Energy-saving Retrofit And Operation Test Of Variable Pole Speed Regulation Of Circulating Water Pump Motor In Thermal Power Plant

Circulating water pump is one of the important equipments of thermal power plants.In the northeastern region or thermal power plants with large seasonal temperature difference,the efficiency of circulating water pump is wasted.The speed regulation of circulating water pump has certain energy-saving potential.This paper expounds five kinds of speed control methods,such as frequency conversion speed regulation and variable pole speed regulation of electric motor,and compares and analyzes the characteristics of these five speed control modes.Combined with the working principle and characteristics of vertical diagonal flow pump,The research focuses on the variable pole speed regulation mode of the motor.The characteristics of three common two-speed motor control methods,namely,three circuit breakers,single circuit breaker plus local switching box and single circuit breaker control mode are compared and analyzed.At the same time,combined with the high and low speed transformation project of circulating water pump motor of Datang Changchun Third Thermal Power Plant,the necessity of using variable pole speed regulation method for circulating water pump motor was analyzed.After analysis and comparison,the control mode of single circuit breaker was selected and combined with pipeline The characteristic curve and the performance curve of the pump determine the number and speed of the two-speed motor transformation and design the stator coil of the motor.The process of motor pole transformation is introduced in detail,and the motor is in the process of pole transformation.Due to the change of winding wiring mode,the causes of motor electromagnetic noise are analyzed,corresponding control measures are formulated,and single circuit breaker is adopted.In the control mode,the research has established effective measures to prevent the phenomenon of overheating and sparking in the newly added outlet box of the motor.At the same time,the precautions for the modification of the variable speed of the motor are explained.The setting values of the high and low speed protection of the circulating water pump motor after the transformation were calculated.Through the on-site operation test,the test data reached the qualified standard,and the energy-saving calculation analysis was carried out to demonstrate the circulating water pump of Datang Changchun No.3 Thermal Power Plant.The variable-speed speed control system of the motor is stable and reliable,and can achieve the expected effect of energy saving.