Comparative Study between Medium and Low Voltage Motors for Water Stations

An IM (induction motor) usually draws a high starting current, about eight times its rated current, when it is connected to the grid DOL (Direct on Line). The starting current is proportional to the applied stator voltage. Starting the motor with a voltage higher than its rated value results in a high starting torque. If this starting torque is very high and applied for an extended period, it may cause a mechanical jerk. The operation of both LV (low-voltage) and MV (medium-voltage) motors is similar regardless of the cost of their corresponding infrastructure and additional starting equipment. This paper studies an installed water station including both LV and MV induction motors. The study aims to discuss and analyze the effects of replacing either LV or MV motors with each other. So, three different scenarios of replacing the motors according to their operating voltages are introduced and simulated using ETAP power station software to discuss the power quality and corresponding cost of the water station. The best choice for operating the water station will be investigated. In the first scenario, representing the current state of the water station, there are three LV motors and one MV motor. The second is a proposed scenario, which involves replacing the MV motor with two LV motors, ensuring proper constraints for load requirements. The third scenario is also proposed and involves replacing the three LV motors with a single MV motor. The simulation results showed that MV motors were more efficient in terms of power quality, and the economic study also showed that MV motors are cheaper in initial and running costs.