Energy Scavenging for Monitoring of Overhead Power Line Networks Thomas Keutel , Xinming Zhao, Olfa Kanoun Chair for Measurement and Sensor Technology Chemnitz University of Technology, Germany *Thomas Keutel, +49-371/531-36523, thomas.keutel@etit.tu-chemnitz.de Abstract: The monitoring of overhead power line networks is becoming increasingly more challenging because of the power distribution of renewable energy resources. The use of ambient energy is important for a maintenance free supply of a wireless monitoring network. Generally, the electromagnetic field resulting from the AC current and the electrostatic field resulting from the AC voltage can be used. Nevertheless, the energy scavenging from electrostatic field shows decisive advantages because of availability, stability during operation and reliability. In this contribution we show the feasibility for the realisation of an energy scavenging unit. Theoretical investigations and simulations show that the distribution of the electric field in the immediate neighbourhood of the conductor shows a high gradient to the environment which can be used. The evaluation under realistic conditions in a high voltage laboratory show that through optimisation of the scavenging element an improvement of the amount of energy can be realised. Keywords: Energy Scavenging, Overhead Power Line, Electrostatic Energy Conversion, Wireless Sensor Network I INTRODUCTION Overhead power lines play an important role for a long distant electric power transmission because of the low cost for the transmission compared with buried cables also in the future. Their monitoring is becoming increasingly more challenging because of the effective charging of the grid [1-6]. Furthermore the distribution of new developed renewable energy resources, for example offshore wind farms, takes the existing transmission grid to capacity limits [7]. The amount of transported energy is strongly dependent on environmental conditions like temperature or snow [3]. In order to maintain low installation and maintenance costs, a completely wireless sensor network is aspired within the BMBF-project ASTROSE. For the power supply of the wireless nodes a new approach for energy scavenging was developed to supply a device from the direct boundary field around the conductor. II SENSOR NETWORK Theoretical investigations of the electrical and mechanical behaviour and also the charge of power lines show that the temperature of the conductor is one of the most important limiting parameter during operation of a power line network [3, 8]. For example, is there any damage or any deterioration of the conductor, the resistance (R cond ) increases together with the temperature because of power losses (P l ): 2 trans cond l I R P ⋅ = (1) Also in cases of critical high charge (I trans ) the temperature increases (s. equation (1)). Considering these facts, leads to the necessity of a monitoring system for measuring the local temperature of the conductor surface. C6.2 SENSOR+TEST Conference 2009 - SENSOR 2009 Proceedings II 207