The prospect of ever-increasing integration in the Medium Voltage (MV) distribution grid of renewable energy sources, interfaced with static energy converters, requires parallel and simultaneous advances in protection and control systems. These systems must continue to ensure the proper operation of the grid in case of failure and possibly improve the quality of supply to connected users. To this end, the application of electromagnetic transient analysis to protection systems appears promising: in fact, these techniques have the potential to locate faults effectively and detect, even quickly, faults hard to identify using the current systems.

The transient of electrical quantities following a fault can be interpreted either as a response of a dynamic circuit—for example in the case of so-called incremental quantities—or as the outcome of propagatory phenomena known as Travelling Waves (TW). In this context, a literature review was conducted on protection strategies that enable fault detection and localization by exploiting the above principles. It was seen that mature and commonly used solutions already exist with regard to the selective localization and detection of faults in high-voltage lines; in particular, the former functionality appears to be more widespread than the latter. After that, a number of methods were analyzed based on transient analysis designed for MV networks.

The highlighted methods differ in the type of network to which they can be applied, the types of faults that can be identified, and, as a whole, all the main case histories are explored. It is observed that the wavelet transform proves very popular for the analysis of acquired signals. Moreover, the different proposed architectures differ in: type and number of transducers used, number and position of detectors installed, the possible presence of communication channels.
The work presented in this Report constitutes the starting point for the future computer implementation of the most suitable techniques for the creation of protection systems for MV distribution networks in AC.