All natural gas in the UK passes through National Grid’s national transmission system on its way to UK consumers. As the sole owner and operator of gas transmission infrastructure in the UK, National Grid ensures that our gas is available where and when it is needed. Although our gas is owned by the gas supplier until it reaches the 10.9 million consumers across the UK, National Grid is the sole owner and operator of gas transmission infrastructure and is responsible for this gas whilst it is being transported.
Our gas leaves the transmission system and enters the distribution networks at high pressure. It is then transported through a number of reducing pressure tiers until it is finally delivered to consumers.
At various points throughout the distribution network the gas pressure is monitored and controlled at a series of loading stations. These stations provide a checkpoint for measuring and monitoring the gas pressure and also provide an access point for a manual over-ride facility in the event of testing, emergencies and power outages.
MGA Controls Ltd has supplied National Grid with the Watson Smith 422 I/P convertors for the control of gas, flow and pressure at various loading station sites across the UK. The Watson Smith model 422 I/P converter provides an important fail freeze function whereupon it retains its last input signal in the event of a power cut and holds the output where it previously was to ensure continuity of gas flow. The gas will remain at a constant pressure based on the last signal received and only when the power is restored and the signal changes, will the I/P change position to the new desired output.
Another important safety aspect of this product is the ‘captured bleed’ feature. This prevents gas from venting to atmosphere and thereby creating a potentially dangerous and explosive environment.
For more information on Watson Smith I/P converters click here.