A mix balanced-modal truncations for power systems model reduction

In this paper, a new model reduction technique mixing the balanced and modal truncations is proposed for power systems. Usually, only the power transmission lines are approximated such that, when used with the rest of the power system, the phenomena of interest are reproduced. Our approach is structural since it is based on the reduction techniques of the dynamical systems and consider the full power system rather than the lines alone. It is shown that, to obtain a good approximation with the balanced or modal truncations, a large number of dynamics are needed to be kept in the reduced model. By mixing the balanced and modal truncations, a much lower order reduced model is obtained and the behaviour of the full system is faithfully reproduced. This result is useful in practice since it opens the way to improve the numerical simulations and behaviour analysis of power systems by making easy the digital implementations. This new technique is checked by simulation tests in Matlab and EMTP.