Frequency Response Assessment of Electricity Grid by Regression Analysis

The Indian grid is stable in terms of frequency deviation since the majority of the grid is supported by rotating machines with high inertia. Only 25 to 30% of the grid is powered by renewable energy sources. But their contribution is expected to increase rapidly as the demand is increasing and the concept of sustainable and green energy is becoming strong. Eventually, the inertia providers in the system become largely replaced by renewable sources. The faster response of the inverter based renewable sources may reduce the time gap required to take necessary control actions during a disturbance. Therefore a better prediction of the system frequency response before an event is necessary to take faster control actions. This paper proposes a method to predict the frequency response of a grid-connected system integrated with wind and solar-based generation. A regression-based method applied to the test system which estimates the rate of change of frequency from several factors such as the size of the disturbance, percentage of thermal generation, control area response, and generation response is presented here.