长距离电缆线路电容电流解决方案

Solutions to Long Distance Cabling Capacitance Current

针对伊朗某油田项目KUS和HOS两接转站正常运行时11 kV母线电压偏高、故障时工频过电压过高、两接转站下属的井口负荷电缆出现单相接地故障时造成燃气发电机组停机的实际问题,计算11 kV电缆线路接地电容和电缆充电功率,确定了在两接转站的电缆首端分别加装1 000 kVA隔离变压器及在两个接转站11 kV母线上分别加装800 kvar和1 300 kvar并联电抗器的解决方案。仿真结果显示,该方案可以有效地降低两接转站正常运行时的母线电压及故障时的工频过电压,同时综合保护定值可以合理整定,避免了井口故障电流冲击燃气发电机组造成的频繁停机。

In an oilfield project in Iran, actual problems exist in KUS dnd HOS OGM, namely the 11 kV bus bar over-voltage during normal operation, the power frequency over-voltage in a failure and the gas generator set shut down caused by single phase grounding failure of load cables at the well- head belong to the two OGMs. In view of above problems, ground capacitance and cable charging power of 11 kV cables are calculated, and then the solution that installing isolation transformers with 1 000 kVA at the head end of power supply cables and shunt reactors with 800 kvar and 1300 kvar on the 11 kV bus bar of HOS and KUS OGM respectively is determined. Thesimulation result shows that the solution can effectively reduce the bus voltage of the two OGMs during normal operation and power frequency over voltage in a failure, properly set comprehensive protecting constant values and avoid frequent shut clown of the gas generator set caused by failure current surge at the wellhead.