In industrial plants with dynamically varying load profiles, the problem of increased charges for over-contracted reactive power consumption is very common. To eliminate these charges, reactive power compensation systems are used. This article presents a case study of an automatic reactive power compensation system in an underground mine where a thyristor hoisting machine is used. To reduce the higher current harmonics of the hoisting machine and compensate for the reactive power of the PCC (Point of Common Coupling), the main reactive power automatic compensation system and an ASVG (Advanced Static Var Generator) with a nonstandard control loop were used. The article considers aspects of the operation of the ASVG, locally with the hoisting machine, and also as a master-controlled device that is part of the reactive power automatic compensation system. This part of the article is based on measurements taken in a mine. The reactive power automatic compensation system considered in this article has been successfully implemented, improving PQ (Power Quality) and eliminating additional overcompensation charges.