Self-Security for Grid-Interactive Smart Inverters Using Steady-State Reference Model

Smart inverters can exchange information with other devices through a shared communication link, making the inverters more prone to receive harmful commands from external parties. This erroneous data can be received due to an anomaly in the system, such as a malfunction in the communication link, unintentional utility operator action, or a cyber-attack. In this paper, a device-level self-security strategy is implemented using reference models for a grid-interactive inverter to examine the incoming power setpoints, detect the anomalies, and protect the system accordingly. The PQ setpoints received from the utility supervisory controller are autonomously examined using the inverter’s normal and stable operating regions before engaging the setpoints to the inverter’s local controller. Grid parameters are estimated in real-time during the examination process. The efficacy of the self-security algorithm is tested using a hardware setup, which includes a three-phase 5kVA SiC-MOSFET inverter and a 12kW, 30A regenerative grid emulator. The results verify that the proposed method can prevent harmful PQ setpoints to get engaged to the local controller.