3 ms·
> rail companies not paying attention to actual grid specs I would give the rail companies a little slack. They did specify trains that should have handled the
by avianlyric 7y ago
> rail companies not paying attention to actual grid specs
I would give the rail companies a little slack. They did specify trains that should have handled the frequency change. But Siemens didn’t build the trains to spec.
The shutdown was unexpected and entirely down to Siemens not building their power supplies the specs set out by the rail company.
- growse 7y agoThis isn't accurate. Siemens delivered trains that could tolerate the power fluctuations at the time they were specified. The problem was that the national grid then changed (loosened) the specification of what an acceptable fluctuation was. The trains could not tolerate this new specification. What we can blame Siemens for is not providing an easier and quicker way to get the electrical systems back on their feet after a problem, instead relying on a specialist to physically visit a stranded train. I think they said they'd fix that one...
- makomk 7y agoThat's not true - the frequency spec hasn't changed in any way relevant to what happened. (I think there was some changes to rate-of-change-of-frequency disconnect specs for generators and possibly medium-term frequency accuracy, but neither of those things mattered here.) This kind of near-simultaneous failure of two large generators, tripping the low frequency demand disconnect, was always specified to cause a dip in frequency of a level those Siemens trains couldn't cope with. There was actually a very similar failure back in 2008. The only reason that didn't cause such chaos is because those trains hadn't been ordered yet.