Change And Analysis About Consensate Pump Frequency Conversion Of A 1000 MW Supercritical Power Unit In Shanghai-Caojing Power Generation Co.,Ltd

The total designed capacity of the two generator sets at ShanghaiCaojing Power Generation is 2000 MW.According to the condensation return system design,each generator set is equipped with three condensation return pumps with each pump designed to handle 50% of condensation return requirement.During normal operation,two of the three condensation return pumps are in lead position,leaving one pump in lag position.It is noticed from actual operations that while the generator sets are operating under normal or low loads,condensation return pumps tend to fall into low efficiency regions.Also condensation return pumps utilize traditional regulative valves to control the deaerator water level,resulting in high power consumption and unwanted vibrations in the system.Those regulator valves are also susceptible to wearing.On the other hand,starting current of the condensation pumps is considerably high,which poses stress to the plant’s power and mechanical systems and increases their maintenance costs.The above factors can also be potential safety hazards that may interfere the normal and safe operation of the generator sets.Using variable frequency controls on condensation return pumps can effectively increase working efficiency,operation stability and safety of the condensation return system.In order to improve operation condition of the pumps,to lower power consumption,and to increase efficiency of the generator sets,condensation return pumps of #1 and # 2 generator sets are subject to be controlled by variable frequency.Based on the actual condition at Shanghai Electric Power Caojing Power,this article analyzes the composition equipment of the condensation return system and its energy saving principle.Through introducing the working principle of high voltage variable frequency drives and controlling mechanism of alternating current governor system,the article justifies the equipment selection for the detailed transformation plan.The articles also provides power saving and operation effect analysis for the application of the variable frequency technology.It is concluded that the variable frequency technology exhibits great energy saving effect,lowers the maintenance frequency of the system,and prolongs the equipment’s life span.Therefore,variable frequency technology is worth to be applied to a larger extent.