The Barajas airport project: how a 400 kV cable system can be safely and fully exploited

This paper deals with monitoring systems apt to qualify installation and to safely and optimally exploit one of the most advanced cable system in the world for length, voltage and power transmission. To satisfy increasing air traffic in Spain, a third runway has been realized in Barajas Airport in Madrid, Spain. Two existing overhead power lines are not compatible with the airport expansion, and have been therefore undergrounded. In 2002 Pirelli Cables y Sistemas has been awarded a contract by REE (Red Electrica de Espana) for manufacturing and installation of one of the two parallel circuits, and for after-installation test and monitoring system of both circuits, for a total contract value for Pirelli of about 17 Million €. Cables are festooned in a narrow tunnel in flat/vertical configuration along tunnels´ walls and have been successfully submitted to after-installation AC voltage test and partial discharge (PD) monitoring. AC after-installation voltage test have been performed in agreement with IEC62067 international standards. Specific experience and comparison of PD monitoring from joints with embedded capacitive taps and from link-boxes will be described. Cables temperature is monitored via three single-mode fibre optic distributed sensors (OptoPower/RTTR), providing feedback to forced air-cooling units located along the tunnel. The OptoPower/RTTR (Real Time Thermal Rating) has been requested by REE to control cables temperature and therefore regulate forced air-cooling unit intervention. System architecture and logic will be described in detail. RTTR, after installation, has been tested in order to verify data transmission network, PLC, sensors, functional logic and algorithm of control and the main PC control unit. These experiences will be described.