One System for All Oil Related Tasks
The Allen AOC Series Oil Conditioner is a vacuum distillation system that is used by several major manufacturers during the last phase of the building or repair of large power transformers, the testing phase.
In this part of the process, the Allen Oil Conditioner fulfills the multiple tasks that consist of moving large quantities of test oil from the test oil tank to the new transformer and, after completion of the test, return the oil to the test oil tank. This allows the same batch of oil to be used almost indefinitely because the Allen Oil Conditioner keeps purifying the oil throughout this process.
New or Repaired Transformer Testing
The working fluid in transformer manufacture is insulating oil. It is used to immerse the newly manufactured transformer winding and core assembly in the tank which is then filled with oil. The oil is used for insulating purposes and for the dissipation of generated heat from the windings. The assembly of the windings on the core allows gaps to improve the oil circulation around the windings. The tank is constructed with fins to allow better circulation of the oil and to provide a greater surface area for contact with the cooling air. Very large transformers have banks of cooling fans to provide forced-air cooling which are coupled to thermostats. Some transformers have a pumped oil circulation system and an oil cooling circuit as well.
Prior to final testing, the assembled core and windings are heated to between 850 and 1200 °C for a certain length of time. This sometimes takes a few weeks for large transformers. The windings are considered dry when the values of power factor drop to a minimum and the insulation resistance increases rapidly. Before the final tests, the transformer is left to stand for several days to let any remaining air bubbles dissipate into the oil. The final tests usually include ratio, polarity, resistance, and tap changer operation tests. The test oil is then pumped out of the transformer tank, returned to the test oil storage tank, and stored for future use.
Process Optimization with an Allen Transformer Oil Conditioner
Filling the new transformer: Using the Allen Oil Conditioner's inlet pump, the test oil is first purified and, using the outlet pump of the oil conditioner, is pumped into the new transformer. This insures that clean, dry, and uncontaminated oil enters the new transformer.
Emptying the new transformer: Using the Allen Oil Conditioner’s inlet pump, the oil is once again pumped through the system and purified before the oil is returned to the test oil storage tank by the system discharge pump. If desired, the oil conditioner can be bypassed and the oil can be returned directly to the test oil tank via the Allen Oil Conditioner suction and discharge pump.
The manifold and valves for this process are incorporated in the oil conditioner design. The entire operation can be fully automated by the on-board programmable logic controller (PLC), which can control electrically-actuated valves in a programmed sequence.
The optional Allen Remote Monitoring System (ARMS) designed by our Allen IT specialists can facilitate monitoring from a central control room with one computer screen and a tie-in via the Internet. ARMS also allows monitoring of the entire process via a cellular telephone.
