Estudo de um sistema integrado de bombeio centrífugo submerso

Abstract

This work shows studies, modelling and analyses of an electrical submersible pump system (ESP), considering the characteristics of key elements in this system. The contributions are in its start-up, as also in the development of solutions for mitigation of some observed problems, e.g., those related to power quality at the equipment terminals. The model for each electrical equipment inside the ESP is presented in this work and highlighted some of the pertinent operational aspects that is commonly considered on practical operation. A project is settled for sizing the passive filters to attenuate the harmonic components of the voltages and currents supplied by the grid, in addition to helping voltage regulation at ESP connection point. In the study cases, it was considered a medium voltage power system with a 3835HP three phase squirrel cage induction motor which is connected with a centrifugal pump that results in a high inertia coefficient. Rotational friction model is considered in the studies to characterize the effects that occur at the initial seconds of the start-up of the system and also to evaluate the performance of the implemented control strategy. In the same way that occurs in real systems that are supplied by downhole electric cables, it was considered an open-loop V/f control with a methodology to estimate and compensate the voltage drop that exists between the terminals of the converter and the motor input. This work also establishes a short comparison between a 2-level voltage source converter (VSC) and a 3-level neutral-point clamped (NPC) VSC. Finally, the system is analyzed through the occurrence of an unbalance of downhole electric cable parameters.