Typically utilities impose a step voltage change (or flicker) limit on their transmission and distribution systems, usually around 2-3%.  This limit often drives the maximum size of a capacitor bank that can be switched or the rating of the largest line-started induction motor that can be started. Step voltage changes that are less than 2% are not perceived visually by their customers nor does it usually impact customer processes, while values greater than 2% that occur with greater frequency can cause lead to customer down-time and excessive wear and tear on utility equipment.  Changes in the wind or solar emissivity, impact of clouds, highly affect these types of generation on the distribution system.  The change in MW output can be great enough to violate the 2% step voltage change.  As renewable generation increase, solutions are needed, and distribution STATCOMs can solve these and many other problems on the distribution system.

Conclusion:

In summary, STATCOMs can effectively solve voltage problems, be they step voltage changes or just voltage regulation issues, on distribution feeders. Whether the distribution generation is located near a substation or on the tail end of a feeder, STATCOMs are more than capable of dynamically regulating a distribution line’s voltage profile to keep it within a 2% step voltage/flicker limit.