Inclusion of Pre-Existing Undervoltage Load Shedding Schemes in AC-QSS Cascading Failure Models

A challenging problem facing AC-Quasi-Steady-State (AC-QSS) cascading failure models of power system is the divergence issue primarily stemming from voltage collapse phenomena. In reality, there are undervoltage load shedding (UVLS) relays, which aim to prevent such a by pre-specified fraction at buses where corresponding voltages fall below threshold. However, capturing UVLS action in QSS very difficult, because most time model cannot generate an equilibrium threshold due divergence. To address this problem, current have applied different variants uniform (ULS) till convergence achieved, differ ground truth. order solve this, we propose methodology that leverages post-ULS flow as starting point when occurs. condition, sensitivity index coupled with magnitudes used recognize prone collapse. The scheme then these buses. verify accuracy results, also present suitable dynamic cascade appropriate limits and protection details can selectively capture action, thereby revealing proximate Predictions proposed validated against those for representative cases IEEE 118-bus system. addition, results contrasted two ULS schemes on 2383-bus Polish