How power transformers are cooled
Summer is not only a time of vacations, but also the hottest time for all power engineers. After all, the scorching sun heats not only the surrounding air and sea, but also the power units located at the substations are heated.
And in order for the power transformer to function for a long time and trouble-free, it is necessary to strictly monitor its temperature.
In this article, I will tell you how this temperature control is carried out for different types of transformers.
Existing types of transformer cooling
There are several options for cooling power transformers and autotransformers. And what type is used on one or another transformer directly depends on the power. Let's take a closer look at each type of cooling.
Cooling type С, СГ, СЗ, СД
If the letter "C" is present in the letter designation of the power transformer, it means that the transformer is dry version - special oil is not used.
In this embodiment, the windings and the magnetic circuit are air-cooled. This type of cooling is mainly used for transformers up to 1.6 MV * A.
The following modifications exist:
- SG - sealed housing;
- SZ - additionally protected case;
- СД - there is a forced circulation of air masses on the transformer case.
Cooling type "M"
Higher power transformers need a much more efficient oil system. Thanks to oil, cooling is much more efficient.
This type of cooling is characterized by the presence of special pipes and fins on the body, through which the natural circulation of oil takes place.
This type of cooling is used in transformers and autotransformers up to 16 MV * A.
Cooling type "D"
In this type of cooling, in addition to oil cooling of natural circulation, fans are also installed, which additionally cool the oil in the cooling pipes.
In this case, the blowing is turned on only when the oil temperature reaches 55 degrees Celsius.
This type of cooling is applicable for transformers with a capacity of 16 to 80 MV * A
Cooling type DC, NDC
In the DC system, in addition to fans that blow air over oil coolers, there are also oil pumps, which force the oil to circulate through the cooling system.
This type of cooling made it possible to move away from the traditional approach in building power transformers, and in such a system, the transformer tank and the coolant tank can be located separately.
Also, this type of cooling allowed to reduce the size of the product and increase the power up to 63-160 MV * A.
With this cooling option, the blowing and circulation systems work constantly, and if one of them is turned off, then the transformer is not allowed to operate.
The NDC system differs from the DC in that the NDC implements a directed oil circulation.
Cooling systems "Ts" and "NTs"
This type of cooling is used for autotransformers and transformers with a capacity of 160 MV * A and more, and the main feature is that in addition to oil, water is used for cooling.
Here water is chased along a special circuit and cools the oil, which is also forcedly circulated through its system. In this case, water replaces the fans.
In such a system, the maximum oil temperature is 70 degrees Celsius. These systems must also be constantly in operation.
The NC system differs from the C in that it implements a system with a directed oil flow. And such a system is used in autotransformers and transformers with a capacity of 630 MV * A.
That's all I wanted to tell you about the types of cooling systems for power transformers and autotransformers. If the article turned out to be useful or interesting to you, then rate it like it and thank you for your attention!