In order to improve the quality of electricity in large scale power systems, stability of power system has to be achieved. This can be done by the means of preventative diagnosis of power equipments and protection, monitoring and control of the power system. Since the recent adoption of digital controllers, an improvement in stability was observed; in particular, IED, which contained self-diagnostic abilities such as fault tolerance, allowed for automatic recovery via redundancy or switching-over functions should there be faults with the equipments. Furthermore, communication lines have been hugely simplified, thus adding to the improvement in stability significantly. Taking these error reports and forecasting emergency reports and by effectively responding to them in the overiding controlling systems, high levels of system stability can be obtained. Power Management System that is being applied to automated power sub-stations, takes the IEC61850 international standard as its specification. In this paper, additional research into achieving stability of already developed PMS system and also the stability of the overall system was carried out, and the results of development of communication servers, which play a pivotal role in connecting systems, are stated.