Impact of Fault Current Limiters on Existing Protection Schemes Luciano Martini*, Karl-Heinz Hartung on behalf of CIGRE Working Group A3.16 (**) (**) Members: H. Schmitt, Convener (Germany), J. Amon (Brasil), D. Braun (Switzerland), G. C. Damstra (The Netherlands), K.-H. Hartung (Germany), N. Higuchi (Japan), J. Jäger ( Germany), J. Kida (Japan), , M. Steurer (US), X. Waymel (France) CIGRÈ INTERNATIONAL TECHNICAL COLLOQUIUM, 12-13 September 2007, Rio de Janeiro, Brazil. * CESI RICERCA The paper presents an overview on the activities of the CIGRE Working Group (WG A3.16) which focuses on the interaction between fault current limiting (FCL) technologies, both existing and novel, and different protection systems in medium voltage (MV) and high voltage (HV) systems. Based on the different FCL behaviors a set of criteria are derived to qualify the potential impact of each type of FCL on the various protection principles. The concept of protection zones is used to analyze the influence of FCLs on the protection schemes at different potential applications. Basis for this investigation is the Technical Brochure No. 239 [1] of CIGRE Working Group (WG A3.10).