Effects of Series Compensation Capacitors on Geomagnetically Induced Currents

Abstract

A series compensation capacitor bank presents a high-impedance path to geomagnetically induced currents (GICs), which are induced into the power network during geomagnetic disturbances. The notion that a series capacitor generally blocks GIC is only true for the transmission circuit connected in series with the capacitor. In many cases, the series capacitor simply re-distributes GIC in the network and may actually increase GIC flow at terminal stations. The conditions under which an increase in GIC can take place and illustrative examples with and without piecewise layered earth modeling are discussed.Index Terms-Electric field, geomagnetically induced currents (GICs), geomagnetism, reactive power control.

Resilience in an Evolving Electrical Grid

“…Existing placement-optimization algorithms [106][107][108] exploit the property that only a small number of transformers are susceptible to GICs; this depends on transformer core type, location within the transmission network, and the geometry of the network. Studies for the placement of these devices observe some key characteristics with their effect.…”

Optimal placement of grounding small resistance in neutral point for restraining voltage fluctuation in power grid caused by geomagnetic storm

“…Another approach is to defence against geomagnetic storms through the power system dispatch centre, which includes modifying the parameters of electric equipment such as static var compensator and relay protection devices, combined with the geomagnetic storm forecast information. For example, cut off the transmission lines with a heavier GIC magnitude, which means segregate the flowing path of GIC from the high-or low-voltage side of transformers to prevent the GIC from resulting in DC bias saturation of other transformers [6][7][8].…”

“…Taking the minimum configuration cost of GIC isolation device installed in transformer neutral as the goal, their solution can defence the impact of severe geomagnetic storm on the power system to some extent [7]. Subsequently, literature [8] also proposes a global optimisation mitigation scheme for large-scale power grid. Aimed at minimising the reactive power losses derived from GIC, an optimal configuration method based on mixed-integer second-order cones programming algorithm is put forward to reduce the reactive power losses caused by GIC event in transformers.…”

Fuzzy logic controlled variable resistor for suppressing GIC in transformers

“…GICs are quasi-DC currents that can disrupt the normal operation of the power system and can, in some cases, damage equipment [1,2]. On [13][14] March of 1989, the hydro Québec power system collapsed. A geomagnetic storm hit the earth with a magnitude of 500 nT/min.…”

“…During the GIC presence, due to harmonics, some compensators will trip and the line voltage drops, thus, other compensators will trip as well as a result of overloading while trying to compensate the reactive power losses and voltage drops. This might destroy the fixed capacitors from overcharging as well, which leads to an even more severe voltage sag [8,13,14].…”