"Strategy without tactics is the slow route to victory. Tactics without strategy is the noise before defeat." - Sun Tzu
More outage images, with additional commentary to follow soon.
Below: The generator terminal enclosure, disconnected from the isolated phase bus. The combination of high electrical current and high voltage requires each phase of the generator have its own enclosure until it reaches the transformers. The potential transformers (PTs) for metering and control are just left of the guy's head. Note the temporary grounding wires.
Below: The braids that normally connect the generator to the isophase bus.
Below: Photos of the steam turbine prior to disassembly, from either side. In the second image some of the interference has been removed. Orange indicates FME - Foreign Material Exclusion barriers.
Below: The condenser waterbox. This condenser has a vertical entry manway on one end, so it's necessary to use a safety harness and a retrieval mechanism to enter the space.
Below: Looking down inside the above manway, you have a view of the tubesheet inside the waterbox prior to cleaning. Bits of cooling tower, plant matter, and critters all pressed into the tubes. We will be shooting brushes through each tube this outage with compressed air. No big deal, there are only eight thousand tubes to clean. LOL.
Below: The grating that keeps you from falling down the pipe into an underground line filled with muddy water and drowning - which is why we have a safety harness and a retrieval mechanism - just in case.
Below: Steam turbine #2 journal bearing and thrust bearings left and right. The Intermediate Pressure steam turbine casing is to the right, and the High Pressure casing is to the left.
Below: One of the upper bearing caps. Clearly there has been a bit of scuffing on a couple of the tilting pads.
Below: The #1 journal bearing. This one sits in the turbine exhaust, surrounded by steam - in a bearing enclosure of course. The millwrights have been taking "as-found" run out and thrust measurements, as there is a dial indicator mounted on a magnetic base atop the bearing. The wires are for monitoring the bearing metal temperature while the machine is in service.
Below: The final rotating stage of the steam turbine before it exhausts into the main condenser.
At the other end of the machine, the generator is being prepared for removal of the rotor, AKA the "field".
Below: The end of the rotor is resting on a temporary block had been installed after the lower bearing was removed. Prior to removal the cable will be tightened up, and a skid plate will be installed underneath the rotor. The rotor will be supported at this end, and the other end will slid along the skid plate.This is a brushless exciter, so you can see the diode wheel at the very end with the heat sinks. The section that has paper and tape is a smaller generator called a main exciter.
Below: The frought and delicate business of getting the upper turbine shell off the lower shell. The bolts are left hanging through their holes to maintain alignment - to prevent it from twisting as it lifts off the turbine rotor. Each corner is jacked up with hydraulic presses half an inch at a time. The lift is a "critical lift" and the process is very slow and methodical. There will be several more of these coming up.
Below: The High Pressure upper shell with the diaphragms still pinned in place.
Below: Racks for storing the diaphragms once they are removed from the shell.
Below: High pressure turbine casing, lowered to the ground floor from the turbine deck.
Below: The high pressure steam turbine rotor and lower casing. The second stage shroud seal appears to have been rubbing. To me this looks like a fresh rub. This was likely during turning gear operation while cooling down with the insulation removed causing shell distortion. It's hard to believe that this rub would not have worn off after years of operation if the seal was improperly installed.
One good thing is there doesn't seem to be any steam cutting at the casing split, so we haven't got any damage there, and same with the diaphragms. With any luck, there won't be a lot of shell repairs. Time will tell and the engineers should have some answers soon!
No comments:
Post a Comment