During system restoration, what effect does the closure of capacitor banks have?

The closure of capacitor banks during system restoration plays a critical role in voltage management. When capacitor banks are closed prematurely—before the system has been adequately restored—it can lead to high voltage issues. This occurs because capacitor banks contribute reactive power to the system, which can elevate voltage levels if the demand for that reactive power is not properly balanced.

If the system is still vulnerable or destabilized, the addition of reactive power from the capacitors can push voltages to levels that may exceed acceptable limits, potentially causing equipment damage or operational issues. Therefore, careful timing and coordination are essential when reintroducing capacitor banks during the restoration process to avoid such complications.

The other choices do not accurately reflect the specific impact of closing capacitor banks at the wrong time during system restoration. For instance, while stabilizing voltage across a transmission line is a benefit of correct capacitor operation, it is not the primary risk associated with premature closure. Similarly, though closing capacitor banks can affect system load and efficiency, the immediate concern in the context of restoration is the potential for high voltage problems.