Grid-tied smart inverter safety functionality: Fast power quality event detection

This paper addresses the fast detection of electric signal disturbance for advanced smart inverter functionality within the framework of large scale grid integration of renewable energy sources. A statistical-based technique under the fault detection and isolation (FDI) paradigm is proposed for fast detection in power systems. The aim is to improve the performance of interconnection systems and the electricity grid's energy efficiency. The new method developed is based on the CUmulative SUM (CUSUM) algorithm and is applied to a wide set of power quality events to analyse its performance. The results show that the method generates residuals that are robust to noise and accurately estimates the time locations of underlying transitions in the power system. The main advantage of the proposed technique is its early event detection, with respect to other traditional methods, because it performs sample-bysample evaluations. Moreover, the proposed technique does not require much computational effort, which means that the presented detection method is suitable for integration into the multifunction relay protection subsystems available in novel smart inverters.