So that we can supply our clients safely with natural gas in the quantities within the deadlines required, various types of installation (from the source of supply to the different delivery points) make up the high-pressure transportation chain (or network) in Western Switzerland.
To transport large quantities of natural gas, it is necessary to keep it at high pressure (up to 80 bar). The Ruswil compressor station compresses the gas arriving from the north-west of Switzerland via the Transitgas pipeline in order to inject it into the network in Western Switzerland.
Ruswil compressor station
The entry points to the network are monitored by customs posts, which oversee the quantity of gas imported.
Natural gas is carried to the zone served by Gaznat via a network of nearly 600km of high-pressure gas pipelines. The pipes which make up the network vary between 24” (~ 60cm) and 10’’ (~25cm) in diameter. The pipes are welded together and buried at least one metre below ground. The entire network is protected from corrosion by polyethylene or bitumen insulation and by a cathodic protection system.
Thanks to the way the network is configured (with loops and redundancies), it can keep Western Switzerland supplied even in the event of temporary loss of the network's one feeder pipeline (via a customs post).
Block valve stations
Block valve stations are located throughout the network. They consist of a set of valves, which are usually buried. The main valves, known as safety valves, are motorised, remote-controlled and enable sections of the gas pipeline to be isolated at any time.
Trélex interconnection station
The block valve stations are often combined with metering and regulation stations (MRS). These stations extract natural gas from the high-pressure network, reduce its pressure to the appropriate delivery pressure (usually 5 bar) and measure the quantity of gas delivered. This gas is then distributed to customers, generally via a low-pressure distribution network (not owned by Gaznat).
The devices that reduce the gas pressure are called pressure-reducing valves.
For safety reasons, metering and regulating stations constantly transmit the following:
- The position of the protection devices (open or closed)
- Alarms relating to malfunctions
- The quantity of gas delivered
All Gaznat infrastructures are required to comply with the technical standards specified by the Federal Pipelines Inspectorate (IFP). For example, when a gas installation is built, all the weld seams are checked by radiography, and each element under pressure is tested at a higher pressure than that required in normal use. Each component has a material certificate and all the installation plans are rigorously inspected and approved individually by the Federal Pipelines Inspectorate (IFP).