Integrated protection of power systems

This paper reports on the development of integrated protection for power system. The concept of integrated protection is introduced, in which a centralized protection system (or relay) provides the protection of multiple power plant or a substation. Examples are given of the protection schemes with the features of integrated protection which are currently under development. A novel integrated protection scheme for substation and network protection is described. 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 network. The transient detection unit of the relay detects the fault generated transient current signals. The transient polarity identification algorithm is then applied to the transient 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