Recently constructed pipelines and their new owners, however, are often separated by phenomenal distances, even so far as to be on opposite sides of the Australian continent. Advances in pipeline control systems mean that operators are now able to have direct access to flow computers and process controllers as if the control system was in the next room, on the office LAN.
The Bristol Babcock ControlWave and ControlWave Micro Process Automation controllers are TCP/IP based systems that combine the features of Flow Computers, RTUs and PLCs. With up to three Ethernet ports, TCP/IP over serial connections via PPP and sporting an internal IP router, these systems simplify communications and are ideal for geographically diverse pipeline projects.
In the past, radios have limited a communications system to a local geographical area. As pipelines extended to more remote regions, a line of towers had to be constructed to extend a radio network to the end of the pipeline, but with communications still traced back to a base station at one end of the pipeline.
In the most remote regions of Australia, the only viable solution is satellite communications. Satellite communications permit the pipeline and its control room to be separated by wide distances. The GGT pipeline is a prime example that has been in operation for many years on a satellite link from stations in outback WA to a control room in Perth. This system is based on specialist RTU hardware sitting between the satellite IP network and the station controllers. The RTUs in this case act as a protocol converter between the satellite IP link and the local, site serial network.
RTUs have always been the backbone of control systems using a SCADA solution, bridging remote control networks and PLCs with a central control room. The drawback, as with any protocol converter, is that they also act as a communications filter. Only the information that can be converted is accessible, and any changes to the data made available in the remote control system require additional changes to the RTU to provide access to the extra data.
Bristol Babcock flow computers have always had one advantage in this area, by providing direct access to the remote flow computer. The Bristol Babcock flow computers are also RTUs and integrating this functionality means that no protocol conversion is required. All of the accessible information in the flow computer is available, without any filtering, to the central control room. If extra functionality is added to the flow computer then this is immediately available for remote access.
The direct access solution has been implemented successfully on traditional, radio based pipeline control systems, where the flow computers capabilities of remote monitoring, remote diagnostics and even remote software updates have been utilised. The next challenge is to extend the direct access functionality to the very remote pipeline control systems. The technology behind this is standard TCP/IP networking.
When the EAPL pipeline was installed from Longford to Sydney, high speed access to data was a primary objective. Radio was not going to be able to provide the bandwidth required and so a frame relay backbone was installed. At each of the major stations, a Bristol Babcock Distributed Process Controller (DPC3330) was installed that had an Ethernet port available to it. This networking option gave the direct high speed access via TCP/IP to each of the major sites, as well as permitting unfiltered, direct access to other flow computers at the same location using the hierarchical features of the BSAP protocol.
As that pipeline system was extended to Tasmania, the same solution was applied at each location. The single pipeline station now covers three Australian states, New South Wales, Victoria and Tasmania, all centralised on Longford and all accessible via the TCP/IP network.
The control room for this pipeline, however, is some 200 km away in the Melbourne CBD. Not that you would notice of course, since the TCP/IP network makes the flow computers as visible and accessible as any other computer in the same building. Now that Alinta has taken ownership of the pipeline, there is always the possibility that someone in Perth will put in a request for a monitoring workstation on a desk somewhere in WA. As long as the TCP/IP network can be extended across the Nullarbor, then the access can be provided.
The Telfer pipeline is a project that has already achieved trans-continental control. Starting at Port Hedland, which is remote in itself, the pipeline stretches its way, deep into the Western Australian outback, to the Newcrest mine site at Telfer. GasNet, the operator of the pipeline, is situated in Dandenong, a suburb of Melbourne on the opposite side of Australia.
The distance from Port Hedland to Melbourne is approximately 3,200 km. To put this distance into perspective, consider a London based control room for a pipeline system in Northern Africa (3,500 km to Cairo) or Russia (2,500 km to Moscow). Closer to home, a Singapore based control room could be conceived for a pipeline in Western China (3,400 km to Wu Han) or India (2,900 km to Calcutta).
To bridge this distance, a satellite link was installed to each location with a direct, Ethernet connection into a flow computer or PLC. As each site is brought online, it can be communicated with as easily as any other PC or data server on the office LAN. There is no requirement for an RTU or protocol converter, the Flow Computer has an Ethernet connection and is the RTU.
From its Dandenong control room, GasNet can now monitor and operate both the local Victorian pipeline system and the remote northwest WA pipeline. The success of this project demonstrates that a company can manage its assets across Australia, no matter where it wishes to base its control room.
Another benefit of such a system is control room Redundancy. The NQGP pipeline runs 400 km into Townsville from Moranbah, in northern Queensland, and yet is controlled from Brisbane, in Queensland’s southeast. Two control rooms have been commissioned, one for day to day operations and the other for disaster recovery. The use of a TCP/IP WAN permits a simple duplication of communications services to a back-up control room.
Communicating with devices via TCP/IP extends your communications options, permitting high speed networks, nation wide communications and flexibility of system design. By utilising pipeline controllers with a full suite of TCP/IP functionality, and employing wide area networks for the communications backbone, owners and operators are able to realise their goals of nation wide pipeline control systems.
“In the most remote regions of Australia, the only viable solution is satellite communications, which permit the pipeline and its control room to be separated by wide distances.”