Kalman filter based incipient fault detection method for underground cables

An incipient and self-clearing arcing fault can be utilised as a precursor of an imminent permanent failure for monitoring of underground cables. Due to very short duration of the incipient faults, generally they cannot be detected by conventional protection relays. This study presents a new method for detection of incipient cable failures by using measured current and voltage at one end of the cable. The incipient faults are detected using an innovation signal calculated from the measured fault current via a Kalman filter. Upon change detection by the innovation signal, the change is checked for discriminating possible incipient fault from other similar conditions. The proposed method is evaluated using several simulations and field data collected from a real network. The results confirm that the method can achieve high accuracy and speed for detection of cables incipient faults.