According to Article 3(2)(22) of the Network Code on System Operation, blackout state means the system state where the operation of part or all of the transmission system is terminated.
Article 18(4) of the Network Code on System Operation
A transmission system shall be in the blackout state where at least one of the following conditions is fulfilled:
(a) loss of more than 50% of demand in the concerned TSO's control area,
(b) total absence of voltage for at least three minutes in the concerned TSO's control area, leading to the triggering of restoration plans.
The TSOs of GB and IE/NI synchronous areas may develop a proposal specifying the level of demand loss at which the transmission system shall be in the blackout state. The TSOs of GB and IE/NI synchronous areas shall notify this instance to ENTSO for Electricity.
Other system states are:
- normal state,
- alert state,
The criteria to be used by the Transmission System Operator (TSO) when classifying the system state of its Transmission System as blackout state are as follows:
i. loss of more than 50% of load in the TSO responsibility area; or
According to Article 40 of the Emergency and Restoration Network Code (NC ER) each TSO, when in the blackout state, is entitled to gather the following information:
(a) from Distribution System Operators (DSOs) the necessary information about at least:
(i) the part of their network that is in island operation;
(ii) the ability to synchronise parts of their network that is in island operation; and
(iii) the capability to start island operation;
(i) the current status of the installation;
(ii) the operational limits;
(iii) the full activation time and the time to increase generation; and
(iv) the time critical processes.
Network Code on System Operation, Article 3(2)(22), Article 18(4)
Emergency and Restoration Network Code (NC ER), Article 40