Application Of High Voltage Variable-frequency Technology In Panzhihua Iron And Steel Group High Power Fan

With the gradual reduction of profit level of China's iron and steel enterprises,improving product quality and reducing product costs have become the key factors for the survival of iron and steel enterprises,energy saving and emission reduction has become an important means of reducing production costs of iron and steel enterprises.Therefore,in iron and steel enterprises,the energy saving of the motor system is imperative.For the energy-saving of motor system,variable-frequency technology is the most ideal way to save energy,whether in speed regulation,starting performance or braking performance.The blower high-voltage motor of the profile mill line of Panzhihua Iron and Steel Co.Ltd.which provides heat treatment air source is started by soft start and depressurization,and the air volume is adjusted by adjusting the opening of the damper baffle.A considerable part of its energy is wasted on the loss of wind pressure,disturbance of the damper throttling medium and the throttling of the damper,which increases the production cost.In order to solve the problem of energy consumption of the high-voltage motor,the high-voltage variable-frequency control is adopted.The system replaces the original high-voltage soft start system,which has the characteristics of low cost,simple implementation and wide application range.Firstly,after analyzing the structure,control principle and advantages and disadvantages of various high voltage converters,according to field investigation,it is determined to replace the original high voltage soft starter with HARSVERT-A high voltage unit series multi-level PWM voltage source converter;secondly,the calculation and selection of phase-shifting transformer and power unit components,and the principle and reality of frequency converter control system are expounded.At present,the data interaction between the frequency converter control system and the basic automation control system and the choice of the cooling mode of the frequency converter;at the same time,in order to realize the local start-up and motor protection function of the high-voltage converter,Siemens S7-300 series PLC is used as the control core,and the design and programming of the auxiliary control system PLC of the blower high-voltage motor are elaborated;finally,the power saving rate,investment cost and start-up are discussed.The implementation effect of the project is analyzed from multiple perspectives,such as the success rate of the project.This topic uses high voltage variable-frequency converter converter and speed sensorless vector control technology to make the AC motor close to the starting moment of the same power DC motor,solve the problem of starting difficulty,eliminate the influence of motor starting on power supply grid,and raise the success rate of starting from about 70% of the original system to 100%.The monthly electricity saving rate can reach about 32%,which can save 1.83 million yuan per year for Panzhihua Iron and Steel Profile Plant,greatly reducing the energy consumption of motor.In addition,through variable-frequency regulation,the impact of mechanical equipment is reduced,the service life of equipment is prolonged,and the maintenance cost is saved.