refactor power_injection_vector_pu -> sj_per_unit

Author: NLaws

src/multi_phase_model.jl

@@ -59,7 +59,7 @@ function build_bim_rectangular!(m::JuMP.AbstractModel, net::Network{MultiPhase},
             continue
         end
 
-        Pj, Qj = power_injection_vector_pu(j, net)
+        Pj, Qj = sj_per_unit(j, net)
         Sj = Pj + im * Qj
         Sj = hcat(Sj...)  # time X phase