How many MWs are flowing into the low side of a transformer with a 0.8 power factor and 150 MW flowing out on its high side?

To determine how many megawatts (MW) are flowing into the low side of a transformer when you know the output on the high side and the power factor, it’s important to understand the relationship between real power, apparent power, and power factor.

In this case, the transformer’s high side output is stated as 150 MW. The power factor of 0.8 indicates the efficiency with which the electrical power is being converted into useful work. Real power (measured in MW) represents the actual power used for work, while apparent power (measured in MVA) is the product of current and voltage in the system.

When considering power flow through a transformer, we have to account for losses and the efficiency of the transformer, which means the power flowing into the low side is usually greater than on the high side by a factor dependent on the transformer’s power factor.

Focusing on the correct answer: If the high side outputs 150 MW of real power and considering the specified power factor of 0.8, we can calculate the apparent power required to deliver this real power.

Using the formula:

Real Power (MW) = Apparent Power (MVA) × Power Factor

Rearranging gives:

Apparent Power