Smart grids LPTV behavior - real problem in real grids?

In normal operational states and for standard customers the LTI (linear time invariant) impedance based power grid model sufficiently well approximates its real behavior. With the introduction of DG and smart grids, accompanied with the growing power of measuring/data processing instrumentation, the drawback of LTI descriptor is observable and more accurate models are required. Such extension is with the LPTV (linear periodical time variant) grid modeling. The interest in LPTV power grid properties investigations is growing due to less centralized DG and massive implementation of intelligent switched loads (LED illumination, electrical cars chargers etc). With the new solution of the grid impedance analyzer the LPTV properties of the real University grid were investigated. With the use of simulations the experimental data were extended, giving deeper insight into quick time varying grid behavior. In conclusions some propositions for the future research in the field are proposed.