Controlling and monitoring Singapore's underground grid

Designed and operated as a totally underground system for environmental and aesthetic reasons, underground cables are exclusively used in the Singapore transmission network at voltages up to 400 kV. Fully metal-clad sulphur hexaflouride (SF/sub 6/) gas insulated switchgear (GIS) is used at all transmission levels to circumvent land scarcity in the siting of substations. To maintain and ensure reliability and availability of transmission facilities, technologically advanced systems for protection, control, supervision, and online diagnostics are employed. These are: computer-based integrated substation protection and control monitoring systems, partial discharge measurement systems, and distributed temperature sensing systems. These systems are discussed in this paper.