As mentioned previously, information gathered from the process is saved in real time, to create a current picture on the SCADA application server of the process under monitoring. RTU data are saved on receipt, and any change overwrites old values with new ones.

In providing customers and the regulator with current data about the power quality of segments of the network and the network as a whole, the output statistics obtained from SCADA systems are extremely relevant. This statistic is based on the Stored Event Sequence (SES) list.

Data labelled this time (TTD) is processed every 10 seconds or every hour at cyclical intervals in the historical database. Only modified data are usually stored in order to conserve disk space. For several aspects of strategic preparation, statistical analyses, system loading and performance assessments as well as report output, data can be collected at a later date.

This data mining requirement contributes to more advanced archiving technologies, which can be tailored to identify data and storage events. These historians, storage and recovery systems with complete redundancy and versatile retrieval systems or information storage & retrieval (ISR) systems are now integral components of any DMS. They typically rely on the Oracle or SQL server connecting databases.