Voltage sag source location technology based on corresponding sequence components

Determining the relative region where voltage sags originates is useful to identify the responsible party causing the power quality problem and monitor system or equipment operating condition. As different kinds of voltage sag will cause different sequence components to change according to the neutral point operation mode in the distribution system, a modified incremental impedance-based method for determining voltage sag source (VSS) location is proposed in this study. This study starts with the VSS direction theory based on incremental impedance, and derives location criteria for different types of VSSs according to the neutral point operation mode of the Chinese distribution network. The VSS location strategy is finally accomplished through the analyses of voltage sag´s capacity for passing through the service transformer and the impact of system transient on incremental impedance calculation. The method locates various VSSs based on existing PQ measure points and has clear physics concept. Theoretical analysis, simulation and lab experiments have verified its effectiveness.