发电机中性点接地方式分析选择

【作者】 朱杰民；

【导师】 沈成能； 牛巨山；

【作者基本信息】 大连理工大学 ， 水利工程， 2002， 硕士

【摘要】 通过各种接地方式的分析，介绍了发电机中性点接地的概念，了解了各种接地方式的主要优缺点。针对大中型发电机的两种主要接地方式进行了分析，进行了接地故障电流、三次谐波保护的计算推导，首次在接地变高阻接地方式有关公式推导中计入接地变感抗，从而使人们对接地变高阻接地认识更为全面。在暂态过电压和三次谐波保护等问题上，提出了一些不同观点。从而为工程设计和生产制造有关人员提供了有益的参考和比较。 由于暂态过电压、接地故障电流等都直接与发电机接地方式有关，同时还影响或决定着发电机的保护形式，所以接地方式的选择在理论和实践上都是一个复杂的问题。 在现有大中型发电机中性点接地选择上，主要有消弧线圈接地方式和接地变高阻接地方式。经分析比较认为，在水电站水轮发电机组宜选用接地变高阻接地方式；在火电厂和热电厂汽轮发电机组，选用何种接地方式，给出明确的结论尚需理论和实践的进一步深入。更多还原

【Abstract】 Through analyzing of every kinds of generator ground,introduces the concept and there have knowing of all kinds of generator grounding. Have studied generator ground model mostly used in detail for middle and big domestic generator units.Calculates and deduces fault current as grounding of single phase and third harmonic fault protection schemes. First time contributes overall knowledge about generator neutral grounding of distribution transformer with secondary resistor,in which considered inductance of the transformer to people. Brings out some new and different viewpoint on issues of transient and dynamic voltages for generator single phase fault as well as third harmonic fault protection.! Presents good references for engineering design and manufacture person who deal with the generator neutral ground.Because there is direct relation ship with fault currents and transient and dynamic voltages,in theory or practice,it is so complicated that the selection of generator neutral grounding model will affect or determine the generator protection scheme.In mode selection of middle and large capacity units nowadays,there mainly have two types of Peterson coil grounding and distribution transformer with resistor. By analyses and compares,the conclusion is that it would be better to choose high resistance grounding of distribution transformer for hydro turbine in hydro power station. There is no certain conclusion for steam turbine in fossil-fired power plant. Getting a clear answer to choose good generator grounding mode still needs practice and time.更多还原