An evaluation procedure for estimating voltage ripple caused by cloud shadows moving over high-penetration PV distribution networks

Voltage ripple is a very old problem in power systems and has been, for the most part, solved for decades. Now, with the likely emergence of widespread photovoltaic generation on rooftops, combined with moving cloud shadows, voltage ripple problems could reappear. For example, if 50% of the load on a power distribution feeder in full sun is supplied by distributed PV, voltage ripple will obviously occur as clouds drift over, reducing individual PV outputs to 30% of full-sun levels. The question is “how large is the voltage ripple likely to be?” This paper presents a cloud shadow model, procedure, and simulation tool suitable for answering the question.