Importance and Types of Transformer Cooling Systems
The strain that a transformer carries without heat damage can be increased by using an adequate air conditioning. This is due to the fact that a transformer's loading capacity is partly decided by being able to dissipate heat. If your winding hot spot temperature reaches critical levels, the extra heat can cause
the transformer to fail prematurely by accelerating aging of the transformer's insulation.
A air conditioning system increases the load capacity of a transformer by improving its capability to dissipate the heat generated by electric energy. In other words, good cooling systems allow a transformer to handle more of a load pc otherwise could without reaching critical hot spot temperatures.
One of the more common kinds of transformer cooling equipment is auxiliary fans. It may be used to keep the radiator tubes cool, thereby increasing the transformer's ratings. Fans really should not be used constantly, but rather only when temperatures are such that extra cooling is required. Automatic controls can be set up so that fans are switched on when the transformer's oil or winding temperature grows too much.
Maintenance of Cooling Systems
* Dry-Type Transformers:For dry-type transformers, the area in which the transformer is to be installed needs to have proper ventilation. This ventilation ought to be checked prior to installation to make certain it is adequate. Additionally, the transformer's radiator vents must be kept clear of obstructions
that may impede heat dissipation.
* Forced Air: If the transformer's temperature is being kept at acceptable levels by forced air from the fan, the fan's motors ought to be checked periodically to be sure they are properly lubricated and operate well. The thermostat that ensures the motors are activated inside preset temperature ranges ought to be tested as well.
* Water cooled systems: Systems that are cooled by water ought to be tested periodically to make certain they operate properly and do not leak. Leaks can be checked by raising the stress within the cooling system, which is often done in various ways. In the event the cooling coils can be taken off from the transformer, internal pressure is true by adding water. Otherwise, pressure checks may also be made using air or coolant oil, if your coils need to be checked inside transformer itself.
If the cooling coils are removed from the transformer, the water air conditioning system as a whole can be tested. Here, the coils are full of water until the pressure reaches 80 to 100 psi, and left under that pressure for about an hour. Any drop in pressure could be a indication of a leak. Another
equipment linked to a water-cooled system may be tested at the same time, for example the alarm system, water pump and pressure gauges. Also, the water source should be tested to ensure it has sufficient flow and pressure.
*Liquid coolants: When oil coolants are ready they are dehydrated, and processed to get free of acids, alkalis, and sulfur. They must also have a low viscosity when they are to circulate easily. If your transformer is cooled by oil, the dielectric strength of the oil should always be tested prior to the
transformer is put into service.
Types of Cooling Systems
For oil immersed transformers, the variety of cooling systems are as follows:
* Oil Immersed Natural Cooled (ONAN): Here, the core and the windings are kept immersed in oil. The transformer is cooled from the natural circulation on this oil. Additional cooling can be provided by radiators, which improve the surface area over which a substantial transformer can dissipate heat.
Kinds of Cooling Systems
* Oil Immersed Natural Cooled
* Oil Immersed Air Blast
* Oil Immersed Water Cooled
* Forced Oil Air Blast Cooled
* Forced Oil Natural Air Cooled
* Forced Oil Water Cooled
* Forced Directed Oil and compelled Air Cooling
* Oil Immersed Air Blast (ONAF): In this case air is circulated and also the transformer cooled with the help of fans. Fans allow someone to have a smaller transformer for any given rating, since less surface area is needed for heat dissipation. This in turn can cut costs.
* Oil Immersed Water Cooled (ONWN): Here the transformer is cooled by an inside coil through which water flows. This process is feasible so long as there exists a readily available source of a substantial amount of water, which is not always the case. This kind of cooling is becoming less common in recent years, abandoned for Forced Oil Water Cooled (OFWF).
* Forced Oil Air Blast Cooled (OFAF): In this case, cooling is accomplished in two ways. Oil circulation is facilitated with a pump, and fans are combined with the radiators to supply blasts of air.
* Forced Oil Natural Air Cooled (OFAN): Because of this type of cooling, a pump is protected within the oil circuit to aid in oil circulation.
*Forced Oil Water Cooled (OFWF): Here, a pump within the oil circuit forces the oil to flow out through a separate heat exchanger in which water flows.
The most dependable type of cooling system for any transformer is the oil-immersed naturally cooled (ONAN), which also produces the least noise. A forced-air cooled transformer (OFAF) is more efficient, but it is also noisier much less reliable on account of the potential for fan malfunction.
The method of forced cooling has been used for many years now to improve the loading capacities of transformers. A transformer's thermal performance may be directly improved from the implementation of cooling systems. Consequently, it feels right to avoid excess heating and accelerated aging in a transformer by using the appropriate air conditioning system.