Computation of Voltage Flicker With Cloud Motion Simulator

Photovoltaic (PV) resources have introduced themselves as a main player in impacting different aspects of the power system from system planning to voltage stability. The main challenge of employing PV systems is the intermittent nature of solar energy. The irradiance variations are mainly caused by cloud motion and the associated shadows moving over solar arrays. Thus, when dealing with high PV penetration levels, simulation of cloud shadow motion and its effect on the power system is of interest. In this work, a cloud motion simulator (CMS) that incorporates quasi-steady-state power-flow analysis is introduced. Moreover, how the CMS parameters can be estimated from field data is discussed. Cloud motion and the consequent voltage fluctuations can cause voltage flicker issues. A new and practical method for calculating short-term flicker severity based on the IEEE 1453-2015 standard is introduced and discussed. Effects of cloud speed, number of clouds, width of clouds, and time interval between clouds on short-term flicker are investigated. In addition, the effect of using distributed models for larger PV systems on flicker severity is investigated.