Paper presents a practical solution to improve power factor in a textile plant substation using a power factor controller with six capacitors banks. A wireless signaling installation was developed to display the capacitor banks connection to the substation's grid. The power factor controller was implemented into practice. Experimental measurements were made with a power quality analyzer operating in three cases: one case without regulator and other two cases with regulator (one with an unexpected fault in the system and one without fault). It was found that the use of six capacitors banks with the same large value, is not the right solution to obtain a fine adjustment of reactive power in low voltage electric grid.