摘要
大型发电机应装设动作电压 ≥5V的基波零序电压 (3U0 )定子单相接地保护 ,但实际运行中 ,6kV厂用系统单相接地时 ,发电机侧基波零序电压高达 13.2V和 11.9V ,造成发电机单相接地保护误动。误动原因是没有考虑高压厂用变压器耦合电容的传递零序电压。应该通过计算传递电压的大小 ,确定发电机 3U0 定子接地保护的动作电压值 ;或者为了获得动作死区 ≤5 %的 3U0 定子接地保护 ,增设厂用系统零序制动电压。
The large-sized generator ought to install the ground fault protection based on the zero-sequence fundamental voltage (3U 0)with the setting value not less than 5 V.But in the field operations,The 6 kV station service electrical system took place single-phase-to-ground faults reaulted in the zero-sequence fundamental voltages of generator reaching to 13.2 V and 11.9 V respectively,and the stator ground protection maloperated.Its reason lies in the zero-sequence transferring voltage caused by the coupling capacitance between primary and secondary windings of high voltage station transformer,which was not considered.The value of operating voltage 3U 0 should be set by calculation according to the transformer voltage,or the 3U 0 ground fault protection should extend the zero-sequence voltage of the station service electrical system as the restraint quantity for obtaining the operating dead-zone not more than 5%.
出处
《电力自动化设备》
EI
CSCD
北大核心
2001年第9期1-3,共3页
Electric Power Automation Equipment
关键词
变压器
低压侧单相接地保护
发电机
高压厂
ground fault protection
transferring voltage
zero-sequence fundamental voltage
