【作者】 高新智；

【导师】 李景禄；

【作者基本信息】 长沙理工大学 ， 高电压与绝缘技术， 2010， 硕士

【摘要】 水电站是一种经济性、环保性、可持续性都较好的发电厂,由于我国的河流众多,并且国内经济的高速发展对电力的需求量也越来越大,水电站的数量也在不停的增加,尤其是三峡等一大批大型水电站的相继建设,安全运行是水电站的基本要求,水电站的接地电阻值是保证水电站安全运行的重要系数,很多水电站建设完成后,就发现水电站的接地电阻超过了水电站安全运行的接地电阻值,然而大型水电站(包括常规水电站和抽水蓄能电站)一般都建在土壤电阻率较高的山区等地区,因此,为了确保电站的安全稳定运行,提高供电可靠性,必须对这种问题进行专门的研究,提出相应的解决方案,并配备了一套与之相适应的安全保护系统。水电站的接地系统是保证水电站安全可靠运行、保障运行人员和电气设备安全的重要措施。当电力系统发生接地工频短路故障或其它大电流入地时,如果接地电阻值比较大,就会造成地网电位升高;而且如果接地系统设计方案不合理,还会导致接地系统本身局部电位差超过安全值。可见,电力系统的接地问题是一个看似简单、实际上却是特别复杂而又至关重要的问题,它直接关系到人身安全及电力系统安全稳定的运行,有效抑制由入地电流引起的电压上升或跨步电压的产生。本文首先对影响水电站接地电阻大小的一些因素,其中有地形特点、水电站结构特点、水电站的环境因素进行了详细的分析。通过对光照水电站和锦江水电站进行现场调查和测试,并根据调查和测试结果对两个水电站进行了改造方案的设计。在对水电站的接地问题进行分析,从接地连接问题、均压问题、工频电阻超标、接地网的腐蚀问题几个方面进行了讨论,针对水电站存在的问题提出了针对性的、切实可行的改进措施,以保证水电站的安全稳定运行,并对其他水电站的综合改造起到参考作用。更多还原

【Abstract】 Hydropower station is economic, environmental, and substantial. Due to the large number of rivers in China as well as the growing demand of electricity, the number of hydropower stations is constantly increasing, especially the construction of Three Gorges and other large hydropower stations. Safe operation is the basic requirement of power station. The grounding resistance value is an important coefficient to ensure the safe operation of hydropower station. After the completion of constructing many hydropower station, the station’s grounding resistance value is found higher than the value needed by the safe operation of hydropower station However, large-scale hydropower stations (including conventional hydropower station and pumped storage power station) are generally built on high mountains where the soil resistivity is high, therefore, in order to ensure the safe operation of power stations, and improve power supply reliability, special research and appropriate solutions must be done, and a suitable security system must be equipped.Grounding system in hydropower station is an important measure to ensure safe and reliable operation, security of personnel, electrical equipment. When short-circuit fault happens or other high current comes into the ground, if the grounding resistance is quite high, it will cause a potential rise in net; and if the grounding system design is unreasonable, the local potential difference of grounding system itself can be higher than the safe level. It can be seen that power system grounding problem is a seemingly simple, but in fact particularly complex and vital issue. It is directly related to personal safety, security and stability of power system operation. It can also effectively inhibit the generation of voltage rising or step voltage .This article first analyzes the influential factors of grounding resistance in hydropower station in detail, such as terrain features, structural features and environmental features of hydropower station. According to the results of field investigation and testing in Guangzhao hydropower Station and Jinjiang hydropower Station, the design of modification scheme in these two hydropower stations are completed .Grounding in hydropower station is analyzed. Issues of Grounding connection, voltage, excessive frequency resistance, corrosion of grounding are discussed. Specific, practical improvement measures are proposed in terms of problems existing in hydropower station to ensure the safe operation of hydropower stations, and play the referential role in comprehensive transformation of other stations .更多还原