As a reliable power network is crucial to deliver promised electric power, cable powerline monitoring in medium-voltage networks has a great importance for distribution system operators all over the world. A considerable rate of failures in cable powerlines is referred to the cable joints. Especially during the summer period, an excessive number of joints are subjected to explosion, causing outages in different points of the power network. To this purpose, in this paper, using a simple test setup presented in a previous work, the effects of temperature on the cable joint tan delta measurement have been evaluated. In fact, the temperature is one of the possible causes of faults and, from the patterns presented in the results, the hypothesis seems to be confirmed.

Medium-voltage cable joints are one of the critical components of the distribution networks. They represent the first cause of faults and outages. Among the others, partial discharge, dielectric, and temperature measurements are the typical tests performed for investigating over the early aging of such critical components. In this paper, a new study has been completed correlating the cable joint tangent delta (Tan $\delta$ ) value to the external pressure applied on the insulating material surrounding the joint. Results confirm the presumed correlation. In fact, an increase of pressure results in a Tan $\delta $ decrease, hence in an extension of the cable joint working life.

The use of medium voltage cable joints is mandatory when dealing with power cable faults and the installation of new lines. However, such an accessory is among the top causes of faults among the grid. To this purpose, one of the quantities monitored to understand the causes of such faults is the interfacial pressure between the insulating layers of the cable joint. In this work, the interfacial pressure between Cross-linked polyethylene (XLPE) and silicon rubber has been evaluated when the cable joint experiences thermal cycles. From the results, the pressure variation caused by the thermal cycles is demonstrated. Such a phenomenon may be connected to the generation of voids and weak spots that accelerate cable joint ageing. Therefore, proper comments and conclusions are drawn.

Cable joints reliability is crucial for a smart power system. A high rate of cable failure in underground cable power networks is due to the cable joints. The causes of cable joint failure can be identified through in-field monitoring of their electrical and environmental parameters. This paper is about modular units designed to measure current, pressure, temperature and humidity. These units have been installed in Palermo (south of Italy) at e-distribuzione MV network. First results of the measurement campaign are shown as well.

The paper deals with the investigation of accuracy vs. temperature variation of inductive instrument transformers. There is still a lack of literature on this specific and nowadays very important topic. In previous works, authors presented results on effects of temperature on voltage instrument transformers accuracy. In this paper the study continues with the uncertainty sources analysis which affects the calibration setup previously proposed. To this purpose, the metrological characterization along with the Monte Carlo method have been applied in order to highlight the main positive features of the calibration setup. Results of such procedures are presented.

As reliable power network is crucial to deliver promised electric power, cable powerline monitoring in medium voltage networks has a great importance for Distribution System Operators (DSOs) all over the world. A considerable rate of failures in cable powerlines is referred to the cable joints. Especially during the summer period, an excessive number of joints are subjected to explosion, causing outages in different points of the power network. To this purpose, in this paper, a simple and cheap test setup has been designed and calibrated to perform one of the key measurements for the cable monitoring, Tan Delta. Finally, the Tan Delta of different joints have been measured using the proposed setup.