In recent years, a new type of pre-loaded box-type substation, buried box-type substation are springing up in some places, in the residential area, park plaza, city street light engineering, etc, it can be seen from time to time, to change, as the name implies, transformer installed under the ground, the ground part is high and low voltage power distribution equipment, up and down through the vertical arrangement, and its installation area greatly reduced, and through the shape optimization design, the part to make landscape decoration or light box advertising, indeed to beautify the ornament and decoration role in the surrounding environment, unlike other box-type substation, installed very not coordinated with the environment.

It is because buried type box changes to have above a lot of advantages, it got the favour of a lot of owners.

However, through the operation and daily maintenance inspection, the author has a deeper understanding of the buried transformer. In my opinion, the buried transformer should not be promoted and used as a public transformer in residential areas.

For one thing:

Property with 70 residents of the residential area, the design life of electrical products including the ground changed in 20 years or so commonly, after years of affirmation to transform update, here will involve the issue of construction time, generally change or indoor distribution box, power outage update time can be completed in one day, the ground is adopted directly buried installation, if to change the overall replacement, will have great trouble, transformer box directly buried underground, what will happen when lifting earth subsidence, must after the excavation, to install a new box, this will greatly increase the quantity and the outage time,

In addition, the original plan of buried transformer was adopted, and it was almost impossible to replace other plans during the reconstruction due to land occupation and other reasons.

The other is difficult maintenance, once the transformer needs maintenance, because the transformer box space is small, conditions are quite limited, field maintenance is difficult, if you want to replace the transformer, you must first lift the upper end of the high and low distribution part, remove the cable, the workload is huge, the blackout time may not be expected.

Thirdly, because the body structure and installation method of underground transformer in the water easily, in the village, ground drain almost flat with the ground, in case of precipitation rainfall is large, the port will become a water inlet flow backward, then automatically submersible pump are powerless, but risk is far greater than the water is installed on the transformer transformer room in the basement.

Although the transformer protection grade up to IP68, but the risk of flooding operation can be imagined, after a long service life, waterproof sealing rubber aging, once the water, the consequences are serious.

During a tour before the typhoon, the writer found that each box of underground transformer in more or less have the phenomenon of water, although not achieve automatic drainage water, but as a result of transformer thermal effect, the casing includes the ground distribution box humidity is bigger, even if has a temperature and humidity automatic control exhaust, but the box is in damp environment for a long time, will reduce the service life of the product.

Fourthly, due to the compact size of the buried transformer box, all electrical operations are outdoors. In case of bad weather, it will bring great inconvenience and insecurity to operators.

Based on the above reasons, the author thinks that residential area buried variable is a power distribution terminal, can hardly be switch circuit, and a single capacity is larger, the power supply area is bigger also, such as a power outage for a long time, will cause serious impact to residents, the understanding of some large complete sets of enterprises, to more than 500 kva buried products, they are not recommended, although the real estate company based on its own sake, for it, but as a community public transformer should choose carefully.

Of course, as a new product, buried box transformer still has its advantages. It is suitable for application and promotion in some occasions with small capacity and high landscape requirements, such as park green space and urban road lighting.

(zhu guobo)