Research On Effect Of Geomagnetic Induced Current On Multi-Infeed HVDC Systems

Geomagnetic storms caused by solar activity produce geomagnetic induced currents (GIC). Geomagnetic induced currents (GIC) flow from the grounded neutral to the transformer, magnetizing current of the transformer produces a large number of harmonics. The pollution of harmonic noise will increase largely, consuming a large amount of reactive power, and even transformer will be damaged. The converter transformer that High-voltage DC (HVDC) transmission system adopted in is three-phase transformer group, its response to the DC magnetic bias is very sensitive. And because of the situation of China’s resources and economic development, our country’s HVDC is toward the multi-infeed DC (MIDC) transmission system trends. In recent years, we are at solar maximum years, so the study of the impacts result from geomagnetic induced currents on the Earth, especially on our multi-infeed DC (MIDC) transmission system should not be ignored.This paper describes the generation mechanism of the geomagnetic induced currents (GIC) and its impact on the multi-infeed DC (MIDC) transmission system, and theoretically makes simulation analysis. Simulation model changed from BPA’s3-machine9-bus system model to to get the three-infeed DC transmission system model, the transformers of the model coming from the PSCAD modules use three-phase transformer group consisted of the UMEC single-phase two-winding transformers. The appropriate model based on the changed transformer is used to simulate the invasion of the geomagnetic induced currents(GIC), by the two operating conditions both rated load and light load of three infeed HVDC system observing and recording the changes of the electrical parameters of the system caused of the geomagnetic induced current (GIC), and drawing conclusions. Simulation analysis will demonstrate whether the impact of protection system will occur or not because of GIC. Finally, this paper will make three kinds of effective measures, focusing on the inhibition of geomagnetic induced currents (GIC).