1. Select the transformer according to the load condition:

1. When there are a large number of primary or secondary loads, two or more transformers should be installed. When any one of the transformers is disconnected, the capacity of the remaining transformers can meet the power consumption of the primary and secondary loads. The primary and secondary loads should be concentrated as much as possible and should not be too dispersed.

2. When the seasonal load capacity is large, a special transformer should be installed. Such as the load of air-conditioning refrigerators and electric heat loads for heating in large-scale civil buildings.

3. When the concentrated load is large, a special transformer should be installed. Such as large heating equipment, large X-ray machines, electric arc furnaces, etc.

4. When the lighting load is large or the power and lighting use a shared transformer, which seriously affects the lighting quality and the life of the bulb, a special lighting transformer can be installed.

2. Select the transformer according to the use environment:

1. Under normal medium conditions, oil-immersed transformers or dry-type transformers can be selected according to the situation, such as independent or attached substations in industrial and mining enterprises, agriculture, independent substations in residential areas, etc. Available transformers are S8, S9, S10, SC(B)9, SC(B)10, etc.

2. In multi-storey or high-rise main buildings, non-combustible or flame-resistant transformers should be selected, such as SC (B) 9, SC (B) 10, SCZ (B) 9, SCZ (B) 10, etc.

3. In places where dusty or corrosive gases seriously affect the safe operation of transformers, closed or sealed transformers should be selected, such as BS 9, S9 – , S10- , SH12-M, etc.

4. High and low power distribution devices without flammable oil and non-oil-immersed distribution transformers can be installed in the same room. At this time, the transformer should be equipped with an IP2X protective shell for safety.