GSM link for power utility

South Australian electricity distributor, ETSA Utilities, has incorporated around 12 GSM-linked telephone dialling units (TDU) as part of the new remote control and monitoring system for its state-wide electricity distribution network.

Teaming a cellular phone network with PLC technology from Rockwell Automation, the TDUs provide a remote telemetry unit (RTU) solution for the widely distributed control system.

The TDUs were specially developed by Adelaide systems engineering group Camms for deployment in substations that do not warrant continuous communications, but which still require status monitoring. Each TDU includes an Allen-Bradley MicroLogix 1500 controller from Rockwell Automation, plus a GSM modem; these enable it to relay faults to ETSA's Network Operations Centre using a cellular network's short message service (SMS).

"The text messages are received by a centralised ControlLogix controller, which makes the information instantly available to the third-party SCADA system overseeing ETSA's entire network," says Steve Drinkald, Camms Standards Co-ordinator, System Integration.

Designed and implemented by Camms, the complete project involved remote monitoring and control of ETSA's electricity distribution network, which is dispersed across 178,200 square kilometres and comprises 370 substations. "Data is otherwise collected via radio, leased line, copper or fibre, and fed to data concentrators in strategic locations around South Australia," said Drinkald. "It is then directed to the Network Operations Centre utilising the DNP 3.0 communications protocol, which allows time and date stamping."