Frequency Stability-Based Penetration Limit Evaluation of Variable Energy Resources in Power Systems for Online Application

While aiming to increase the dispatch of variable energy resources (VER) during the operation of a power system, the stability of the power system should be maintained, which can be realized by evaluating the penetration limit of the VER. This paper proposes a method for evaluating the penetration limit of VER. When a disturbance such as a generator trip occurs, the frequency stability depends on the inertia energy secured by generators, the characteristics of the primary frequency response, and the load response, which would change owing to an increase in the VER of the power system. In the proposed evaluation method, the frequency response performance of the power system is analyzed based on the historical operation data, and the penetration limit of VER is evaluated by applying the frequency criterion to maintain the frequency stability of the power system. Therefore, the potential penetration limit of VER can be estimated depending on the operating conditions. In addition, the effectiveness of the proposed evaluation method is verified by comparing the simulation results based on the Korean power system model-based simulation, and the online application is evaluated by applying it based on the real system operation data.