary to research on the new scheme of protection for the distribution network, which can promote and develop the DG. The paper introduces the characteristics of different kinds of technology of DG. Because most small capacity DGs connected to the distribution network use electrical-electronic devices to supply the power, it is necessary to analyze the control scheme and the characteristics of fault respondence of DG to complete the equivalent model of DG. This model will be used for the analysis of the effects of DG on the protection system of the distribution network. In this paper, improvement schemes are proposed in this light of the existing distribution protection, mainly including installing the direction element，modifying the setting value and using the longitudinal differential protection．A new protection principle in distribution network is also proposed: the zone I，II relay of direction and current protection on every line composes a communication unit with the zone I，II relay of the next stage protection on the a