Remote power feeding-report from a field trial

Remote power feeding (RPF) is a new way of achieving cost efficient back up for telecom. By remote power feeding, AC power is generated centrally and distributed via separate dedicated lines to telecom sites located within a reasonably limited area. Great savings are possible by decreasing the amount of batteries needed at every telecom location, and limiting the numbers of reserve power installations. Batteries are very costly to purchase, install and maintain. In addition to this secondary costs arise which can be even higher floor-space, floor reinforcements and extra rectifiers needed for recharge. The environmental burden on the society shall not be neglected-lead acid batteries, although recycled to a great extent, lead to environmental problems. To greatly decrease the amount of batteries would be a great advantage. The obvious solution, to use an engine-generator set, is not advantageous when it comes to locations where only low power levels are needed. Small generator-sets tend to cost much per power unit compared to large-ones and be less reliable. By using a large generator centrally located and where good maintenance can be afforded the total cost can be low. In a pre-study by Telia and Ericsson it was concluded that great cost savings are achievable. Fundamental to this solution is a design using as much as possible standard, off-the shelf components. Because the prestudy produced such a favourable prospect for RPF it was decided to start a field trial. This paper gives details about the project and its background. It point out advantages, possible technical solutions and problems.