Effects of geomagnetic storms on long distance AC transmission systems

This chapter discusses the effects of geomagnetic storms on long distance alternating current (AC) transmission systems. Solar Induced Currents (SICs) are the cause of many detrimental effects on power systems. The large blackout of North East USA and Canada of 1989 linked to a large solar activity definitively marks a milestone in the scientific research and activity in this field. The chapter presents an analysis of the effect of numerous blackouts that occurred worldwide on long transmission line. It also describes the beneficial effect that some new equipment such as Static Var Compensators (SVCs) can play in preventing malfunction when an appropriate coordinate compensation strategy is applied. The chapter explains the geomagnetic storms. It discusses how are these formed and highlights that the geomagnetic disturbances produce an induced Earth-Surface Potential (ESP). Therefore, they can cause problems on electric power system and on the communications system. The chapter also investigates a methodology for improving load capability of a long AC transmission lines and explores how the maximum-transferred power on the transmission system is seriously affected by the presence of SICs.