  For accommodating more electric vehicles (EVs) to battle against fossil fuel
emission, the problem of charging station placement is inevitable and could be
costly if done improperly. Some researches consider a general setup, using
conditions such as driving ranges for planning. However, most of the EV growths
in the next decades will happen in the urban area, where driving ranges is not
the biggest concern. For such a need, we consider several practical aspects of
urban systems, such as voltage regulation cost and protection device upgrade
resulting from the large integration of EVs. Notably, our diversified objective
can reveal the trade-off between different factors in different cities
worldwide. To understand the global optimum of large-scale analysis, we add
constraint one-by-one to see how to preserve the problem convexity. Our
sensitivity analysis before and after convexification shows that our approach
is not only universally applicable but also has a small approximation error for
prioritizing the most urgent constraint in a specific setup. Finally, numerical
results demonstrate the trade-off, the relationship between different factors
and the global objective, and the small approximation error. A unique
observation in this study shows the importance of incorporating the protection
device upgrade in urban system planning on charging stations.
