Global climate change has led to a substantial modification of the climate areas as previously defined for the design of the current electricity grid, which implies a greater probability that new climate events will cause damage to it if they are not properly monitored. Furthermore, the need for energy production from renewable sources implies a request for greater flexibility in energy transport. In this context, the resilience of the electricity grid is a hot and fundamental topic to guarantee continuity and security of the service. It is therefore important to manage the transmission network in a correct and effective way and monito the state of its components in order to identify appropriate intervention strategies. For these reasons, following the analysis of market-available systems, the decision was previously made to start the realisation of a prototype optical system for monitoring high-voltage electric line conductors. A first activity made it possible to assemble the main components of the optical device for monitoring the deflection of high-voltage lines and carry out the first tests in an external environment in order to verify the functionality of the device. After that, the activity involved the realisation of the complete device to carry out the first field tests. The prototype was successfully tested in the laboratory. The results obtained confirmed the ability of this instrument to provide useful information for power line monitoring. Finally, the results are reported of the activity involving the completion of the device and in installation, last July, in a protected environment that, however, is very similar to that of a real high-voltage line, and functional tests are still underway for identifying possible problems also connected to different weather conditions. Following the experimentation, which lasted more than six months, it can be stated that the functioning of the prototype was seldom prevented by weather conditions. However, the possible incorporation of image analysis algorithms or the replacement of some optical components may be considered in order for the prototype to always be able to function.