一种低压辅机低电压穿越装置的设计

Design of a Low-Voltage Ride Through Device of Low-Voltage Auxiliary Machine

近年来,并网火电机组在辅机设计上广泛应用变频器技术,一般不具备自动工频切换旁路,但在重负载下,"瞬停"功能并不适用,不能满足《发电厂及变电站辅机变频器高低电压穿越技术规范》的要求。外部故障造成的电压跌落,会导致变频器跳闸,进而可能引发机组跳闸事故。因此解决低压辅机低电压穿越问题变得极为重要。文章设计了一种低压辅机低电压装置,通过参数设计及闭环仿真试验,证明其解决了辅机变频器低电压穿越能力不足的问题。

In recent years,the inverter technology has been widely used in the design of auxiliary machine for grid-connected thermal power units.Generally,there is no automatic power frequency switching bypass.However,under heavy load,the"instantaneous stop"function is not applicable.At present,the resistance to voltage sags of the frequency converter dose not meet the requirements of Technical specification of high and low voltage ride through for inverter in power plant and substation.The voltage drop caused by external faults will lead to tripping of the frequency converter,or even cause the unit to trip.Therefore,it is very important to solve the low-voltage ride through of the low-voltage auxiliary machine.In this paper,a low-voltage device of low-voltage auxiliary machine is designed.Through parameter design and closed-loop simulation test,it is proved that it can solve the problem of insufficient low-voltage ride through ability of auxiliary machine frequency converter.