A Reduction Approach for Load Pickup Amount Considering Thermostatically Controlled Loads

Abstract

The additional power demand caused by cold-load pickup restricts the simultaneous restoration of all the loads of a substation due to excessive loading on the network elements and violation of limits. In the proposed approach, the load pickup amount can meet system requirements based on direct load control of TCLs during cold-load pickup. At first, post-outage load pickup amount is evaluated based on the TCLs aggregated power estimation method considering the outage time. Then, considering transient safety constraints and the available recovery power of power system, an optimization model is established to calculate the maximum restorable load amount. Finally, based on direct load control technique, a reduction approach for load pickup amount is proposed to reduce the load amount during restoration, which guarantees the one-step load pickup amount is lower than the maximum restorable load amount. The simulation results demonstrate that the proposed method can accomplish load pick-up at each step during load restoration reliably.