Sensitivity analysis of transient short circuit current response to the penetration level of non-synchronous generation

Abstract

The increasing penetration of inverter connected non-synchronous generation (NSG) in future power systems may result in a large displacement of synchronous generators. Hence, the dynamic characteristics of the power systems may change in ways that have not been experienced yet. In particular, short circuit (SC) current response in future power systems might be significantly affected due to the increased penetration of such generation. In turn, this can significantly affect both the operation of protective relays and the relay settings. This is due to different characteristics of SC currents injected to the grid from NSG, compared to the conventional synchronous generation. This paper focuses on investigating of transient SC current response in future power systems with high penetration of NSG. Hence, to address this, in this paper we investigate the impact of a wide range of factors that influence the SC current contribution from NSG based on fully-rated converter technology. Our analysis also considers the impact of different fault ride through (FRT) controls, designed according to different grid codes, on the SC current response of NSG. Then, the sensitivity of the transient SC current to the increased penetration of NSG is monitored and analyzed. Firstly, simulation studies are conducted using a single-machine infinite bus test system where the SC response of a NSG is comprehensively studied. Secondly, our findings are also tested and verified using IEEE 9-bus test system at different penetration scenarios of NSG using DIgSILENT PowerFactory.