The root cause report is written to completely protect the engineroom staff by omitting them from it. Where is the human element included in it? I CALL BULLSHIT![/QUOTE]
The idea that all parties involved are conspiring to protect the crew is ludicrous. What on earth would motivate the USCG, NTSB, the engineering consultants, the WSF and the other crew members to all conspire to protect a member of the crew? The dawning of the age of Aquarius perhaps, christian love for their fellow man? Bullshit. I’ve never witness the slightest hesitation on anyone part to blame the crew. In fact some are downright gleeful to do it.
I highly doubt that anyone involved here has demonstrated the slightest hesitation or reluctance to blame the crew.
BTW, I don’t know jack shit about the control systems of these diesel electric propulsions plants and neither do you.
I know plenty and yet in your denouncement, you offer nothing to disprove my claim that some manual intervention took place shortly after 12:31. The vessel was on the #1 generator at that time and enroute to dock in Winslow shortly. What would an engineer have done if #3 and #4 diesels were still running? The record does not show them shutting down nor would one expect them to. I say some layabout boob put them back online by closing the breakers again and ZAP…POOF! And we still don’t know why the ship went black if it had two busses…why didn’t the tie breakers work and protect the other switchboard? Should have been able to limp the vessel back to the dock on the undamaged board and the #1 & #2 generators even if it meant switching to the screw at the opposite end…HMMM?
btw, plenty of reasons to protect the crew…the whole rotten system is rife with cozy friendships between management and vessel staff. Besides, it looks oh so much better if you can blame it on something supposedly out of the hands of mortal man, like GOD! THERE IS NO INCOMPETENCE IN THE SYSTEM AND IT WAS GOD HIMSELF WHO SMOTE THE TACOMA THAT FATEFUL DAY!
besides this is not a USCG incident report but one paid for by the WSF. Where is the USCG on this…this was a serious marine incident involving a passenger vessel, I’d hope they will be issuing a report to the public? That one will take on the human element so glaringly omitted from this whitewash!
My understanding is the failure involved automated controls:
When an offline generator is put online, a synchronizer relay compares generator’s phase angle and voltage magnitude against the rest of the system and if the difference is within the set tolerance value, it commands the PLC to close the breaker and make the generator part of the system.
Because of the nature of the failure a PLC received signals that the system was OK and automatically closed a breaker that should not have closed given the nature of the damage.
[QUOTE=Kennebec Captain;147982]My understanding is the failure involved automated controls:
Because of the nature of the failure a PLC received signals that the system was OK and automatically closed a breaker that should not have closed given the nature of the damage.[/QUOTE]
ain’t buying that the breakers to #3 or #4 generator reconnected automatically after both tripped at 12:31:01…I say it was done manually because the TACOMA was about to enter Eagle Harbor and three gensets needed to be connected for a docking.
[QUOTE=c.captain;147998]ain’t buying that the breakers to #3 or #4 generator reconnected automatically after both tripped at 12:31:01…I say it was done manually because the TACOMA was about to enter Eagle Harbor and three gensets needed to be connected for a docking.[/QUOTE]
Yes, the watch attempted to put an extra generator on-line IAW SOP. However the system had suffered undetected damage at shutdown and when the crew attempted to use the extra generator later the automation should have made it impossible to put it on line.
no, they tried that and it tripped off #4 and then one second later #3 breakers…the blow up occurred some indeterminate time afterward…I say it was when they tried yet again to connect generators who’s breakers were already badly compromised because of what happened back at the Seattle dock.
WTF happened after both breakers tripped off? If they tripped then the buss should have been protected…that is what circuit breakers do![/QUOTE]
Obviously you are not familiar with IEEE.C62.48 [2];
According to IEEE.C62.48 [2], temporary over-voltage can be caused when a distribution generator and part of the distribution network are separated.
A generator and the network are separated when a breaker is open. This creates a over-voltage. This energy created by the over-voltage is absorbed by surge limiters but in this case, because the surge limiters were worn out they did not absorb the over-voltage and the equivalent of a lightning strike passed between # 4 and # 3 frying everything in it’s path.
To limit over-voltage in the 4.16KV system, surge limiters are installed on all generator and feeder cubicles. These surge limiters are designed to have an average
life span equivalent to that of the electrical installation they protect, but they progressively deteriorate over time due to the successive over-voltage they eliminate.
During faults, generators keep injecting power into the system and the arresters on generators need higher energy discharge capacity.
