Allocation of Voltage Sag Monitoring Based on Improved S-Transform and Exposed Area

The paper uses begin-end moment and duration of voltage sag to modify the vulnerable area, and uses particle swarm optimization (PSO) algorithm to optimize the monitoring allocation to provide reliable data for the fault source location of voltage sag. The improved S-transform is applied to estimate the begin-end moment and analyze the sag type, and which also provides compensation for the accuracy of the vulnerable area analysis. The PSO algorithm sets the minimum amount of monitoring as the objective function and the observables of all network sensitive loads as constraint conditions, then the paper simulates the PSO algorithm by MATLAB in the IEEE 39 nodes system to select the most suitable solution of monitoring optimization allocation.