Ancillary services forminimizing the impact of resonances in low voltage grids by power electronics based distributed generators

This paper proposes a solution for the minimization of the impact of resonances due to parallel capacitances in the grid. This solution is a combination of two additional (ancillary) services of power electronics converters, namely Virtual Parallel Capacitance Reduction (VPCR) and Virtual Resistive Harmonic Damping (VRHD). VPCR is an ancillary service that lets a power electronics converter generate a current to compensate currents through capacitances placed in parallel with the grid, for a frequency range that includes the fundamental and a number of harmonics. VRHD is an ancillary service that gives a power electronics converter a resistive behavior for a number of harmonics. This action will bring extra damping to resonances in the grid. Results of laboratory validated computer simulations with a model of a small single-phase inverter for DG, will give insight in the effect of the two ancillary services, VPCR and VRHD that are implemented.