  Conservation voltage reduction (CVR) has been widely implemented in
distribution networks and helped utilities effectively reduce energy and peak
load. However, the increasing penetration level of solar photovoltaic (PV) has
affected voltage profiles and the performance of CVR. It remains an outstanding
question how CVR and solar PV interact with each other. Understanding this
interaction is important for utilities in implementing CVR and assessing its
performance. This paper studies the impact of solar PV on CVR in a real
distribution system in the Midwest U.S. using comprehensive simulations. We
have considered various PV allocations and penetration levels, as well as
different inverter control modes according to IEEE Std 1547-2018. Three metrics
are used to quantify the impact of solar PV on CVR: voltages at the substation,
voltage distribution across the network, and energy consumption reduction due
to CVR. The results show that the allocations of solar PV have the most
significant effect on the CVR performance, where a dispersed allocation of
solar PV will help flatten voltage profile and achieve deeper voltage
reductions at the substation, less energy consumption and line losses.
