The reactive power consumed by the transformer is generally about 10% to 15% of its rated capacity, and its no-load reactive power is about 1/3 of the full load. Therefore, in order to improve power factor (PF) of the power system, the transformer should not operate at no-load or in a long-term low-load operation state. Vigorously improving the power factor of transformers, reducing line losses, and saving energy are the inevitable directions for the development and progress of the current power grid.
How to calculate the reactive power of a transformer?
Assume that the rated capacity of a transformer is S=600kVA and the power factor is 0.8.
Then the active power is P=S*power factor=600*0.8=480kW
Reactive power is Q=(S^2-P^2)^0.5=360kVAr
How to calculate the compensation capacity(kVAr) with Load, PF?
A three-phase motor has 480kW real power load at operating at 0.8 PF, we need to improve the power factor to 0.95.
Let us calculate the required reactive power in kVAR (capacitor bank or Static Var Generator) to be connected across the motor?
Here, PF1 = 0.8, PF2 = 0.98
Required Q(kVAr) = 480 x tan (cos-1(0.8)- cos-1(0.98)) = 263kVAR.
Recommend compensation capacity: 263kVAr/0.8=328kVAr
Hence we can connect 325kVAR Static Var Generator panel for improving the power factor from 0.8 to 0.98. If required target Power Factor is >0.95, we advice Static Var Generator or our hybrid power factor correction to compensate.
How to compensate reactive power totally when energy meter at MV side?
We have another special SVG products,which support SVG at Low voltage side but CT can connect to Medium voltage side. And at this condition, Static Var Generator can compensate the reactive power of transformer itself.
Contact us [email protected] for details.
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