The contribution of failure analyses to transmission network maintenance preferentials

Transmission network is the core of an electric power system that connects power plants and electricity consumers, as well as the adjacent systems. Due to its central position in the system and on electricity markets, the transmission network must be safe and reliable. In achieving this goal the key role is played by maintenance. The main task of maintenance is to keep the transmission network technically operable during its life and to reduce the likelihood of failure at an acceptable cost. Transmission network maintenance in Croatia is performed periodically, at regular intervals, or in dependence on the condition of network elements. Failures of the transmission network elements cause disruptions in the operation of the transmission system and sometimes power supply interruptions, thus increasing the costs of maintenance. Failure data are stored in a database which helps to calculate the transmission network reliability indices and to make various statistical analyses. An analysis of the history data on failures in the transmission network elements helps in maintenance and replacement prioritization.