Residual current compensation (RCC) for resonant grounded transmission systems using high performance voltage source inverter

A novel FACTS equipment, the residual current compensation (RCC), overcomes the restrictions of resonant grounding completely and make the method of Petersen perfect: a voltage source inverter (VSI) in the neutral system generates the voltage required to actively compensated the residual current whilst continuing the power supply. A residual current compensation was installed in an 110 kV grid, involving 18500 km of lines. The RCC consists of a 5.5 MVA-multi-level-VSI using GTOs. The paper describes the design criteria with respect to the relevant grid parameters and the closed loop control based upon the admittance of the neutral system. The effectiveness is proven by carried out field tests. The perfect earth fault management for both extended overhead lines and cables may create reviewed guidelines of planning resonant grounded 110 kV grids with higher availability and power quality.