Résumé : Power systems have been historically designed at a time when the production was

centralized and the electricity had to be transmitted to the loads from the closest power

plant. Nowadays, there is an increasing integration of decentralized and intermittent pro-

duction. Moreover, the energy market coupling has enabled the transfer of electric power

for economical purposes. Also, former isolated power systems are now interconnected for

reliability and financial reasons.

All of these changes make difficult to predict the future behavior of the grid. Studies

are done in order to plan for the future needs of the system. However, building new in-

frastructures takes time and it is expected that these needs will not be completely fulfilled

in all the parts of the grid. Therefore, transmission of active power could be limited by

the existing infrastructure. For example, the presence of inter-area oscillations is often

the limiting factor when a high active power is transmitted on a long transmission line

between two groups of generators. Since higher levels of active power are exchanged on

longer distances, problems of inter-area oscillations may arise in power systems previously

not affected by this phenomenon.

In this work, a measurement-based approach, able to predict in the short-term the

future behavior of oscillations, is presented. This approach is complementary to the

long-term planning of the grid.

The mandatory first step towards a measurement-based approach is to have the ability

to extract useful information among a huge quantity of data. To face this issue, some

comparisons of data mining algorithms are performed. The proposed method combines

two decision tree algorithms to obtain both prediction accuracy and comprehensibility.

The second required step for building a measurement-based model is to take into

account the limitations of the measurements. Two types of wide area measurements are

used, synchronized measurements from PMUs and traditional unsynchronized data from

the SCADA/EMS system. Oscillation monitoring using PMUs is especially of interest

and an approach is presented to post-process damping estimates. This post-processing

method consists in a noise reduction technique followed by a damping change detection

algorithm.

Finally, the method, combining these two steps, is implemented to analyze the Con-

tinental European grid. This implementation takes place in the context of the European

project Twenties. The results, using several months of measurements, are described in

detail before being discussed.