Monitoring System Condition

The importance of monitoring the performance of power system and equipment has steadily increased over the years. In the beginning, transmission lines had more capacity than was utilized and, in general, transmitted power from point to point, with few parallel paths. In addition, relays were provided with targets to indicate which relays operated and which phases were faulted. The evaluation of system faults, therefore, was relatively straightforward. As systems matured, transmission lines were connected in networks and more heavily loaded so the analysis of faults became more complex and monitoring of equipment performance became essential for reliability and maintenance.