SALS – Smart Adaptive Load Shedding

Load shedding (LS) is the last firewall and the most expensive control action against power system blackout. Conventional under frequency LS (UFLS) schemes determine the load drop locations independently of the event magnitude, being the location, frequency thresholds and stage time delays of LS relays pre-specified and constant values. In the decentralised method proposed in this project the aforementioned settings are determined online based on voltage deviation from pre-disturbance value. It means that higher frequency thresholds are assigned to the loads that experience more voltage decay, which are typically located in the vicinity of disturbance location, leading to the need of curtailing less power and thus, to disconnect fewer users during the emergency shutdown. At the same time the proposed method is able to bring the voltage and frequency to the desired interval faster than the UFLS.
The proposed method simultaneously benefits from individual UFLS and under voltage LS (UVLS) features which operate in the power system without coordination.