1）Harmonic

It will cause additional loss of equipment, affect the normal operation of equipment, accelerate the aging of equipment insulation, metering deviation and protection misoperation, adjacent equipment interference, etc. at the same time, the series resonance and parallel resonance in the power grid will amplify the harmonic and cause more serious harm.

2）Voltage fluctuation, flash edge, depression and power supply interruption

Power electronic devices based on computers and microprocessors are the most sensitive to such problems, such as stop working, data passing and file damage. Internal components will also be affected by them, so as to reduce their service life.

3）Three phase voltage unbalance

The transformer is in asymmetric operation state, resulting in increased transformer loss, excessive zero sequence current, local metal parts heating up or even burning. Three phase electrical equipment will cause current imbalance, resulting in the increase of motor torque, temperature rise, efficiency decline, energy consumption increase, vibration and so on.