摘要:本次设计任务旨在体现对本专业各科知识的掌握程度,同时检验本专业的学习成果。首先,根据毕业设计的要求,建立合理的电力系统,本次毕业设计以拟建10KV供电系统为例。其次,根据毕业设计的主要内容,对10KV电力系统进行继电保护配置,并依据继电保护配置原理,对所选择的保护进行整定和灵敏性校验,确定保护方案。
本次毕业设计分为五个章节,第一章某镇10KV供电系统分析主要是对负荷的分析,再选择主变压器台数、容量、绕组的连接方式,最后是电气主接线的确定;第二章是系统短路电流的计算,包括短路电流的概念、种类,短路电流计算的目的,以及短路电流标幺值计算法;第三章线路保护,包括线路保护原理分析、保护整定计算和灵敏性校验,继电保护的作用,继电保护的基本要求,继电保护的基本原理,本系统采用双电源网络相间短路的电流保护,包括电流速断保护,定时限过电流保护,过电流保护;第四章变压器保护,主保护采用的是纵联差动保护、过负荷和瓦斯保护,后备保护是过电流保护,保护整定计算和灵敏性校验。第五章防雷保护,根据变电站示意图情况下采用两根等高避雷针进行防护设计并计算其保护范围使其对变电站进行保护。
关键词:短路电流;整定计算;灵敏度;继电保护
Abstract:This design task aims to reflect on the professional subjects knowledge, at the same time test the professional learning outcomes. First of all, according to the requirements of graduate design, establish a rational power system, the graduation design with the10KV power supply system for example; secondly, according to the graduation design of the main contents, the10KV electric power system relay protection configuration, and on the basis of relay protection configuration principle, the choice of protection setting and sensitivity calibration, identification protection scheme.
This graduation design is divided into five chapters, the first chapter of a town of10KV power supply system analysis is mainly on the analysis of load, the main transformer number, capacity, winding connection mode, finally the main electrical wiring; second chapter is the system short circuit current calculation of short-circuit current, including the concept, types, short-circuit current for computational purposes, as well as the short-circuit current per-unit value calculation method; third chapter line protection, including line protection principle analysis, protection setting calculation and sensitivity calibration, relay protection, relay protection of the basic requirements, the basic principle of relay protection, this system uses the single power supply network of interphase short circuit current protection, including current quick break protection, timing and limiting current protection, simple and practical; the fourth chapter transformer protection, including the transformer protection principle analysis, protection setting calculation and sensitivity calibration, main protection is longitudinal differential protection and gas protection, combining the two achieve an advantage complementary, backup protection is of over current protection. The fifth chapter lightning protection, according to the main wiring diagram, lightning parameters in the case of two high lightning protection design and calculation of its scope of protection on the lines for protection.
Key words: short circuit current; setting calculation of relay protection; sensitivity.