Measurement, modelling and real-time calculation of medium voltage cable temperatures

Abstract

The ever-increasing numbers of decentralized production units that are connected to the distribution networks cause a variety of challenges. When possible, the DSO tries to connect these units directly to existing distribution cables in order to have production and consumption close to each other. However, these networks were usually not designed to accommodate such high powers, which could result in over-voltages and/or overload of the cables. Often, the only option is to reinforce some of the feeders. In some cases, however, this would lead to very high social costs and other solutions should be considered. As the renewable energy sources such as wind turbines have a fluctuating power output, the high loading of the cables is only present for a very short period of time. A combination of automatic curtailment and flexible ampacity limits by applying dynamic line rating (DLR) could reduce the necessary investment costs. When applying DLR, a temperature measurement or calculation is needed. Therefore, in this paper, the measurement, modelling and real-time calculation of the cable temperature is discussed.