My guess the reason the time is not known is because the data logger got fried and stopped recording the times. It’s not some “18 minute gap” with crew shenanigan.
according to the timeline generator #1 was still running and connected after the breakers for gens #3 and #4 tripped plus the control circuitry for gens #1 and #2 were in a whole separate switchboard including there being two buss tie breakers between the #1 and #2 switchboards which should have provided generation/propulsion redundancy yet the ship goes DIW and nothing the engineers do can restore any current at all to the propulsion motors at either end? Supposedly, the generators and their engines were not damaged nor any of the propulsion motors nor the #1 switchboard yet the vessel could not return to the dock in Winslow? REALLY?
the arc flash that occurred in the #4 breaker cabinet should not have shut the TACOMA down dead in the water. Something else happened that this report from Siemens is trying to bury but if you read between the lines this could never have been a pure electrical equipment failure but has to have been precipitated by human intervention that started a cascade of even more massive failures.
besides, how on earth does a smoked breaker cabinet or two result in $1.8M in damage? I can barely see $180k in destroyed wiring/equipment. Here is a list of all the damaged equipment on the TACOMA from the report. Can anyone see $1.8M here?
[I]“The breaker should not have been allowed to close[/I]” implies that someone commanded the breaker to close.
The automation that was in place to prevent a WSF placeholder from hurting himself or the machinery obviously failed and the system did what all the other parts of the system tried to warn the “engineer” would happen … it detonated.
Someone seems to have forgotten one of the first rules of a plant going downhill … don’t just DO something … stand there for a moment and figure out what is going on.
ok, I am going to put forth another theory which is that the damage to the TACOMA was inn fact, NOT catastrophic which is indicated by the report but that operator incompetence was why the TACOMA was not able to limp back to Winslow and that now the WSF sees a nice way to soak the State’s fund for emergencies to get their hands on all that cash that they wouldn’t be able to without all the smoke (pun intended) and mirrors provided by this report. INCOMPETENCE AND CORRUPTION COMBINED TOGETHER INTO A PERFECT STORM OF A FAILED GOVERNMENT RUN OPERATION!
It was a PLC that closed the breaker. The PLC logic did not anticipate all possible combinations of blown fuses in the control system and got “fooled” by the particular combination that occurred. With any blown fuses the PLC shouldn’t have allowed the breaker to close, the error was made when the PLC was programed.
When an offline generator is put online, a synchronizer relay compares generator’s phase angle and voltage magnitude against the rest of the system and if the difference is within the set tolerance value, it commands the PLC to close the breaker and make the generator part of the system.
[QUOTE=Kennebec Captain;148045]It was a PLC that closed the breaker. The PLC logic did not anticipate all possible combinations of blown fuses in the control system and got “fooled” by the particular combination that occurred. With any blown fuses the PLC shouldn’t have allowed the breaker to close, the error was made when the PLC was programed.[/QUOTE]
it is a very sophisticated power management system that can start and then connect generators fully automatically based on demand and maintaining spinning reserves. $700M drillships have such systems but I seriously doubt TACOMA does. Besides, few engineers trust power management and most all chose to start generators and connect them manually. There is nothing in the report which indicates auto start and auto connection of the generators was used on the vessel so it by all shapes of logic required someone to manually do this and it was only the failure of embedded safety interlocks which allowed the manual connection to be attempted with the obvious cascade of failures which happened shortly afterward.
[QUOTE=Kennebec Captain;148045]It was a PLC that closed the breaker. The PLC logic did not anticipate all possible combinations of blown fuses in the control system and got “fooled” by the particular combination that occurred. With any blown fuses the PLC shouldn’t have allowed the breaker to close, the error was made when the PLC was programed.[/QUOTE]
“When an offline generator is put online, a synchronizer relay compares generator’s phase angle and voltage magnitude against the rest of the system and if the difference is within the set tolerance value, it commands the PLC …”
That says very clearly that the generator was commanded to go online … an engineer pushed the button to start the generator breaker closure sequence, to “put it online”. A PLC does not make the initial decision to do anything, it responds to a command input, in the is case a command to place the generator online in spite of a series of warnings that should have indicated such an action might not be a good idea.
[QUOTE=Steamer;148056]“When an offline generator is put online, a synchronizer relay compares generator’s phase angle and voltage magnitude against the rest of the system and if the difference is within the set tolerance value, it commands the PLC …”
That says very clearly that the generator was commanded to go online … an engineer pushed the button to start the generator breaker closure sequence, to “put it online”. A PLC does not make the initial decision to do anything, it responds to a command input, in the is case a command to place the generator online in spite of a series of warnings that should have indicated such an action might not be a good idea.[/QUOTE]
If my reading of the report is correct, the damage to the control circuits, two blown fuses at least, occurred when the generator was routinely taken off-line. The only indication of damage was a high voltage alarm which was acknowledge by the operator. When the generator was put back on line by the watch, evidently also a routine procedure, the second sequence of events occurred which led to the flashover.
