Project Synopsis
National Grid’s (NG) ambitious London Power Tunnel project sought to meet the city’s increasing energy demands whilst linking it to new, renewable sources of energy. This was achieved via a network of tunnels, that could be easily maintained and not disrupt the bustle of the largest urban economy in Europe.
A series of three, up to 60m deep tunnels were bored out beneath the city to house the HV cables, forming part of the electricity transmission network carrying up to 20% of the capital’s demands. PDS provided the SCADA system to oversee and take control of the various subsystems dedicated to the structure, ensuring an optimal tunnel environment.
Project Overview
The array of subsystems that required management was extensive, including Ventilation, Gas Detection, Radio, Drainage and Fire Detection. The entire tunnel and its supporting structures are managed through our SCADA system.
The ventilation system was of particular importance. Without the system working adequately, tunnel temperatures cannot be regulated and the HV cables will overheat. Twelve headhouses sit above shafts connected to the 20-mile tunnels, with either a fan or damper dedicated to maintaining suitable ambient temperatures within the tunnel. The SCADA system presents the status of each fan and damper, providing insight into how the tunnel is functioning and allowing changes to be made. A SCADA system in a critical piece of infrastructure requires an extremely high degree of availability. To guard against the likelihood of failure, we designed a high integrity, dual redundant PLC system providing: automatic and manual control as well as switching and alarm functions for all the sub-systems and associated equipment. The system is based on a high availability, hot standby / dual server configuration, capable of managing the tunnel without constant supervision in an unforgiving, industrial environment.
Throughout the design and delivery of the project, PDS worked collaboratively with the M&E contractor VVB Engineering, the civils contractor Costain and National Grid to ensure the smooth phased rollout of the systems across a period of many years. The success of the project now allows HV cables to help supply power to 9 million people deep under the city, unnoticed.
“PDS delivered the SCADA system on the National Grid London Power Tunnels Project, through the M&E contractor, VVB Engineering LTD. Through a fully coordinated approach, VVB and PDS delivered the SCADA and M&E systems to budget and ahead of program”
John Johnson
TMIET, WB Commissioning Manager
