Oil Immersed Transformer Selection Points

Load property
​1) When there is a large number of a * or secondary load, it is appropriate to install two or more transformers, when any transformer is disconnected, the capacity of the remaining transformers can meet the power consumption of a * and secondary loads. The first and second loads should be concentrated as much as possible and should not be too scattered.
​2) When the seasonal load capacity is large, special transformers should be installed. Such as large civil buildings in the air conditioning freezer load, heating load and so on.
​3) When the concentrated load is large, special transformers should be installed. Such as large heating equipment, large X-ray machine, arc furnace and so on.
​4) When the lighting load is large or the power and lighting use of shared transformers seriously affect the quality of lighting and lamp life, a special lighting transformer can be set up. In general, power and lighting share a transformer.
​Use environment
​Under normal medium conditions, oil-immersed transformers or dry transformers can be selected, such as industrial and mining enterprises, agricultural or attached substations, residential substations, etc. Available transformers are S8, S9, S10, SC (B) 9, SC (B) 10, etc.
​Temperature environment
​① Maintain long-term stability at 220℃
​② It can withstand short-term operation at 350℃
​③ In a wide range of temperature and humidity, maintain stable performance
​④ At 250℃ temperature, will not melt, flow and combustion
​⑤ At 750 ° C, it will not release toxic or corrosive gases
​Electric load
​1) The capacity of the distribution transformer should be integrated with the facility capacity of various electrical equipment to calculate the load (generally excluding the fire load), and the apparent capacity after compensation is the basis for selecting the capacity and number of transformers. General transformer load rate of about 85 percent. This method is simple and can be used to estimate the capacity.
​2) In GB/T17468-1998 “Power Transformer Selection Guidelines”, it is recommended that the capacity selection of distribution transformers should be determined according to GB/T15164-94 “Oil-immersed power transformer load Guidelines” or GB/T17211-1998 “Dry power transformer load Guidelines” and calculate the load to determine its capacity. The above two guidelines provide a computer program and a normal cycle load diagram to determine the distribution transformer capacity.