Recent content by GamezBeCJ

Bucholz relays have 3 alarms/trips. The first is accumulation of gases (usually set to 150 mm^3), the second one is total absence of oil in the Bucholz gas accumulation chamber (that means the conservator is out of oil) and the third one is the oil speed, even when the Bucholz is full of oil...

There is no noticeable change in losses due to aging.

Electripete: Do you have to service all pumps and fans at once?, can you do one by one?. You could de-energize one device at a time, try to reduce the load on the transformer to the minimum possible and keep an eye on winding temperature indicator. If you do this during winter time, it is even...

Hidalgo: You could simply install a 25kV polimeric insulator between the lines. They would work well for your situation.

One more thing. As it has been sugested before. Contacting the manufacturer is a very good idea. He has all the calculations and models needed to predict the cooling capacity of the tank alone, and would give you a much more accurate estimate.

Eletripete: Sorry it took so long. Usually in America you will se transformers with that kind of cooling (OFAF or ODAF) starting from 100 MVA up to 500 MVA. The half hour I mentioned is a little bit conservative, since this is considering that the top oil rise is at is rated value (say 65...

Electripete: The trasnformer manufacturing company that I work for would allow a maximum half our of operating at full load after losing all the cooling system (fans and pumps). This applies only to a transformer without ONAN rating. The unit in this case is designed to constantly have oil...

Also you want to be sure you are not overexciting the transformer.

If what you are talking about is Winding or Copper Losses, you do not need the X-Y losses because they are acounted for in the H-X and H-Y tests.

Cayjay: Power transformers usually have two or three ratings. A first power rating named ONAN (Oil as the cooling medium inside the transformer working by natural convection AND air as the outside cooling medium working by natural convection). Second and third stages usually involve the use of...

You can do a sonic scan, usually you would use an ultra-frequency sensor and trace the magnitudes around the transformer. The partial discharges will make the readings go high in the area where they are ocurring. I have used this method to successfully pinpoint where the partial discharges are...

mrbj: I would use the following procedure: 1) You have to calculate three things for the transformer: Magnetization Curve, Damage Curve and the Maximum Short Circuit Current. 2) The magnetization curve is: 25 times the rated current (High or Low Side, depending what are you...

My idea is this. I don't know if you have seen how the computer circuit in a car is built. In that case the whole circuit board and components are embeded in a plastic. I'm sure you can find a suitable/compatible (nitrile?, viton?, noprene?) material where you can embed the TC circuit in...

Hi GENELEC: My opinion is: 1) I agree with rraghunath. It is more likely that the cable termination was the problem. If the oil container was the problem, it would mean that either the design clearances were wrong or the oil quality was very poor. 2) Also, I would have not energized after the...

Hello everyone: I'm looking for a good reference (book, website, manufacturer manual) regarding Cooling Fan design. Currently I'm in charge of redesigning an old line of these devices. Any help is always greatly appreciated.