Optimal Blocking Devices Placement for Geomagnetic Disturbance Mitigation Based on Sensitivity of Induced Geoelectric Fields

When geomagnetic storms occur, geomagnetically induced currents (GICs), as a kind of quasi-DC, flow through the transformer and cause the increase of reactive power loss (
$Q_{\mathrm {GIC}}$
). Several mitigation actions (e.g., changing grid topology or installing blocking devices) exist that can reduce the harmful GIC effects on the grids. Making such decisions can be challenging, because the magnitude and direction of the induced geoelectric fields (IGFs) are uncertain and non-stationary. In this paper, the sensitivity of voltage and GIC to IGF is first calculated, and the joint voltage/GIC sensitivity feature space is constructed based on principal component analysis. On this basis, scenario clustering is conducted to obtain voltage/GIC sensitivity scenarios. This scenario not only reflects the uncertainty of IGF itself, but also reflects the impact of geomagnetic disturbance (GMD) on the system operation state. Combined with the structural parameters of Jiangsu power grid, the placement of blocking devices (BDs) is optimized. Compared with the constant IGF scenario and the IGF intensity scenario, the expected value of
$Q_{\mathrm {GIC}}$
based on the sensitivity scenario decreases more.