Touch voltage protection on Singapore MRT system

This paper generally describes the various touch voltage protection measures adopted mass rapid transit (MRT) systems. Particular reference is drawn from the practices adopted in the Singapore MRT system. There are potential hazards of electric shocks to passengers and working staff touching conductive surfaces of different voltage potentials e.g. around the platform edge particularly between the platform screen doors and train or train depot workshop area. As such, there is a need to address this concern through the application of appropriate touch voltage protection. It is recognised that prior to examining the earth (grounding) details, an important but often obscure concept of touch voltage protection must be fully understood and considered to ensure that the touch voltage protection have been properly catered for to mitigate the potential hazard. This paper also outlined the touch voltage protection methods adopted in the existing Singapore MRT depot areas. Problems experienced on touch voltage protection issues in existing Singapore MRT system are also highlighted. Provisions of touch voltage protection devices i.e. running rails to earth voltage limiting device (64P relay) and fault voltage monitoring equipment (FVME) are also discussed in the paper. Various civil provisions for touch voltage protection issues at stations especially at those stations with platform edge columns are also covered. In addition, the paper also outlines the adopted integrity measurements for installations within the protection zone for the required touch voltage protection purposes.