Teach You To Determine The Capacity Of A Distribution Transformer

According to the number of transformers in the total step-down substation, the root operation of the transformer has the following two ways:
1. Clear reserve. The open backup mode of the transformer means that there are two transformers, one is working and the other is in backup. When the transformer is repaired or fails, the backup transformer is put into operation and is required to carry the full load. The capacity of each transformer is determined by 100 percent of the calculated load, that is, SrT≥ 100 percent SJS.
2. Dark reserve. The dark backup mode of the transformer means that during normal operation, two transformers work at the same time, each transformer bears half of the load, and the load rate of each transformer is less than 80 percent. When the transformer is repaired or faulty, the other transformer will carry the full load as far as possible, and the transformer will be overloaded at this time.

The current specification GB 50059-2011 3.1.3 [GB 50053-2013 3.3] all require: substations equipped with two or more main transformers, when a main transformer is disconnected, the capacity of the remaining main transformers (including overload capacity) should meet the requirements of all first and second load power. That is to say, in addition to meeting the requirements of each transformer’s own load, it is also necessary to consider that when one transformer is repaired or faulty, it can meet the requirements of all the first and second loads.
The specification requirements are the lower requirements of the design, and the capacity of the transformer will be selected according to the actual needs in the actual design.