The designing and simulation of passive filters used in urban transportation substations

The paper presents the features of passive filters and some of the topologies used for the improving of power quality. One has in view aspects on the designing of passive filters tuned for some harmonic components. One presents some recordings and numerical simulations made over the electric signals from a substation used for the supplying of a d.c. line of 600 V. Based on the obtained results one proposes solutions for passive compensations with the consideration of a number of filtering components that depends on the compensation necessities. In order to verify the compensation efficiency, through SPICE simulation, one estimates the effects of compensation correlated with the number of passive filtering cells.