摘要
针对主变用电流互感器(CT)二次电流的减小,根据现场实际电流数据,判断出是由于CT一次接线压接错误形成一次附加回路造成的。应用电磁场理论详细分析了CT二次电流减小的根本原因,并根据变压器负荷,计算出在此附加回路影响下的主变保护差动回路电流,通过分析得到RCS-978稳态比率差动保护潜在误动的可能性。提出了更换CT时应注意变比与引线压接螺栓的对应关系、控制字与抬高差动启动门槛相配合的方案以避免保护误动,从而提高了主变保护的可靠性。
Aiming at decrease of main transformer CT（current transformer） secondary current, wrong connection leading to additional circuit is concluded according to practical current data. Prime cause of secondary current＇ decrease is analysed in detail applying electromagnetic theory. Protection＇s differential circuit affected by additional circuit is calculated according to transformer＇s load status. In conclusion, potential fault trip exists in RCS-978 stable ratio differential protection. Measures are brought forward to avoid fault trip, which should pay attention to corresponding between transformer radio and outlet impacted bolt when replacing CT, cooperation between control string and raising up differential protection＇s startup threshold, so that reliability of transformer protection is improved.
出处
《继电器》
CSCD
北大核心
2008年第7期83-85,共3页
Relay
