This report presents three methods to identify the transmission consumers in power systems that take advantage of new or existent reactive power sources and, consequently, to allocate its acquisition costs among these consumers. The methodology to obtain the allocation factors, applied to each of the agents, takes into account the analysis of a transmission outages set with their respective probabilities. Each one of the proposed methods uses a different criterion to measure the benefit due to the reactive support provided by such equipments. The mentioned criteria are: voltage deviation, load shedding and reactive power injection. All these methodologies are very used in operational and expansion planning studies, as well as power systems reliability analysis. The application of the methods is shown in case studies with two systems, being the first a 5 bus simplified system and the other, the IEEE-Reliability Test System (24 buses), in which a three years horizon is considered for the reactive power compensation equipment remuneration.