Estudo da partida de motor de indução de grande porte em ambiente de rede elétrica fraca

Abstract

This work presents a case study of starting a 600 HP three-phase induction motor employed to drive a vertical turbine pump that is used to take underground water in a deep well. The load shows high inertia and high breakaway torque. The grid provide a low short circuit capacity and how is the case a high voltage drop during the starting, given low level voltage at motor's terminals. Those aspects make unworkable the direct on line starting and other kind of convetional starting techniques. The analysis of diferent options indicates the use of variable frequency drive to a proper starting. The mathematical modeling considerates all of system's electric elements. The induction motor is represented by dq model. The results are presented by a computational simulation that prove how feasible is the solution. Employing the variable frequency drive and the vector control technique the limitation imposed by the weak grid do not afect the motor starting making this kind of drive the more suitable solution for the case study and therefore adopt for the practical aplication.