Solar Cycle 25 has been characterized by enhanced and prolonged geomagnetic activity, raising concerns about the vulnerability of electrical power systems to space weather effects. This study investigates the relationship between solar activity and geomagnetic disturbances, and examines how these processes drive geomagnetically induced currents (GICs) and associated reactive power fluctuations within the Zimbabwean power grid. Sunspot numbers and planetary Kp index data were obtained from space weather data centers, and processed using MATLAB for temporal alignment and statistical analysis. In addition, Hall-effect clamp-type current probes were installed at the Dema and Warren 330 kV substations to directly measure quasi-DC GICs during geomagnetically disturbed and quiet conditions. Reactive power data for the Dema–Warren transmission line were obtained from ZETDC archives to assess grid response during adverse space weather events. The results show a substantial increase in geomagnetically active periods, with a marked rise in the frequency of (3-hour) intervals characterized by Kp ≥ 4.67 from 2019 through early 2026. This trend coincides with the solar maximum phase of Solar Cycle 25. During severe geomagnetic storms in 2024, GICs reached 3.05 A at Warren and 2.05 A at Dema, with an inter-station correlation of ∼81%, while quiet days showed currents below 1 A. Reactive power deviations of 30–50 MVAr during storm periods further indicate a strong link between geomagnetic activity and voltage instability. These findings demonstrate the tangible impact of Solar Cycle 25 on power system performance in Zimbabwe and underscore the importance of integrating space weather monitoring and mitigation strategies into grid operation and planning to enhance resilience against future geomagnetic disturbances. This research contributes to our understanding of solar-terrestrial interactions and their implications for power grid stability in the face of adverse space weather.
Muchini et al. (Mon,) studied this question.