Abstract : Energy saving and consumption reduction is only one of the purposes of using medium-voltage frequency converters in water plants. Constant pressure water supply and improving the automation control level of water plants are equally important. As the main water plant in Taicang area, the water plant pumping station is an important production position in the plant. There are 4 medium-voltage 6kV water pumps, which are responsible for the water supply for the production and domestic water of the vast number of users. Therefore, the operation status of this device is directly related to whether the entire water plant can operate normally and safely. Status before the renovation The four water pumps in the water intake pumping station send the Yangtze River water introduced from the suction well through the gravity pipe to the water supply workshop. After being treated by processes such as reaction, sedimentation, filtration and disinfection, it is sent to the clear water pool, and then the water supply pumping station supplies water to users. In the years of operation, the following problems have been found to restrict the safe operation of production: (1) The water consumption of users varies with the season, with the workday and rest day, and with the difference between day and night. In addition, the water consumption of different users varies with peak and off-peak periods, making it difficult to control the water supply and demand. Furthermore, the entire water supply system has a large design margin to meet the maximum water supply requirements, resulting in a significant waste of electrical energy during low-load periods. (2) Operators need to frequently increase or decrease the number of pumps in operation or adjust valves to maintain water balance, greatly increasing their workload. Moreover, this method makes it difficult to ensure constant water pressure, which fluctuates within a certain range, affecting water quality. (3) Frequent pump starts increase the mechanical impact on the motor and pump, shortening their maintenance cycle and service life, increasing equipment maintenance costs. Voltage fluctuations during the start-up of large-capacity pumps have adverse effects on other operating equipment. [b][align=center]For more details, please click: Variable Frequency Control System of Taicang Water Plant[/align][/b]