Plots a power grid similar to plot_pg in PlotPG.jl and colors the edges according to the difference in branch loads in ndd and ref_ndd. Possible plot settings can be seen in PlotUtils.jl.
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function plot_pg_pf_diff(
ndd::Dict{String,<:Any},# NDD with (new) power flow
ref_ndd::Dict{String,<:Any},# NDD with reference power flow