Comparison and economic analysis of starting processes of asynchronous motors used in raw water pump in drinking water treatment plant

With the increase in energy consumption and costs in the world, saving measures have begun to be taken, and some improvements on the operating system have enabled energy to be used more efficiently. The issue of how to reduce the amount of electricity consumed by electric motors designed on currently operating systems, according to their capacities, has been brought to the agenda. In this process, savings in electricity consumption were achieved through improvements made in the energy classes and starting systems of asynchronous motors, which consume the most electricity. In order to ensure the natural flow of water from the point where the treatment facilities are located to the tanks within the city, it needs to be installed on a certain level. According to the topographic structure of the cities, the fact that the raw water collection level of the dam level is lower than the elevation where the treatment plant construction is located prevents the raw water from reaching the treatment plant. At this stage, pumping is required to deliver the raw water released from the water intake structure in the dam to the treatment plant. Asynchronous motors are generally used for pumping. In this study, the facility of currently operating ring asynchronous motors, which allows the raw water released from the Gökçe Dam, which provides Yalova drinking water, to reach the treatment plant, was evaluated. In this facility, there are 6 groups and a total of 14 pumps operating at various powers depending on the level in the dam. It was evaluated to use IE4 efficient asynchronous motor instead of one slip-ring asynchronous motor from each group and to provide the starting system with driver panels. The speed of the motors was controlled by adjusting the required flow rate via frequency. The use of IE4 efficiency (93.8%) AEMOT brand asynchronous motor in the system was evaluated. In the evaluation based on the operating conditions, it was observed that the IE4 asynchronous motor with inverter consumed 2.21% less electricity per hour compared to the currently operating slip-ring asynchronous motor with rectifier. Considering that the motors are operated for 8 hours per day, the annual energy saving of the IE4 asynchronous motor with inverter is determined to be 20,736 kWh. In addition, it has been evaluated that providing speed control with frequency instead of valve throttling required by the use of slip-ring asynchronous motors will increase energy savings.