DE and PSO optimized PID Controller for Automatic Generation Control of Multi-Source power system

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GRD Journals | Global Research and Development Journal for Engineering | International Conference on Innovations in Engineering and Technology (ICIET) - 2016 | July 2016

e-ISSN: 2455-5703

DE and PSO optimized PID Controller for Automatic Generation Control of Multi-Source Power System 1P.

Nagajothi 2Dr. K. Gnanambal 1 PG Scholar 2Professor 1,2 Department of Electrical and Electronics Engineering 1,2 K.L.N. College of Engineering, Pottapalayam - 630 612, Tamilnadu, India. Abstract There are several methods are available for Load Frequency Control in interconnected power system. This paper proposes an optimized PID controller by DE tuning for AGC of two area power system. The gain parameters of the PID controller are optimized by commissioning DE and PSO technique. In this paper ISE criterion is used as a performance index. The action of this proposed power system with optimal tuned PID controller provides a satisfactory balance between frequency overshoot and transient oscillations with minimum steady state error. A comparative study on tuned values has been presented to verify effectiveness between DE and PSO method. The simulation results reveal the effectiveness of the designed system in terms of reduced settling time and oscillations with tuning of DE. MATLAB/SIMULINK was used as simulation tool. Keyword- AGC, Differential Evolutionary algorithm Hydrothermal Power system, ISE,PID controller, PSO algorithm __________________________________________________________________________________________________

I. INTRODUCTION The power system has the main aim of Continual matching of load demand and power generated. The output power from the power system should provide a certain level of consistency in frequency and magnitude of the voltage. Thus, maintaining power system stability is the main challenging issue in recent decades due to frequent variation in load demand. Power system stability means to remain in a condition of operating stability under normal working conditions and to regain an adequate state of equilibrium after disturbance occurs. A power system operator has to continuously monitor the health of a power system and performs control actions when needed. The successful operation of an interconnected power grid is maintaining the system frequency and interchanged power at their respective scheduled power levels. An interconnected power system basically consists of generating units, the transmission lines and the loads[1]. While operating generators there may be some disturbances such as sustained oscillations in the speed or periodic variations in the torque. This kind of disturbances may result in voltage or frequency fluctuation. This may affect the other parts of the interconnected power system. All these disturbances are called as faults[1]. The generators to lose synchronism while fault occurs. With these factors in mind, the primary condition for a power system with stability is synchronism. Besides this condition, there are other important conditions such as steady-state stability, transient stability, harmonics and disturbance, the collapse of voltage and the loss of reactive power[2]. In a power system, there are two types of control mechanisms available to achieve the acceptable voltage and frequency profile. Automatic Voltage Regulator is a control method used to balance the reactive power (i.e,Voltage) and Automatic Generation Control is used to balance the real power (i.e,Frequency) in an interconnected power system network. The main aim of AGC is to minimize the area transient frequency deviations, tie line power interchange and to ensure that steady state errors maintain with zero level[2]. According to Indian Electricity Grid Code(IEGC) if rated system frequency is 50 Hz and the target range for frequency control is should be 49.0-50 HZ, the statutorily acceptable limits are 48.5-51.5 Hz. However, the users of power system change the loads more frequently. This gives the sudden mismatch between the generation and load. This mismatch power causes a change in generator speed and consequently the frequency variation from its nominal value. So the control mechanism is necessary to cancel the random load changes and to keep the frequency at the nominal value. This article is ordered as follows. Section 2 presents a test power system model with their time constant functions and PID controller general structure. We addressed a review in Section 3 which has tuning method of PSO and DE algorithms. In Section 4, the comparison between PSO tuned PID controller and DE tuned PID controller parameters are given which shows the effectiveness of PSO tuned PID controller parameters of an AGC system.

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