The integrated protection for power network

This paper presents a novel protection and automation scheme for distribution networks called transient polarity directional comparison scheme. The technique is based on the detection and processing of fault generated transient current signals, in which specially designed protection relays are installed at each substation of a distribution network. The transient detection unit of the relay detects the fault generated super-imposed current signals. The transient polarity identification algorithm is then applied to the super-imposed signals to identify the polarity of the signal detected. The direction of a fault is determined by comparison of the polarity of the signals derived from all the line sections connected to the substation. The actual faulted section is identified by processing the directional information from various substations, with which the integrated protection of power network is realized.