Optimized Load Frequency Control Strategies for Various Power System Models

Abstract

Power systems are complex electrical networks that have great relevance in the eco­ nomic development as the entire world depends on the electric power supply for all life activities. For the stable operation of electric power systems, several protection and con­ trol techniques are necessary. Among different controls available, the frequency control is the most time-consuming control mechanism of power systems due to the involvement of mechanical parts. Hydropower is considered as the most balancing source of power generation in a power system and thereby ensuring the sufficiency of power production over the consumption while keeping the grid frequency stable. Ina power system hydro power forms an important energy resource in active power balancing and thereby control­ ling the system frequency. The power system inertia provided by synchronously rotating masses of hydro power systems have a major part in maintaining the system stability and frequency control. New challenges have emerged with the integration of renewable en­ ergy resources especially wind turbines. The output of wind turbine generators varies in random fashion with the wind speed variations and this results in fluctuations in sys­ tem frequency thereby a total decline in the frequency control mechanism of the whole power grid. Therefore revision of existing load frequency control strategies is required for including the increased share of renewable energy resources in interconnected power systems. newline newlineThe Load Frequency Control (LFC) is a matter of interest in power system opera­ tion and is one of main research areas. LFC addresses the problem of controlling the system frequency in response to the disturbances. A well acknowledged solution to this problem is the feedback stabilization, where the Linear Quadratic Regulator (LQR) based controller computes the feedback gain K, from the known system parameters and im­plements the control, assuming the availability of all the state variables.