Implementation and Testing a Robust Data-Repairing Method for Protection IEDs on Process Bus

Abstract

Modern power systems heavily rely on fast and reliable protection and control systems. However, Sample Value (SV) packets transmitted via Process Bus protocols are susceptible to delays and losses during transmission, particularly during congestion of communication networks. The vulnerability of Intelligent Electronic Devices (IEDs) to network delays and consecutive packet losses raises concerns regarding the processing of SV packets under abnormal communication conditions. This paper investigates the impact of consecutive SV packet delays and losses on transformer differential protection and IED performance. Furthermore, it proposes a novel approach called Data-Repairing for Protection IED (DRPIED), which has been implemented and tested using a Hardware-in-the-Loop setup under various load and transient conditions. The results highlight that IEDs are limited in their ability to estimate more than one missing SV packet. While one vendor's protection IED blocks beyond one missing packet for approximately 0.5 seconds, estimation errors from other vendors can result in false tripping. However, the developed DRPIED method demonstrates the capability to securely estimate up to 9 missing SV packets during load and transient fault scenarios, even with varying decaying direct current (DC) levels. Overall, this study sheds light on the challenges posed by consecutive SV delays and losses in a multi-vendor environment and presents a solution to mitigate the impact on differential protection systems.