7.4 Underground 22kV Ring Network Fully Controlled by SCADA
SPPG’s SCADA has remotely monitored and controlled its entire 22kV network since Financial Year 1999/2000. This enables engineers to locate any equipment tripping in the system instantaneously and to act quickly in restoring supply. The SCADA enables the 22kV network to be operated in a closed-ring mode. In such a network, supply to customers remains available even if one part of the ring is broken due to cable fault. The system increases productivity and improves the effectiveness of SPPG’s distribution network operation. This system provides a more proactive way of attending to power failure. There is no necessity to rely on customer complaints received to ascertain the nature of 22kV power failure.
Electricity is transmitted in Singapore from power stations to load centres through the 400kV, 230kV and 66kV transmission networks. The 22kV network, which forms the bulk of the distribution system, in turn distributes power from the transmission system to the customers. Hence 66kV/22kV transformers constitute the major interface between the transmission and distribution systems.