Analysis of the Efficiency of Using Cascade-Frequency Control of a Group of Feed Pumps at an Industrial Power Plant

The paper considers the issue of increasing the energy efficiency of factory power plants. A review of the literature was carried out, in which Russian scientific works are presented. It was revealed that one of the main factors that reduce the energy efficiency of power plants is the consumption of electricity for own needs. In order to reduce the consumption of electricity by own needs, it is proposed to use the principle of cascade-frequency regulation to control a group of pumps. The feed pumps of the factory power plant with feed water cross-links were chosen as the object of study. An example of the operation of four feed pumps for a common collector with the condition of maintaining the required water flow at a given network pressure is considered. Instead of traditional throttling, it is proposed to control the performance of pumps by changing the speed of rotation of the drive. This reduces the consumption of electrical energy. A distinctive feature of the proposed control scheme is that some of the pumps required to maintain a given feed water flow rate are connected to one frequency converter. Regulation takes place at the same speed. A block diagram for selecting the optimal operating mode for a group of pumps of the same type has been developed. For a given network characteristic, various options for connecting pumps through frequency converters were obtained. The expediency of operation of a group of pumps with different frequency and load when working on a common network is considered. Recommendations have been developed for the use of frequency-controlled noses, taking into account the minimum costs for a given performance.