What is the equation for calculating MVAR output of a shunt capacitor?

The formula for calculating the MVAR output of a shunt capacitor is grounded in the relationship between voltage and the reactive power it produces. In this case, the correct approach utilizes the rated values of voltage and reactive power.

The equation MVAR output = MVAR rated (V actual/V rated)^2 reflects that the output of the shunt capacitor is dependent on the square of the ratio of actual voltage to the rated voltage. This is because the reactive power produced by the capacitor is directly related to the voltage across it. When the actual voltage differs from the rated voltage, the output changes proportionally to the square of that change. When the actual voltage is less than the rated voltage, the output in MVAR will decrease, reflecting the reduced capability to provide reactive power. Likewise, if the actual voltage approaches the rated voltage, the capacitor will output its rated MVAR.

The other options fail to capture this fundamental behavior of shunt capacitors with respect to voltage and reactive power. Some options suggest a linear relationship or misinterpret the interaction between voltage and output, which does not accurately represent how shunt capacitor banks function within an electrical system. This understanding is essential for effective transmission operations and managing reactive power in power systems.