If Station A is at 345 kV and Station B at 343 kV, which capacitor should be put into service when the system load is expected to increase?

When considering the operation of capacitors in a power system, the key principle is to help regulate voltage levels and provide reactive power support. In this scenario, we have Station A at 345 kV and Station B at 343 kV. The difference in voltage levels indicates that Station A is at a higher voltage than Station B.

When the system load is expected to increase, reactive power needs also typically rise, which can cause voltage levels to drop. The capacitor bank that is connected to the lower voltage level, in this case, Station B at 343 kV, is more beneficial to put into service. This is because using the capacitor at the lower voltage location can effectively raise the voltage in that area, providing the reactive support necessary to stabilize the system and prevent issues related to undervoltage conditions.

Implementing the capacitor at Station A would not be as effective in managing the load increase, given that it's already at a higher voltage level. Thus, the best option is to connect the capacitor associated with Station B to properly address the voltage drop from the anticipated load increase.