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I rgink that a recloser is a circuit breaker that opeates with cysles OPEN-CLOSE O-C-O, e.g. when a fault appears the recloser opens, then it tries to close , if the fault is not there it remains closed, if th faults still exists makes another cycle and finally trips open. It is used in overhead...

On site , a CCPP with a steam turbine Franco Tossi Mechanica and Siemens ORSI IT control system we experience lateley the following event: WHile ST runs her start up sequence the speed is controlled by HP Stop (throttle) valve). After the spped of 2800 rpm the conmtrol of spped goes to HP...

This week we made the tap cahnger inspection, it was almost new, no sign of overheating or whatever else. Seems we have to reconsider the need for gas analysis.

The repalcement of cross fire tubes did not solve the problem of vibrations.

an isoaltin and earthing, we lokked and found air on the bucholz relay of tap chager compartment, also there was air when we vented. But the oil (probably due to the filter ) was almost clear.

isquaredr , The diverter switch is not separate from the tap changer, is separate from the main oil tank.

subtech , the oil was new, not from another transformer but from new drums. prc, i mean oil from the tap changer diverter switch tank. THe BDV is very good, 60kV and higher. defreitas, I have not seen any carbon in the oil. BUT during the first 30 months of transformer operation there was no...

Last week we made a repalcement of the piping ofcross fire tubes , all the flanges on these tubes were in very bad wuality. After these works the comaprtment temperatures dropped from 180 to 115 degrees Celsius.

The results from the oil sampling show very good dieelctric strength but increased concentration of gases. Find below the resutls from two concequtive sampling Hydrogen(H2) (ppm,w) 3414 25075 Oxygen(O2)(ppm,w) 8492 7452 Nitrogen(N2) (ppm,w) 120665 35969 Carbon monoxide (CO)(ppm,w) 14 148 Carbon...

roydm, thanky you very much for your post, we use on site the three element level control. And it works OK, during ent big outage we will combine the revision of the transmitters span as well.

On site we have one Ge generator 325MVA 4-pole hydrogen cooled with static excitation system EX2100. We experience alarm code 53 fault, and M1 controller reads different current magnitude than M2 so it goes to transer block and we loose redundancy. There is a product bulletin from GE that says...

edison123 , we made work on the spring contacts of the diverter switch.

On site we have a three winding step up transformer 440MVA, 400kV/15.75kV/15kV. Lately we made maintenacne on the tap changer (MR), changed the oil and put back in service. After 10 days we made ne oil analysis and after 40 days we made a second oil analysis. The results of the first analysis...

hacksaw unfortunately the sight gauges are not working correctly and we are in the process to repalce them

Our HRSG is a triple pressure one with an HP Drum that works at pressure of 115 bar at base load of gast turbine. During recent overhaul we saw that the actual level of the drum (red marks on the inside of the level drum) is almost 100 mm higher than the designed one. THe level is measured with...

On site we have 10 cooling tower fans, driven through eelctric motors , long shaft and gear box. We have experienced two issues upt o now, after 3 years of operation: 1) Ringing on the gears of the gearboxes, the most probable cause is the direct on line start of the motors 2) During summer...

Becasue when i have a load rejection with the turbine loaded to 110 MW until 140MW(140 MW is the base load) i get an overspeed. The control scheme and the vlaves (steam supply and bypass) cannot tkae the load rejection and also the turbine is uncapable of staying to FSNL after the...

byrdj, now we have concentrated on the load compartment enclosure wit the cooling fans capacity and the damper backdraft orientation. Although, it is a 9F turbine, where the loead shaft compartment is fillowed by air intake and then by turbine. I will give you the final data of troubleshooting.

The turbine finally trips from cross trip from DCS BUT this comes 2-3 sec after the breaker open, so gine with the breaker open and 3 sec to still feeed steam to the tubiwill finally overspeed. I was thinking maybe on control scheme to calculate accelearation by simulating a load loss and hence...

The last RSO showed perfect condition. The actual problems we had were cross fire tubes hot air leaks inside turbine compartment. These leaks led to thermal expansion of the turbine and change of place of the generator. The vibrations were characterized as subsynchronous. Gap increases during...