Nowadays, series capacitors are frequently used to increase the transfer capacity and reduce losses on long transmission lines. They also play an important role in improving the voltage stability of the grid. In addition to the positive contributions, it is known that series capacitors affect the operation of distance relays negatively in series-compensated lines and adjacent lines. In this study, a protection algorithm based on wide-area monitoring is proposed using the K-NN classification method to protect series compensated transmission lines in steady-state. The algorithm is tested offline in the radial grid created in the Digsilent Power Factory program. In short circuit scenarios, 2-phase, 3-phase, 2-phase to ground and single-phase to ground faults are analyzed under different fault impedances. According to the results, in case of short circuit faults at certain locations of the lines, the proposed algorithm has determined the faulted line accurately. After the faulted line has been determined, a protection scheme is also proposed for the network.