Overvoltage mitigation of submersible motors with long cables of different lengths

As we know, submersible motor which works underground is powered by long cable. This will lead to a series of problems, such as overvoltage and high-frequency oscillation damping. To facilitate the effective suppression of motor terminal overvoltage, transmission line theory and distributed parameter thought are adopted into the motor terminal voltage analysis. Based on submersible motor system modeling, a specific function of factors that affect motor terminal overvoltage including cable length, PWM pulse rising time and terminal reflection coefficient is given and verified by simulation. Moreover, this article puts forward a novel method of designing LR parallel filter, which only needs the natural oscillation frequency of long cable without complex design steps. Simulation results show that passive filter design method used in this paper is simple and restrains terminal overvoltage within 20%.