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You can change load in the static data, adding a load in a bus. In pyhton, the script is: psspy.load_data_3(50061,r"""1""",[_i,_i,_i,_i,_i],[ 1.4, 1.05,_f,_f,_f,_f]) 50061 is the bus where I aplied the load, P = 1.4 MW and Q = 1.05 MVAr