Design Criteria for Line Differential Current Protection Scheme

Abstract

Line current differential protection creates challenges for relay design and application. From a design perspective, the distributed nature of the line current differential system imposes limits on the differential current to enable the differential protection principle. From the application perspective, line current differential schemes are concerned with leakage current, charging current, intermediate faults, CT saturation. This paper reviews technical solutions to the line current differential design and application, addressing the common design constraints and distance driven application needs.