【摘要】 自耦变压器的分差(零差)保护原理上不受励磁涌流影响,但是国产330kV三相一体自耦变压器在空充时分差(零差)保护时有误动。通过对多起保护误动分析发现,误动原因不是保护原理问题,而是公共绕组电流互感器(TA)传变异常。比较国产和合资的自耦变压器空充电流波形数据,发现其原因并非公共绕组TA特性和饱和等问题,通过对主变内部结构分析得出,国产变压器内部公共绕组TA没有考虑防止主变空充时漏磁通对公共绕组TA的影响。提出了防止保护误动的改进措施,建议国产主变制造厂家研究改进三相一体自耦变压器内部结构,从根本上解决公共绕组TA传变异常问题。更多还原

【Abstract】 The phase segregated(zero sequence)differential relay for auto-transformer is principally not affected by transformer magnetic inrush.However the relay mal-operations happened occasionally on domestic made three phase compact auto-transformers during their no load energizing.The causes of relay mal-operation are found to be abnormal transformation of common winding current transformer other than the relay operation principle itself after several cases studied.Furthermore,based on the comparison of the energizing current shape data between domestic made transformer and joint venture made ones,it is concluded the characteristics and saturation of common winding current transformer are not problems.With structure analysis of auto-transformer,it shows that the influence of leak flux rising from transformer energizing on common winding current transformer is not considered in domestic made auto-transformers.Therefore improvement measures for relay operation criteria are put forward on the basis of analyzing results.Finally it suggests that transformer manufacturers study and improve the transformer internal structure in order to completely solve the abnormal transformation of common winding current transformer.更多还原