A Realistic Irradiance-based Voltage Flicker Analysis of PV Applied to Hawaii Distribution Feeders

Voltage Flicker caused by distributed generation is widely discussed during System Impact or Interconnection Studies. Misrepresentation of voltage flicker can often delay or create barriers to entry for renewable energy projects. The simplest voltage flicker analysis for photovoltaic (PV) generation is based on perceived instantaneous irradiance dips, of approximately 80 to 90%. These post-transient simulations often do not account for time variance and stability of other dynamic system components. Analysis is presented detailing an integrated inverter model and irradiance based analysis. Representative short time scale periods of 60 seconds are collected from multiple irradiance sensors to model different levels of cloud cover. Irradiance data feeds into a multiple inverter network with voltage changes calculated over the analysis time. Ongoing utility data collection at the distribution and sub-transmission levels can be used to validate performance and true flicker related impact of PV. The value and validity of using high fidelity, realistic time-based, irradiance data is presented versus assuming an instantaneous power drop.