National Grid Gas Transmission
James McCormick, Steve Johnstone, box.GT.firstname.lastname@example.org
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Remote isolation valves are currently installed on the National Transmission System (NTS) at Multi-junctions, Compressor Sites and Entry Points to allow a pipeline to be isolated remotely by Gas Network Control Centre. However, there over 200 block valve sites which have local operated valves and would require staff to visit the site to operate the valves and there are 39 Exit Points where the main pipeline isolation valve can only be operated locally at the site.
The risk to the pipeline network is controlled by a number of processes and procedures to avoid damage to a pipeline; however in the event of severe damage, leak or rupture, it would be necessary to isolate and de-pressurise the affected section of the pipeline. In case of emergency the current approach would be to send staff to the block valves either side of the incident to isolate the pipeline. In the event of a major incident then the nearest remote operable valves would be used and the gas supply to the exit points between the two remote valves would be lost. This approach relies on a quick response time from staff to attend site with sufficient equipment to gain access to the valves, which is in some cases located in below ground pits requiring any accumulated water to be pumped out before the valve can be operated.
The traditional way to provide electrical power to these types of facilities is to use the local electricity company’s services to provide the supply. The cost for this can be extensive and therefore prohibitive. There are alternative methods to get power to remote sites which National Grid are looking to investigate.
Where possible it is preferable to reduce the carbon footprint, the most common configuration to do this is to use PV cells and/or wind turbines with an electrical supply. Project NIA_NGGT0039, Renewable Power on Remote Installations, ascertained that it is feasible to provide the electrical power for existing or new National Grid installations from just renewable power sources, however work to date indicates there are a number of factors with a high degree of variation, including options for combined solar and wind, valve type, actuator type, site location, and season which determine whether the solution is a practicable one for the site. This work will trial and demonstrate the renewable power technology in a simulated environment.