Methods and devices are provided for determining the number of open phases and which particular phases may be open in capacitor bank system. Detecting open phases may include determining a neutral current of the capacitor bank system. According to one detection method, in response to a magnitude of the neutral current being greater than a threshold value, an IED may calculate an aggregate power phasor for the phases of the capacitor bank system with respect to each rotation. According to another detection method, in response to the magnitude of the neutral current being greater than a threshold value, an IED may calculate an individual power phasor for each of the phases of the capacitor bank system with respect to each rotation. Based on the magnitude and angles of the power phases, the IED may determine the presence of open phases and which particular phases may be open, respectively.