热电厂给煤机低电压穿越改造技术研究

Research on Low Voltage Ride Through Technology of Coal Feeder in Thermal Power Plant

电网电压短时跌落会造成厂用电压降低,触发变频器的低压保护,使变频器闭锁输出,最终导致非停事故。为保证机组安全稳定运行,热电厂为给煤机变频器各加装一套抗低电压穿越装置。本文分析了变频器低电压穿越治理原理,比较三种低电压穿越改造方案的性能,根据现场特点选用了"厂用直流220V+隔离功率模块"方案,最后对该方案进行试验验证。

When the grid voltage drops for a short time,the factory voltage will be reduced.Because the low voltage protection of the inverter is triggered,the inverter locks out the output,and eventually leads to a non-stop accident.In order to ensure the safe and stable operation of the unit,the thermal power plant applies a set of anti-low voltage ride-through devices to the coal feeder inverters.The principle of low-voltage ride-through control of inverters were analyzed.The performance of three low-voltage ride through retrofit schemes were compared.Combining with the characteristics of the field,the solution of ＂ DC 220 V ＋isolated power module for the plant＂ was chosen and verified.