Oil & Gas
The transmission network normally consists of either an optical fiber cable with PDH or SDH line terminal equipment or microwave radio links. Sometimes-existing copper cables can be used for shorter distances. They must, however, be combined with (X)DSL modems in order to obtain higher data rates. Thus distances between pumping stations can vary from a few kilometers to several hundred kilometers in all types of terrain and climate. Standard requirements for applications on pipeline backbone networks are:
1. Telephone and PABX connections
2. Data interface to SCADA and instrumentation
3. Interface to LAN’s and WAN’s
4. Access to a satellite connection as a reroute possibility incase of a link breakdown.
The Network Management System (NMS) includes features specially designed for communication in pipeline systems. NMS is used where the communication network has a large geographical extension, and where quick error detection and short repair time are required. NMS has high compatibility and can receive alarms from other types of equipment such as power supplies, SCADA systems, radio equipment, and CCTV systems. All alarms and measurement data are accessible anywhere in the network, but are normally collected in a Network Control Centre (NCC), where the information is put in order of priority, displayed and stored. A portable PC can operate as a mobile NCC and in this way ease system maintenance.
In most pipeline installations optical fibers are used as transmission media. The cable will usually be installed away from the pipeline itself in order to increase availability of the total system. The recommended way of installing the cable is by use of cable plough technology. This is the safest and overall most economic way to place the cable in the ground. Specialized machinery is available for all environmental conditions including deserts with sand or hard rocks, swampy areas, and jungle areas. For river crossings as well as for railway and road crossings directional drilling equipment is used: A remote controlled drilling head pulls a PVC tube under the obstacle. Hereafter cables can be pulled or blown through the tube.
Whenever a high degree of safety is required for the transmission of data and control signals, parts of the network may be protected. It is possible to introduce redundancy systems on various transmission levels. Thus systems can be designed with alternative routing possibilities, i.e. ring configurations, in order to secure high availability for the process control system (SCADA system).