Problem

Inverter controlled equipment stops when detecting a fault in the commercial power supply.

Measurement

The following items should be measured simultaneously:

• Voltage fluctuation – The output voltage fluctuates regardless of the demand caused by the wind speed difference.
• Frequency fluctuation
• Transient overvoltage, Waveform distortion – Generated by lightning strikes and grid switching
• Inrush current
• Harmonics
• High-order harmonics
• Flicker

Source : Guidebook for Power Quality Measurement, HIOKI E.E. Corporation