Yip H.T., Moscoso M., Lloyd G., Liu K., Wang Z. ALSTOM Grid, 21 с.Traditional bias characteristic:
Improves stability during CT saturation.
Considers 2nd harmonic blocking or restraining to provide stability during inrush.Traditional bias characteristic limitations:
Dual slope characteristic on its own may not maintain stability without requiring excessive over-dimensioning of the CTs.
2nd harmonic technique may slow down the bias differential element when CT saturation occurs during internal faults.
