Transformer capacity

Installed capacity and calculated load are two different concepts; for an installed capacity of 6,000 kilowatts, the calculated load might be around 3,000 to 4,000 kilowatts. The KVA rating of the transformer is determined through complex calculations carried out by electrical engineers.

Installed capacity is not equal to the actual load; a significant amount of power is reserved as backup and is not used simultaneously. For economic reasons, it is necessary to select transformers based on the actual load.

Could the moderator provide an outline? How is it calculated roughly? Thank you!

First, it is necessary to tally the various types of loads in the workshop, as shown in the table below (this is merely for statistical purposes and has nothing to do with the selection of transformer capacity). Ammonia stripping reflux pump: 5.5, 2, 1, 1, 11; 5.5, 5.5, 0.8, 0.8, 4.4, 3.3, 5.5. Electric valve (for hydrogen production): 7.5, 3, 3, 0, 22.5; 0, 22.5, 0.8, 0.8, 0, 0, 0. Boiler dosing pump I: 0.55, 2, 2, 0, 1.1; 1.1, 0, 0.8, 0.8, 0.88, 0.66, 1.1. Electric valve (for methanol production): 7.5, 2, 2, 0, 15; 0, 15, 0.8, 0.8, 0, 0, 0. Deoxygenation dosing pump: 0.55, 2, 1, 1, 1.1; 0.55, 0.55, 0.8, 0.8, 0.44, 0.33, 0.55. Boiler liquid storage tank agitator: 0.75, 1, 1, 0, 0.75; 0.75, 0, 0.8, 0.8, 0.6, 0.45, 0.75. CS2 metering pump: 0.75, 1, 1, 0, 0.8; 0.8, 0, 0.8, 0.8, 0.6, 0.45, 0.75. Boiler dosing pump II: 0.55, 2, 2, 0, 1.1; 1.1, 0, 0.8, 0.8, 0.88, 0.66, 1.1.

Second, calculate and select the transformers. Number of units per device, installed capacity (kW), required capacity, total capacity. Equipment name, capacity, power consumption, notes. Pp, Qp, Sp (kW); installed capacity, power consumption, capacity (kW), (kW), (kVAR), (kVA). 54, 39, 15, 2013, 1215, 798, 875.6, 622.69, 1076.73. 45, 22, 23, 805.5, 351, 344.6, 368.76, 276.57, 460.95. Total low-voltage load: 99, 61, 38, 2818, 1565.5, 1142.6, 1244.36, 899.26, 1537.68. Natural power factor: COSφ = 0.809. Reactive power compensation capacity: 500 (maximum capacity, adjustable). Load after compensation: 1244.36, 399.26, 1306.7. Power factor after compensation: COSφ = 0.95. Selected transformers: 2 units of 1250 kVA each. Transformer load rate: 53.40%. Low-voltage load current (A): Ij = 1985. Transformer losses: 11.8, 59.1. Load calculated on the 10 kV side of the transformer: 1256.16, 458.36, 1336.8. Power factor on the 10 kV side of the transformer: COSφ = 0.94. It’s a very complex matter that can’t be explained in just a few words; even ordinary electrical engineers may not be able to handle it

Hahaha, it seems you don’t trust your electrical system at all! Installed capacity and calculated load are two different things; if the installed capacity is 6000 KW, the actual usage might be 3000 KW.

Installed capacity is not equal to the transformer capacity, because you need to take into account the power factor, reactive power, equipment demand factor, and simultaneous operation factor of the equipment

It also depends on the simultaneous operating load of the equipment.

If you look at the calculations using the demand factor method in the fourth edition of the \"Manual for Design of Industrial and Civil Power Supply and Distribution\", you will understand.