每相7分支水电与抽水蓄能机组主保护设计研究

Research on Main Protection Design of 7 Branches per Phase Hydropower and Pumped Storage Units

近年来,随着机组额定容量的增大并受额定转速的限制,一批水电与抽蓄机组采用每相7分支(9分支甚至11分支),有必要对每相7分支发电机的内部故障特点及主保护设计规律进行归纳总结——对于波绕组每相7分支的发电机,优先推荐"3-1-3"分支分组方式,立足于不完全裂相横差保护的使用;而对于叠绕组每相7分支的发电机,则优先推荐"3-4"分支分组方式,保留完全纵差保护的使用。并指出对于额定转速428.6r/min的抽蓄机组(14极/每相7分支)应推荐采用不对称定子绕组(改为每相4分支),既改善了发电机中性点侧铜环和分支TA的安装条件,又简化了发电机主保护的设计。上述研究工作将为后续大型常规水电站与抽水蓄能电站的建设提供借鉴。

With the increase in rated capacity of generator units and the limit of rated speed over the last few years,some generators and motor-generators have to adopt 7 branches,9 branches or even11 branches per phase,which make it necessary to summarize the internal fault characteristics and main protection design rules of7 branches per phase hydro-generator.For 7 branches per phase generators with wave windings,the＂3-1-3＂branch grouping method is recommended,which is based on the use of incomplete splitphase transverse differential protection.For 7 branches per phase generators with lap windings,the＂3-4＂branch grouping method is recommended,so the complete longitudinal differential protection is reserved.And for the pumped storage units with rated speed of428.6r/min（14 poles/7 branches per phase）,it is recommended to use asymmetric stator windings（replace with 4 branches per phase）,which not only improves the installation conditions of the generator neutral side copper ring and the branch TA,but also simplifies the design of the generator main protection.The above research work will provide reference for the construction of large conventional hydropower stations and pumped-storage power stations.