WAM systems have delivered key measurements that have been used to prepare, observe, and improve an adequate dynamic system behavior. Pan-European Data Exchange Real-Time Phasors from PMUs Parameters Estimator Series Reactance Series Reactance Shunt Susceptance Line Temperature Dynamic Thermal Rating Power System Reliability and Safety figure 4. A logic diagram of a line temperature calculation. Permanent power system monitoring with the help of WAM systems enables the system operator to benefit from the support of a system "scanner" with respect to overall dynamic system behavior. For this approach, the most efficient way of data collection and compilation consists of overlapping relevant measurements from far away substations of the highly meshed CE system; see Figure 8. At a wide area level, PMUbased applications offer a very useful picture of the system state, permitting the correlation and synchronization of the most vital information about it. Figure 8 shows a public web page created by Swissgrid that collects real-time data 12% 10% Curtailment (%) 8% 6% 4% 2% Ja nu a Fe ry 2 br ua 012 ry 2 M ar 012 ch 2 Ap 012 ril 20 1 M ay 2 2 Ju 012 ne 20 Ju 12 ly 20 Au g Se us 12 t pt em 20 be 12 r2 O ct ob 012 N ov er em 20 12 b D ec er em 20 be 12 r Ja nu 201 2 ar Fe y 20 br 1 ua ry 3 2 M ar 013 ch 2 Ap 013 ril 20 1 M ay 3 2 Ju 013 ne 20 Ju 13 ly 20 Au Se gus 13 t pt em 20 be 13 r2 O ct ob 013 er 20 13 0% figure 5. A comparison of curtailment on an overhead line over two years. 44 ieee power & energy magazine september/october 2015