Strategies to secure the IEEE 1588 protocol in digital substation automation

The IEEE 1588 Precision Time Protocol seems to be a promising way to handle the synchronization requirements of tomorrow´s substation automation based on IEC 61850. While a specific working group is tackling the security aspects of the protocols defined by IEC 61850, a secure IEEE 1588 protocol remains mostly uncovered in the specific context of substation automation. In this paper, we are focusing on securing IEEE 1588 for substation automation. We are analyzing and classifying the different attacks relevant for a substation and proposing a way to handle the logical disconnection of the time server and its clients that appears whenever an attack occurs. The method based on clock drift correction allows to keep a node synchronized for different period of time depending on the correction mechanism used. The implementation and experiments of the different drift correction mechanisms shows the tradeoff between the accuracy of the correction and the required computational time. By analyzing the different experiments, we can then match the computational power of a class of devices present in a substation and a correction technique.