Abstract : This paper introduces the specific control scheme and implementation process of motor frequency conversion modification based on the renovation of the heat network drainage system of Shangwan Thermal Power Plant. Keywords : frequency converter; water pump; target signal; feedback signal [b]1 Overview[/b] Fans and water pumps are used extensively and frequently in power plants, and most of the plant's electricity consumption is consumed in the operation of various motors. In production, due to changes in operating conditions, the output of various motors should also change. However, the output of motors can generally only be controlled by adjusting the opening of valves and baffles to control the water and air volume. How to save energy and reduce consumption, reduce plant electricity consumption, and improve operating economy is an urgent issue. The motor frequency conversion technology of developed countries provides us with experience that can be learned from. The installation and modification of frequency converters have three major advantages: safety, energy saving, and environmental protection, and have excellent energy-saving effect. In 2006, Shangwan Thermal Power Plant renovated the drainage system of the heating network and used frequency converter pumps to regulate the drainage flow of the system, which achieved significant results. 2. System Principles, Modification, and Operation The Shangwan Thermal Power Plant heating system consists of heating network heaters #1 and #2, water-to-water heat exchangers #1 and #2, circulating water pumps for the heating network #1, #2, and #3, a heating network deaerator, and the heating pipeline network, as shown in Figure 1. [b][align=center]For more details, please click: Application of Frequency Converters in Power Plant Drainage Systems[/align][/b]