Power System Simulator is graphical editor for power system modelling. Application implements element connections in natural way. After solving, power flow results are shown on the same graph. It also shows actual active power flows which are represented with arrows on power lines. Problems are solved using sparse matrices. Thus, user does not need to enter node numbers. Nodes are represented with names which is more obvious way for modell understanding. Area of usage: Electrical Egineering, Power System Modelling and Optimization.