This paper presents the place and role of modern management strategies and maintenance of the electrical power system, as well as a general concept of a power system with the significant role of diagnostic centre (DC) in it. In proposed concept, DC is necessary for remote monitoring and diagnostics the most operational parameters in the power plants. DC should perform remote monitoring and detection various production and process parameters using up-to-date software, servers and measuring and telecommunication equipment. These monitoring parameters are useful for early fault detection and failure analysis. Early fault detection is possible due to sophisticated remote monitoring systems which fit into the modern conception of condition-based maintenance. Increased reliability is a direct consequence of the reduced number of failures and unwanted impact on the efficiency. Continual monitoring of power generation and plants will allow service teams to react faster and minimise downtime of critical facilities. Operational parameters which are monitored and analysed by the diagnostic centre should cover all aspects of remote monitoring of generation and transmission of each generator-transformer unit of a power plant. DC should also perform remote monitoring of all associated equipment and installation, whether it is a hydro or thermal power plant.