According to the conditions given in this data, the power value under the maximum load of the factory is above 0.9, so it is necessary to adopt shunt capacitor to take reactive power compensation.After installing the reactive power compensation device in the power supply system, the reactive power of the front line and transformer is compensated, so that the reactive power calculation load, apparent calculation load and calculation current of the front line and transformer can be reduced and the power factor can be increased [2].