Series compensation, power swings, and inverter-based sources and their impact on line current differential protection

Abstract

It is common knowledge that the line current differential protection principle is not susceptible to unusual system conditions. This is true and straightforward regarding protection security but is not immediately obvious when considering dependability of protection. As a result of dismissing the impact of unusual system conditions, the effect of series compensation, power swings, and inverter-based short-circuit current sources on line current differential protection is not well understood. This paper briefly touches on protection security but focuses on the dependability of line current differential protection under a number of specific system conditions, including series compensation, power swings and off-nominal frequency, and inverter-based sources. This paper reviews the impact of each of the mentioned conditions and provides illustrations using simulations.