An Integrated Method for under Frequency Load Shedding Based on Hybrid Intelligent System-Part I: Dynamic Simulation

Security is one of the most vital requirements in the operation of power systems. Frequency is a reliable indicator to determine instability condition in power system, i.e. the stability of power system is closely dependent on the value of system frequency. Under Frequency Load Shedding (UFLS) is one of the most important protection systems as in many cases it is the last action taken to prevent a system blackout after a serious disturbance occurs in power system. The first part of this two part paper presents various factors in modern power systems which have significant contribution on Under Frequency Load Shedding (UFLS). A high-order multi-machine frequency response model is utilized as it the best strategy of power system dynamic simulation. Classification of modern power system components and using an equal unit for each class is proposed in this work. The results show that ANN models can also be implemented as well as a fast dynamic simulator of electric power system. This assessment includes a review of significant researches on power system dynamic simulation and frequency response model leading to an integrated UFLS system design.