Design Criteria For The Service Continuity Of Road Tunnels

This paper presents the design criteria for electrical systems in road tunnels to guarantee the operational continuity of the safety and other services in the event of a road accident, with or without the development of a fire. Two essential criteria are based on the module and zoning of the road tunnels which allow for a configuration of the supply systems as a special comb system. This structure presents the main distribution with continuous development, in a protected area at the bottom of tunnel, and its backbones branching into each module to reach the luminaires and jet fans above in the vault. This paper deals with the correct sizing of the transformers and the engine-generator sets adequate to the loads, to the overcurrents and electrical disturbances determined by the inrush currents and re-activations of the jet fans, by load imbalances, by the harmonic contribution of electronic equipment such as the soft start converters. Tunnels require safety measures that prevent and mitigate critical events in accidents that can jeopardize human life and the tunnel systems themselves. This paper highlights the need for documented verifications of the adequacy of normal power supply and emergency ventilation to support fire mitigation.