> but it's likely that gas main pressure is controlled by a computer.
But the failsafes are not. Overpressure is something the system is designed to handle, and those gas substations that you see every now and then in fields are the places where the overpressure regulation devices are located, and they are purely mechanical.
> It'd be shocking if a software failure could cause dozens of fires.
It would be, but this isn't that. The actuators on these systems are made with the express purpose that line fluctuations will always be slow enough to catch up with. But if a regulator fails in a bad way that might cause a prolonged overpressure with the initial change arriving as a spike, which may expose further weaknesses downstream.
So the signature of an upstream regulator failure (a big one, and a sudden one too), is fairly consistent with what you are seeing here. The software actuators would not cause a pressure rise fast enough for that initial spike and the limit settings on those actuators (which are mechanical) would not allow those actuators to move beyond certain minimum and maximum set points for each line that they service.
The people that designed these systems were anything but stupid and it is failsafes layered on more failsafes, the big killer for systems like this is a very simple one: back maintenance.
Unlikely.
> but it's likely that gas main pressure is controlled by a computer.
But the failsafes are not. Overpressure is something the system is designed to handle, and those gas substations that you see every now and then in fields are the places where the overpressure regulation devices are located, and they are purely mechanical.
> It'd be shocking if a software failure could cause dozens of fires.
It would be, but this isn't that. The actuators on these systems are made with the express purpose that line fluctuations will always be slow enough to catch up with. But if a regulator fails in a bad way that might cause a prolonged overpressure with the initial change arriving as a spike, which may expose further weaknesses downstream.
So the signature of an upstream regulator failure (a big one, and a sudden one too), is fairly consistent with what you are seeing here. The software actuators would not cause a pressure rise fast enough for that initial spike and the limit settings on those actuators (which are mechanical) would not allow those actuators to move beyond certain minimum and maximum set points for each line that they service.
The people that designed these systems were anything but stupid and it is failsafes layered on more failsafes, the big killer for systems like this is a very simple one: back maintenance.