水下大功率电机远距离变频驱动过电压问题分析

Analysis of the Over-voltage Problems of Variable Frequency Drives Long Distance Subsea High Power Motor System

随着深水油气资源的开发,水下电潜泵、增压泵、压缩机等大功率电机变频驱动的应用越来越多,也带来了诸多应用问题,变频器高频分量引起电机端过电压便是其中一个重要问题。本文通过仿真计算,分析了经不同距离海底电缆变频驱动水下大功率电机的过电压特性,得出了海底电缆和电机端过电压在不同载波频率(50~4000 Hz)、不同距离(1~30 km)的特征规律。研究结果表明,短距离(几公里)变频驱动更有可能出现较高的过电压。针对电抗及LC两种滤波方式进行的对比分析,提出了抑制水下大功率电机变频驱动过电压的推荐措施,以及海底电缆和输出滤波器的选取建议。

As the deep water oil and gas field development,there are more and more applications of subsea Electric Submersible Pump(ESP),boost pump and compressor driven by Variable Frequency Device(VFD).Meanwhile some problems are brought by the VFD drive system,over voltage of the motor terminal caused by VFD high frequency harmonic is one of the important problem.In this paper,over voltage character of VFD drive subsea motor through different distance submarine cable was analyzed by simulation,and present the over voltage character of different distance(1~30 km)submarine cable terminal which connected the motor under different control carrier frequency(50~4000 Hz).Study show that short distance(several kilometer)VFD drive system is more likely have higher over voltage.Bothe reactor and LC filter also been analyzed and compared in this paper.The over voltage restriction method,submarine cable selection and filter selection suggestion has been proposed.