The report deals with the activities carried out in the field of voltage monitoring of the distribution networks regarding: i) the development of a laboratory system for the application of new Higher Order Statistics (HOS) based indicators for estimating the quality of supply on the low voltage network;

ii) the continuation of the performance evaluation activity of the new innovative functions for the characterization of voltage dips, implemented in QuEEN.

Concerning the first activity, a three-phase approach to HOS estimation was proposed for the first time, based on the estimation of higher order moments for multivariate probability distributions namely considering the three phase voltages as random variables of a unique probability density function.

The method was compared with the single-phase approach already present in the literature both through simulations and a laboratory instrument created to monitor a three-phase low voltage measurement point for a period of two weeks. The results obtained proved the ability of the proposed three-phase approach to quantify disturbances providing a global view of the quality of supply compared to the single-phase approach. As to the second line of activity, sensitivity analyses were carried out on the valid voltage dips count indices (N, N2a and N3b) with respect to the available network characteristics (Macro-areas, neutral state, length of overhead lines) by linear regression analysis.

The analysis was conducted by considering the valid events obtained with the second harmonic criterion (used in the past for regression analyses) and with the innovative one (DELFI RMS) to verify the impact of the chosen criterion on the regression outcomes. The results highlighted a strong impact of the SUD and CS macro-area variables on the counting indices which tends to increase with the considered severity index (from N to N3b); this increase is emphasized by the innovative criterion.

Besides, thanks to a non-onerous collaboration between RSE and Unareti, the development of an automated application proceeded for verifying the validity of voltage dips by crossing the service protocol data with those of the QuEEN monitoring system. The first results point out synchronization problems between the two systems even if on the available data base, net of synchronization errors, it was possible to verify the good performance of the innovative criterion compared to the current one.

The Report is available on the Italian site