When SWEPCO must reduce the load on its electric system in an emergency, we use "controlled outages. The Southwest Power Pool (SPP) tells SWEPCO and other electric utilities how much electric load we must reduce.
In our emergency plan, SWEPCO matches the number of circuits that add up to the amount of electricity we are required to reduce. For example, a circuit might have 500 to 1,500 customers, and SWEPCO might need to disconnect 25 circuits. Those circuits would be in different locations around SWEPCO’s three-state service territory. SWEPCO would temporarily disconnect power to these circuits, and when possible, rotate to another group of circuits to limit the impact in any one location to one to two hours. It may take longer to get the power back on because of electric system issues or weather conditions. We make every effort to avoid interruption of service to critical public health and public safety facilities.
When SWEPCO gets word from SPP that the controlled outages have reduced power to bring balance back to the overall energy delivery system, then the controlled outages can end. During a longer emergency period, SPP could order additional controlled outages until the system returns to lower levels of emergency and then to normal operations.