Coal and Mine
Reactive power compensation solution in coal mining industry
Release Time:2015-12-25

Analysis of current electrical energy quality situation in coal mining industry 


Shaft hoist is of dynamic load, and it takes several minutes for a working cycle from start, stabilization to brake of the hoist. In this process, there’s a great change for reactive power. Power factor is minimum at rising stage (about 0.2) and higher at brake stage. And the hoist is started frequently. Generally it takes 2-3 minutes for a bucket to be raised from shaft bottom to shaft top, and acceleration time is about 10-12 seconds. Moreover, direct current system supplying power with thyristor or AC-AC variable frequency speed control system is generally used in big power hoist, which generates a large quantity of harmful high sub-harmonic.

 

Solution 


ISVG can stabilize grid voltage, improve power factor, effectively suppress high sub-harmonic and perfectly solve electrical energy quality problems caused for a hoist working under heavy industrial load.



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