Monitoring and determination of system states by TSOs
Article 19
1. Each TSO shall, in real-time operation, determine the system state of its transmission system. 2. Each TSO shall monitor the following transmission system parameters in real-time in its control area, based on real-time telemetry measurements or on calculated values from its observability area, taking into account the structural and real-time data in accordance with Article 42: (a) active and reactive power flows; (b) busbar voltages; (c) frequency and frequency restoration control error of its LFC area; (d) active and reactive power reserves; and (e) generation and load. 3. In order to specify the system state, each TSO shall perform contingency analysis at least once every 15 minutes, monitoring the transmission system's parameters defined in accordance with paragraph 2, against the operational security limits defined in accordance with Article 25 and the criteria for system states defined in accordance with Article 18. Each TSO shall also monitor the level of available reserves against the reserve capacity. When carrying out the contingency analysis, each TSO shall take into account the effect of remedial actions and the measures of the system defence plan. 4. If its transmission system is not in normal state and if that system state is qualified as a wide area state the TSO shall: (a) inform all TSOs about the system state of its transmission system via an IT tool for the exchange of real-time data at pan-European level; and (b) provide with additional information on its transmission system elements which are part of the observability area of other TSOs, to those TSOs.