Inductive Energy Harvesting for the Monitoring of Power Cable Systems

Inhalt:
The monitoring of electrical equipment is an essential part of the secure and reliable operation of energy grids. Real-time information about the operating state of various assets can be used to optimize the grid usage and ensure an economically optimal dispatch and power flow. In the case of power cables, a monitoring system can enable a dynamic management of thermal limits. The relevant data required are the temperature of the cables and the state of the isolation, which can be assessed through partial discharge monitoring. One obstacle for the constant monitoring of cables, as opposed to transformers and switchgear, is the energy supply for the monitoring system, because there is usually no auxiliary supply available for underground cables. The approach discussed in this contribution is a supply using the power in the cable itself via an energy harvesting system. The paper describes the theoretical foundations, design, and dimensioning of such an energy harvesting system for the use at high-voltage cable joints. The investigations include a derivation of the general relations between the electrical parameters and the geometry, a verification using a finite volume simulation and an experimental prototype. The design of the complete system including the battery management system and the voltage converter is also discussed.