Smart grids represent the future of power generation, distribution and transmission systems. Integration of renewable energy sources with fluctuating power output into the grid requires constant monitoring of grid assets. Wireless Sensor Networks (WSNs) provide an efficient monitoring infrastructure for data collection from multiple locations for extended periods. The aim of this study is to investigate the lifetime of the energy harvesting WSN nodes inside a substation, where the sensor nodes exploit the abundant electromagnetic field in the substation environment. Performance results show that the impact of harvesters on node lifetime is crucial compared to available power management systems, when realistic substation channel conditions are considered. (C) 2018 Elsevier B.V. All rights reserved.