As there is no slack bus element in simulink, how to device such a bus so that the voltage can be set, and the active and reactive power can change automatically according to different load conditions? My need to devise simple distribution systems which have five buses, they are all connecte in series. Four of them are connected with 4 identical loads, the first bus from electrical source should be a slack bus but I am confused that how to model it. Any suggestions are welcom.. Thank you.