This paper introduces the effect of shunt active power filter on harmonic suppression. The shunt active power filter based on voltage detection control corresponds to an active damping, presenting the characteristic impedance to harmonic component, in addition to restraining harmonics into the power grid, but also damping harmonic resonance. A shunt active power filter is applied to two different types of power line network and then to evaluate the performance of filter and the damping resonance in different types of the network. The first power system is a 220 V distribution network. The second simplified one is a 150 kV solar power with a capacity of 444.4 MVA. It makes sure the best location of active filter via harmonic resonance modal analysis and calculates the participation factor to make the active filter filtering and restrain the resonance work well.