摘要
本文在标幺制算法基础上对某变电所10Kv出线相间短路引起的变压器保护误动作进行了分析。查明了事故原因,建立了故障模型,提出了具体的防范措施。由于某出线出口处发生永久性相间短路,作为其相间故障主保护的过流Ⅰ段动作将921断路器跳闸,这一故障的永久性导致了线路重合闸的失败;经排查发现,将变压器高压侧计量用的电流互感器与差动保护用电流互感器接反,致使这一侧的电流互感器在外部出线侧短路电流流过时迅速饱和,在差动回路产生很大的差电流,导致采样出错,发生差动保护误动作,致使这一主变误跳闸。
This paper mainly analyzes the mal -operation of the main transformer caused by the 10KV phase short -circuit in the given power substation based the Per - Unit System. The fault analysis model is established. The precautionary measurement is pro- posed by finding the accident reasons. Because of the permanent phase fault at the head of the line, instantaneous over - current pro- tection （Segment I ） as its main protection of the phase fault made the 921 breaker trip and the permanence of his fault let to the fail- ure of the reclosing. Investigation dedicates that reversed the TA（current transformer） for measuring with the TA for differential pro- tection in high voltage side of the transformer, this fault can also make the TA of the differential protection circuit quickly saturated when the external short - circuit current flowing through the TA. When the above saturation happens, a big differential current gener- ating from differential circuit will lead to sampling error. This is the direct cause of the mal - operation of the differential protection which resulting in the 2nd transformer tripping.
出处
《内蒙古农业大学学报（自然科学版）》
CAS
北大核心
2014年第5期114-117,共4页
Journal of Inner Mongolia Agricultural University(Natural Science Edition)
基金
内蒙古自然科学基金项目(2012MS0732)
关键词
标幺制
变压器
电流互感器接线
继电保护
电磁暂态分析
Per - Unit system, transformer current transfer former relay protection, electromagnetic transient analysis
