Purpose/Aim



To meet the rising demand for electrical energy, most power grid companies are extensively investing in expanding their assets. In urban regions, old high voltage cable lines are getting replaced by newer, more efficient ones. Just fifteen years ago, the production of gas pressure cables ceased thus establishing XLPE-cables as the industry standard for high voltage cables. To replace previous gas pressure cables with new XLPE ones and thus shorten down times of the grid, the cable lines are replaced sequentially, at intervals of a few kilometers. Special transition joints connect old gas pressure cables to new XLPE cables, to shift from one cable technology to the other. The transition joint is a rather rare component in today´s energy grids and has therefore been less studied. This research aims to build an intelligent monitoring system for transition joints.

Experimental/Modeling methods

In preparation of the joint manufacturing, a digital model was built to simulate the mechanical and electrical properties of the transition joint. During the assembly of the prototype joints, numerous sensors were placed and linked to a common monitoring interface. In this way, all the vital signs of the joints can be traced and analyzed in the laboratory environment. The digital model is again used to visualize the current state and simulate the future condition of the joint. 



Results/discussion

This research project deepens the understanding of transition joints under numerous operating conditions thus improving component longevity. Bringing together all the measurement data into a digital twin will simplify the work of grid operators.

Conclusions

The combination of lab testing data and of a digital twin model greatly improves both the development and the monitoring of transition joints. The knowledge obtained through the analysis of the joints could result in faster renewal of the high-voltage cable network in urban areas, namely through monitoring improvements and the anticipation of critical operating conditions.