If the voltage at substation A is 235kV and at substation B is 230kV, how does the reactive power (MVARs) flow?

The correct answer indicates that reactive power flows from substation A to substation B. This is consistent with the principles of how reactive power behaves in alternating current (AC) systems. Reactive power is influenced by the voltage levels at different points in the grid. In this scenario, substation A has a higher voltage (235 kV) compared to substation B (230 kV).

In AC systems, when there is a difference in voltage levels, the reactive power flows from the area of higher voltage to the area of lower voltage. This occurs because the higher voltage can supply reactive power, helping to balance or support the system and alleviate the voltage drop at the lower voltage point.

Therefore, from substation A to B, reactive power flows in the direction of the voltage gradient, which is from the higher voltage (A) to the lower voltage (B), making the correct response clear based on the behavior of reactive power in an electric power system.