The electrical performance of composite insulators with adhered ice is less than that of porcelain or glass insulator strings, which is mainly caused by the shed configuration differences. In this paper, the shed configuration optimization for ice-covered Extra High Voltage (EHV) composite insulators is discussed in order to improve the electrical performance of ice-covered composite insulators. The effects of the position and length of the air gaps on the electric field distribution of ice-covered composite insulators are investigated and analyzed based on the electric field calculation model. The basic optimization principles of the shed configuration for ice-covered composite insulators are based on the electric field calculation results. Moreover, the artificial icing flashover tests on the ice-covered composite insulators with different shed configurations were carried out in artificial climate chamber, and the flashover path was recorded by a high speed camera. According to the flashover voltage and the flashover path of composite insulators with different shed configurations, it can be concluded that the composite insulators with large shed spacing and various shed diameters have better electrical performance and can be used in the transmission lines across the icing area. (C) Koninklijke Brill NV, Leiden, 2012