发电厂保护整定计算中的问题研究

【作者】 曾平；

【导师】 徐习东；

【作者基本信息】 浙江大学 ， 电力系统及其自动化， 2006， 硕士

【摘要】 发电厂主设备保护的种类繁多,随着新保护装置的不断推出,已有的保护整定规程不能直接地运用到有些新保护装置整定中;此外有些新保护装置虽然推荐了一些针对性的整定步骤,但也不够严密。围绕上述问题,本文对发电厂中一些主设备保护的整定计算进行了研究,尤其对变压器差动保护中平衡系数对差动门槛的整定影响的问题进行了比对。 首先研究了发电厂主设备的主保护的原理和整定计算方法,包括发电机、变压器、发电机变压器组、电动机等主设备。 其次发电机的主保护主要介绍了比率制动式纵差保护、不完全纵差保护、故障分量负序方向微机保护、多分支分布中性点水轮发电机的综合差动保护、单元件横差保护、纵向零序过电压保护、转子回路二次谐波电流保护等。 变压器的保护整定计算中,本论文着重对变压器差动保护中平衡系数对差动门槛的整定影响进行了研究。在平衡系数整定中,基本侧选择不同,将直接影响差动保护最小动作电流(差动门槛)的整定。本文探讨了目前存在的四种基本侧选择方式,并提出了差动门槛整定与基本侧的对应关系,以便更合理地整定不同保护装置的差动门槛。更多还原

【Abstract】 With the new protection equipments unceasing applying to power system, the original guide of calculating settings of relay protection for large generator and transformer can’t be directly acted on the settings of these new equipments.About the problem, this paper focuses on the setting of main equipment protection, especially on the influence of the coefficient of balance to the setting of the differential current threshold in differential protection for transformers.My researches are mainly on the pringciple and setting methods of electric power equipment protection, including Generator Protection, Transformer Protection, Protection of Generator-Transformer Unit and Motor Protection.About Generator Protection, we introduce longitudinal differential protection principle using percentage restraint, Single element transverse differential protection for turn-to-turn faults, Longitudinal zero sequence voltage (3Uo) protection for stator turn-to-turn faults, Split phase transverse differential protection for turn-to-turn faults and so on.My researches on Transformer Protection setting focuse on the influence of the coefficient of balance to the setting of the differential current threshold in differential protection for the differential protection for transformers.Instead of the balance windings for the traditional relays protection, digital transformer relay protection chooses the coefficient of balance. For the setting of the coefficient of balance, different choices of the reference windings will directly affect the setting of the differential current threshold. This paper reviews the current four basic ways for choosing the reference windings and comes up with the relation of setting of the differential current threshold and the reference windings. The purpose is to come up with the more reasonable setting of the differential current threshold for the different relays protection equipments.更多还原