The watch was putting the generator on-line, this is not in dispute, nothing in the report indicates that it wasn’t 100% routine. Nothing is said about how the generator is started and warmed up etc but there is no reason to assume auto-start. As far as actually physically closing the breaker to connect the generator this is what we know:
When an offline generator is put online, a synchronizer relay compares generator’s phase angle and voltage magnitude against the rest of the system and if the difference is within the set tolerance value, it commands the PLC to close the breaker and make the generator part of the system.
The signals to the PLC should have disallowed the connection but because of the two blown fuses, a situation not anticipated in the logic of the PLC it " allowed" the breaker to close. This was subject to a great deal of testing on the other ferries according to the report. Had either one or three fuses blown the PLC would not have closed the breaker.
The generators tripped out about a second after the connection was made. The flashover was probably a split second later.
fine then but not one thing here explains to me why the TACOMA could not get propulsion back. only one switchboard was damaged and NOTHING else! WHY DID IT NEED TO BE TOWED?
if this is not an error of incompetency resulting in the incident then it is incompetency in what was done afterwards!
On our system you can manually initiate at the HMI, the switchboard remote operator and of course the close button on the breaker itself. HMI uses the systems synch function and you just sit there and watch it do its job. If you go local at the board you will have to manually synch and press the button to close the breaker. In both of those instances the PMS Logic will not allow the breaker to close if there is any problems in the system. I was told that if you choose to remove the cover plate over the breaker button and push it manually to close the breaker you override all safety features. It was explained to me to do it with a broom stick and cup your balls at the same time.
I am convinced now that there is a scam going on here…$1.8M to fix this? TOO FUCKING MUCH! Siemens and WSF was defrauding the taxpayers of the State of Washington and a bunch of bananas otherwise known as the engineroom staff of the TACOMA are being protected!
[QUOTE=c.captain;147956]hardly…the WSF engineers are little smarter than any GoM engineer when it comes to diesel electric power management. The entire report completely fails to discuss a human element as if the entire propulsion system on the TACOMA was designed to operate fully automatically without any manual intervention.
You tell me, if breakers open then a generator is no longer producing current…correct? The breakers for generators #4 and then #3 opened at 12:31:01 but a flashover still occurred…why if the breakers were open? Did someone manually close the breakers again? They must have and that is the moment when everything went poof. Also the report says that generator #1 remained connected, why would the ship go black at that point…it wouldn’t…would it? WHAT THE F#@$ HAPPENED IN THE TIME BETWEEN 12:31 AND THAT UNDETERMINED MOMENT THAT THE SHIT EXPLODED IN ONE HUGE ARC FLASH?
Also, it must be mentioned that the report states that TACOMA has a split buss arrangement with gens #1 & #2 one one buss and #3 & #4 on a second. Even if the tie breakers did not open, how on earth did the ship go black after the breakers for gens #3 & #4 opened or that later arc flash occurred? Gen #1 was still connected according to the report…when did the second buss become lost and how?
The root cause report is written to completely protect the engineroom staff by omitting them from it. Where is the human element included in it? I CALL BULLSHIT![/QUOTE]
I think you’re reading way too into it. I interpret the “exact time unknown” that the arc flash occurred as meaning that no one knows down to the exact second when it happened. It is logical to assume it occurred as/right after the Gen 4 breaker was closed (the breaker did indeed close, if for just a millisecond because if it hadn’t, we wouldn’t be talking about this). All (most) of the time-stamped data is pulled from the alarm and monitoring history. The arc flash itself, obviously, would not be on there. These breakers and panels are not in the ECR, such as they would be on a typical ship. I doubt anyone actually witnessed it. The generators on these boats are started and put online/offline remotely in the ECR with the click of a mouse.
No engineer with even 1/4 of a brain would manually push closed a breaker like that in this kind of situation after the automation had already rejected it. If they did, and somehow managed to not injure themselves, then MAJOR heads need to roll.
As for the split buss, the boat did have some very limited propulsion on one end only (probably the end opposite the #3-4 generators). I saw this firsthand as I happened to be in Eagle Harbor that day and as the Foss boats shifted the Tacoma from the main terminal to the yard, there was definite prop wash coming out of the forward end of the boat.
[QUOTE=Kennebec Captain;148062]The watch was putting the generator on-line, this is not in dispute, nothing in the report indicates that it wasn’t 100% routine.[/QUOTE]
But what is missing is emphasis on the fact that the initial damage was done when the generator was taken offline after departing Seattle. There were high voltage alarms, blown fuses, and possible burning of the surge limiters. There is no record of anyone responding to this warning in any manner other than acknowledging the alarm. Apparently no one bothered to check the phase voltages after that event or before attempting to place the generator online for the arrival. One would expect at least a minor interest in the circumstances that lead to the alarm. I know there isn’t much time to finish the sports page on that run between departures and arrivals but, geez, it doesn’t take all that long to rotate a voltmeter switch.
