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Security and vulnerabilities of the electrical system

Power System Research


Antonella Frigerio

In a context of deep changes due to the actions aimed at pursuing the objectives of European energy and environmental policies, ensuring an adequate resilience of the power system with regard to exogenous and endogenous phenomena is a key objective to ensure the continuity and quality of energy supply to end users.

The European energy and climate policies, promoted by the Strategic Energy Technology Plan (SETPlan) and the Energy Union Package, are changing the electricity system making its management ever more complex. The progressive growth of the load demand supplied by non-programmable renewable generation, at the expense of the thermal power unit production, is making difficult and economically burdensome the regulation of the power network, increasing the risk of contingencies. In addition to these critical issues, the strong exploitation of the electrical interconnections between the EU Countries, created to guarantee mutual aid but nowadays more and more used for large energy transactions for commercial purposes, is increasing the risk of wide area contingencies. Last but not least, the energy system is clearly vulnerable towards extreme weather events that cause great economic losses every year.

In response to these issues, methods and tools are proposed in order to support operators. In order to evaluate quasi-online the dynamic security of large power grids, a methodology for security assessment taking into account uncertainties has been validated. A Limited Bandwidth Derivative operator has been developed to estimate the frequency and ROCOF. In the frame of AEEGSI and CEI working groups, methods for quantifying the electric system resilience when affected by extreme weather events have been proposed. At present, concerning wet-snow events the preliminary maps of ice loads and wind have been presented and they will be included on the new WOLF GIS website, and testing of anti-icing currents at WILD station are still in progress.

To improve the operational flexibility of fossil fuel power plants, a material damage law has been defined on the basis of TMF tests and a dynamic simulator of the entire plant is under development.

In response to critical issues related to environmental phenomena, with the aim to classify the seismic risk of existing arch and gravity concrete dams, two simplified methods have been developed: one ranks dams according to their vulnerability, the other evaluates the hazard of a dam-break. Furthermore several structural and hydraulic studies have been carried out: analyses of seismic records, development of experimental methods for assessing the time evolution of the AAR phenomenon in concrete dams; compliance of FLOODRISK with the Floods Directive guidelines and SPH modelling improvements on SPHERA v.8.0 (RSE SpA).