3 ms·

Oof. The report from the steam turbine operator is dicey. Their time stamps are relative so they don’t have GPS time synced but they are ms precision so must ha

Oof. The report from the steam turbine operator is dicey. Their time stamps are relative so they don’t have GPS time synced but they are ms precision so must have a decent sequence of events record. But they don’t know why the 200MW steam turbine unit tripped, which causes a knock on trip of 400 MW of gas turbines. Report says steam turbine tripped due to a discrepancy in the speed signals. Will be interesting to see what that is! The turbine speed will be measured either by number or teeth passing by a magnetic pickup or proximity sensor per unit of time but unit of time varies so it is always a whole number of teeth, or measuring the period of the generator voltage waveform is also a nice speed signal, but maybe not if you are trying to ride through a fault in which the voltage has collapsed or is subject up to bad harmonics. Maybe harmonics caused an instantaneous over speed trip in the turbine governor? Protection relays wouldn’t be involved in measuring turbine speee and should be smart enough not to trip on overfrequency in harmonics during a fault.

repolfx 7y ago
Yeah I found that part the most concerning. Basically RWE don't have any clue why they tripped even more than a month on from the event, and apparently have to wait for their next scheduled outage to make progress? That's not good. There also seem to be multiple faults at once that they don't know anything about. Turbine trip? No clue, could be bad sensors, could have been some actual physical problem in the turbine. Overpressure in the condenser? No clue, could be anything. Second generator tripped? Dunno boss. Implies that don't have enough sensor coverage and are hoping to literally eyeball something wrong when they next open it up. Also implies they can't shut down their own plant to diagnose apparent faults in anything like a reasonable timeframe? Not good. Also worth noting - Newcastle Airport were totally fine on their UPS but demanded to be considered a priority customer anyway, and that request was granted? Why? They clearly don't need to be, they have a working UPS! Honestly I'd be sending this report back for more work if I were the boss guy receiving it. It's not good. Filled with repetition, bad grammar, missing information (why did London Underground shut down, what was this 'internal traction issue') and most seriously it leaves a gaping hole around Little Barford.
- michaelt 7y ago
  They clearly don't need to be, they have a working UPS! The impression I get from the data centre outages reported here on HN is that backup generators are about the least reliable thing in IT.
  - repolfx 7y ago
    Yeah, but most places don't have UPS at all. If Newcastle Airport can survive a power outage but other places cannot, why should it be prioritised?
    - michaelt 7y ago
      Because the airport's UPS+Generator is only, say, 99% effective. And a 1% chance of losing power to air traffic control and runway lights is worse than a 100% chance of 1000 homes having their dinner spoiled by the cooker turning off.
  - cesarb 7y ago
    > backup generators are about the least reliable thing in IT. Not just in IT, as the Badim Hospital fire (with 11 dead and IIRC over 70 wounded) two days ago shows.

repolfx 7y ago

Yeah I found that part the most concerning. Basically RWE don't have any clue why they tripped even more than a month on from the event, and apparently have to wait for their next scheduled outage to make progress? That's not good. There also seem to be multiple faults at once that they don't know anything about. Turbine trip? No clue, could be bad sensors, could have been some actual physical problem in the turbine. Overpressure in the condenser? No clue, could be anything. Second generator tripped? Dunno boss. Implies that don't have enough sensor coverage and are hoping to literally eyeball something wrong when they next open it up. Also implies they can't shut down their own plant to diagnose apparent faults in anything like a reasonable timeframe? Not good. Also worth noting - Newcastle Airport were totally fine on their UPS but demanded to be considered a priority customer anyway, and that request was granted? Why? They clearly don't need to be, they have a working UPS! Honestly I'd be sending this report back for more work if I were the boss guy receiving it. It's not good. Filled with repetition, bad grammar, missing information (why did London Underground shut down, what was this 'internal traction issue') and most seriously it leaves a gaping hole around Little Barford.

michaelt 7y ago
They clearly don't need to be, they have a working UPS! The impression I get from the data centre outages reported here on HN is that backup generators are about the least reliable thing in IT.
- repolfx 7y ago
  Yeah, but most places don't have UPS at all. If Newcastle Airport can survive a power outage but other places cannot, why should it be prioritised?
  - michaelt 7y ago
    Because the airport's UPS+Generator is only, say, 99% effective. And a 1% chance of losing power to air traffic control and runway lights is worse than a 100% chance of 1000 homes having their dinner spoiled by the cooker turning off.
- cesarb 7y ago
  > backup generators are about the least reliable thing in IT. Not just in IT, as the Badim Hospital fire (with 11 dead and IIRC over 70 wounded) two days ago shows.