Improvement of Small Signal Stability Early Warning Based on OAPID and CBR Theory

To assist dispatchers to on-line monitor small signal stability of power grid, this paper proposed an artificial intelligent method-Case-Based Reasoning(CBR) theory to predict small signal stability based on measurement data of wide area measurement system (WAMS). Oscillatory active power increment distribution (OAPID) was introduced to improve the prediction accuracy. The designing process of small signal stability early warning for a regional power grid was elaborated here, which could achieve the following desired function: If non-oscillation occurs, it may prevent the system from oscillation; and when oscillation happens, it could appropriately reschedule operation mode to improve the small signal stability. Case study and test of a regional power grid verify that the approach proposed in this paper was simple, feasible and effective. It´s helpful for dispatchers´ rapid decision when emergency occurred.