An Integrated Protection Scheme Based on a Distance Approach

Abstract

This paper presents a new integrated protection scheme based on distance protection technique. An integrated protection relay is installed at a substation and interfaced to every line through the CTs and busbar VT. The relay is also interfaced to the substation communication network which is communicated with all neighboring substations. The directional detection, phase selection and adaptive distance algorithms are implemented into the relay with multiple distance settings for the protection of every line sections connected to the substation busbar. When a fault occurs on any of the line associated with the substation, the relay will firstly determine the faulted direction, then the faulted phase. The distance algorithm together with the relevant setting will then apply to the faulted line/phase to determine the fault location. The relay will trip instantly when a zone 1 fault is detected. The relay will communicate with relevant relay at remote ends to determine whether to trip or restrain when a zone 2 fault is detected. The paper includes studies of a typical multi section system, which shows that the new scheme not only offer the new protection features for individual power line, but also provide the characteristics of integrated protection