Our company's second-level booster water pump station has two 160 kW booster motors. They use a delta-yellow start-up method and operate continuously for extended periods. Operators manually adjust the shut-off valves based on pressure changes, but cannot adjust them in real-time. This results in significant energy waste. Based on this situation, we conducted an in-depth analysis of its load characteristics and, combined with the features of the Huawei TD2100 frequency converter, implemented a frequency conversion energy-saving retrofit. 1. Current Status and Technical Analysis Through observation and statistics, the motor current fluctuates between 200 and 284 A; this difference is caused by changes in flow rate. Analyzing its PQ characteristic curve and theoretical calculations, Figure 1 shows its PQ characteristic curve. The current changes between 100% and 70%, assuming the flow rate also changes between 100% and 70%. When the flow rate changes from 100% to 70%, for valve control, closing the valve causes the impedance curve to change from R1 to R2, and the operating point to shift from A to B; if speed control is used instead, the flow rate shifts from point A to point D on the same impedance curve R1. As can be seen from the change in shaft power, adjusting the speed can save approximately 30% of the energy compared to regulating the valve. [b]2 Functions and Hardware Configuration 2.1 System Composition Principle[/b] The system composition is shown in Figure 2 below: QF1 and QF2 are automatic switches. KM0-KM3 are contactors, and FR1 is an overheat relay. TD2100 is a Huawei water pump dedicated frequency converter. Under normal conditions, QF1 is closed, TD2100, KM0, and KM2 operate, and the water pump performs frequency conversion speed regulation to achieve energy-saving control; in the event of a device failure, QF2 is closed, and the Δ-Y starting circuit composed of KM1, FR1, KM2, and KM3 operates at the power frequency. This ensures the normal operation of the system. 2.2 Functions and Features of Huawei TD2100 Frequency Converter This renovation uses the Huawei TD2100 frequency converter, which integrates water supply control and water supply management. It has a built-in dedicated PI regulator. Therefore, only one pressure sensor is needed to form a closed-loop water supply control system. The operation panel allows for operation of the frequency converter, setting of function parameters, and status monitoring. It also displays function codes and their parameters. The TD2100 offers eight water supply modes, enabling cyclic switching of four pumps and automatic switching between frequency converter and mains frequency. It can achieve PI closed-loop control. In this upgrade, closed-loop control was used, with pressure setting via a potentiometer and pressure feedback via a pressure transmitter to achieve constant pressure control. 3. Conclusion By using the TD2100 frequency converter, various control functions can be set, acceleration and deceleration times can be set, reducing start-up impact; in case of failure, the system reliability is effectively ensured through mains frequency/frequency converter switching. Due to its advantages of low investment, significant energy savings, and short investment payback period, this solution has been adopted by the company. [b][align=center]For more details, please click: Application of Frequency Converters in Energy-Saving Technology for Water Pump Control[/align][/b]