Management of interruptible loads for power system security and operation

The paper critically analyzes the state of the art of the procedures to ensure the security of power system operation with respect to the introduction of interruptible loads. A short overview of the existing international approaches is presented. The potentiality of load curtailment as an ancillary service is underlined. The benefits for the power system in terms of increased exploitation of the network capability-with particular attention to the increase of total transfer capacity (TTC) across network sections-are emphasized. A new definition of security is discussed as a consequence of the use of interruptible loads not only into emergency conditions but also during normal and alert operation. Some preliminary hints for the specific situation of the Italian Power System are presented. The results of a research activity on the possible use of the load curtailment approach to increase the TTC in the Italy-Europe sections are reported.