Enhancement of Load Frequency Control concerning High Penetration of Wind Turbines Using Intelligent Control Technique

Modern day power systems are divided into various areas. The transmission lines that connect an area to its neighboring area are called tie-lines sharing power between two areas. Automatic Generation Control (AGC) as the name signifies it regulates the power flow between different areas while holding the frequency constant. Frequency control as a major function of automatic generation control is one of the important control problems in electric power system design and operation, and is becoming more significant today due to the increasing size, changing structure, emerging new uncertainties, environmental constraints, and the complexity of power systems. Due to the rising penetration of the renewable energy sources modern Load-frequency control (LFC) systems should be able to handle complex multi objective regulation optimization problems. Wind power fluctuations impose additional power imbalance to the power system and cause frequency deviation from the nominal value. A decentralized PSO based Fuzzy Logic Controller is considered for Load Frequency Control (LFC) to maintain frequency, net power interchanges with neighboring control areas and power allocation among units at economically desired values. The PSO based fuzzy controller was used as LFC scheme, where PSO technique was used to optimize the membership functions of fuzzy logic. As further modification fuzzy-PID controller with Genetic Algorithm and Improved Particle Swarm Optimization are used for the of improvement of frequency deviation and tie line power changes. Here both the algorithms are used to get optimized values of gain constants for Fuzzy PID controller. The resulting signal from Fuzzy PID controller is used to control the system. The work is done on 9 bus system and same is implemented on higher bus system. INTRODUCTION Fluctuating nature of the wind power creating introduces several challenges to the reliable operation of the power system .As the power system dependency on wind power increases wind power generation will have to contribute with services normally delivered by conventional plants. In such power system wind power generation will have to provide fast frequency regulating capability, reliable, deterministic and repeatable frequency response to support the grid. Dynamic behavior of a power system in the presence of wind power generation might be different from conventional power plants. The power outputs of such sources are dependent on weather conditions, seasons, and geographical location. When wind power is a part of the power system, additional imbalance is created when the actual wind power deviates from its forecast due to wind velocity variations. So, scheduling conventional generator units to follow load (based on the forecasts) may also be affected by wind power output Banakar et al.(2008). Furthermore, the effect of wind farms on the dynamic behavior of power system may cause a different system frequency ISSN: 2347-1964 Online ISSN: 2347-1875 Print Transactions on Engineering and Sciences www.techscripts.org 1 Tech scrip ts response to a disturbance event (such as load disturbance).Since, the system inertia determines the sensitivity of overall system frequency. The main problems with wind energy are the following  Highly fluctuating wind generation can have consequences in terms of frequency stability  Frequency variations will make sudden changes in generated power can lead to unacceptable output changes  Difficulties in forecasting energy production make network management More Challenging Load Frequency Control (LFC) techniques are needed nowadays. Load Frequency Control (LFC) synthesis in power systems has a long history and its literature is voluminous. The conventional LFC (usually PI controllers) designs are suitable for working at specific operating points, and they are not more efficient for modern power systems, considering increasing size, changing structure, emerging renewable energy sources, and new uncertainties. Most of conventional LFC synthesis methodologies provide model-based controllers that are difficult to use for large-scale power systems with nonlinearities, and uncertain parameters. Intelligent LFC schemes are introduced to this environment to be more adaptive/flexible than conventional ones.