2. The Classification of FCL

In the attempts to develop an FCL that satisfies the requirements of the power system, a large number of FCL technologies have been proposed by researchers and companies. Proposing novel topologies or improving the previous structures based on depth computer analysis, laboratory experimental tests, and live-grid deployment are the consequence of these activities. Several categories have been proposed in papers, standard, and technical reports to classify FCL structures [1, 2, 8, 11, 12]. IEEE standard divides FCLs into two sets consisting of Type A and Type B. The FCL capability to the current interruption is the distinct property between Type A and Type B. The former is only capable to limit fault current, whereas the latter is able to interrupt fault current as well as current limiting. In other words, Type B plays the role of FCL and CB. In a more detailed classification, they individually have two subsets namely Type A1, Type A2, Type B1, and Type B2. The insertion impedance by Type A1 and Type B1 into the system is linear during fault conditions, whereas the nonlinear impedance is provided by Type A2 and Type B2 FCLs. This issue can be graphically illustrated with the help of Fig. 2.1. It should be noted that the experimental waveforms have more distortion.