An UHV Grid Security and Stability Defense System: Considering the Risk of Power System Communication

An ultra high voltage (UHV) ac and dc interconnection will become the foundation of China's future smart grid. Due to the wide spread of interconnected regions, the distance between control stations will increase dramatically. Therefore, the communication system's reliability and real-time performance will become increasingly crucial. However, failures of the communication system, such as interruptions, latency, and bit error, are inevitable. This paper uses the UHV grid security and stability defense system (SSDS) as an example to analyze its requirements for communication and the impact of communication failure on the system's performance. The effect of communication latency on the power system's stability is analyzed quantitatively and qualitatively. Based on this analysis, a framework of an UHV grid SSDS considering the risk of the communication system is proposed. A preliminary power system and communication system co-simulation tool is developed to perform a case study. The case study demonstrates that communication latency in the UHV grid changes the control strategy's effectiveness due to a delay in executing the control strategy. Furthermore, communication latency will negatively affect the power grid's stability.