An integrated design approach for power supply intake scheme in circle line

Circle line (CCL) is approximately 33 km long and comprises of 29 stations. The original power supply intake scheme consists of three (3) 66 kV intake substations located strategically around the line. This design ensures that sufficient redundancy is built into the system to mitigate the event of power outage of any one of the power supply sources. Difficulties in identifying suitable land resulted in the implementation of an integrated design approach for the CCL power supply intake scheme. The existing Singapore mass rapid transit (SMRT) operated intake substations at Bishan Depot Intake and Buona Vista Intake were found to be suitably located in relation to the final CCL alignment making them ideal intake sources for CCL. The use of the existing intakes eliminates the need to identify and secure suitable land for the substation and also brings about savings in both construction and maintenance cost. This paper gives an overview of the considerations in the planning and use of existing intake substations to maintain a reliable and robust power supply for the transit network in Singapore.