Real-Coded Genetic Algorithm for Robust Design of UPFC Supplementary Damping Controller

Author(s):  
S. C. Swain ◽  
S. Mohapatra ◽  
S. Panda ◽  
S. R. Nayak

In this paper RCGA is used in Designing UPFC based supplementary damping controllers for damping low frequency oscillations in a single machine infinite bus power system. The detail investigations have been carried out considering the four alternatives UPFC based damping controller namely modulating index of series inverter (MB),modulating index of shunt inverter (ME),phase angle of series inverter (∂B) & phase angle of shunt inverter (∂E).RCGA is employed to optimize damping controller parameters. Simulation results are presented & compared with a conventional method of tuning the damping controller parameters to show effective of the proposed design approach.

Author(s):  
Aliyu Sabo ◽  
Noor Izzri Abdul Wahab ◽  
Mohammad Lutfi Othman ◽  
Mai Zurwatul Ahlam Mohd Jaffar ◽  
Hamzeh Beiranvand ◽  
...  

Generally, power systems experience a variety of disturbances that can result in low frequency electromechanical oscillations. These low frequency oscillations (LFOs) take place among the rotors of synchronous generators connected to the power system. These oscillations may sustain and grow to cause system separation if no adequate damping is provided. Power system stabilizers (PSSs) are one of the alternative devices used to solve this rotor oscillation problem. The major limitation of using PSSs at the excitation system of synchronous machine is that the conventional PSS is a permanent parameter type operating under a particular system operating condition, and its parameters are acquired through trial and error. An efficient way of operating the PSS has been by designing the PSS parameters using a powerful optimization procedure. However, designing PSS damping controller is a cumbersome task as it needs a comprehensive test system modeling and a heavy computational burden on the system. In this research, a novel, model-free neuro-fuzzy controller (NFC) is designed as the LFOs’ damping controller to substitute the traditional PSS system making the power system simple without complications in PSS design and parameter optimization. The proposed controller application implements the LFOs’ control without a linearized mathematical model of the system, as such it makes the system less complex and bulky. Single machine infinite bus (SMIB) test system was simulated in SIMULINK domain with the PSSs and with the proposed controller to compare the NFC effectiveness. The simulation outcome for the eigenvalue study with NFC stabilizer yields steady eigenvalues that enhanced the damping status of the system greater than 0.1 with decreased overshoots and time to rise via the proposed NFC process than with the conventional FFA-PSS. Similarly, the generator transient reaction also presents the ω and δ based on the time to settle was improved by 64.66% and 28.78%, respectively, via the proposed NFC process than with the conventional FFA-PSS. Finally, the conventional PSS was found to be complicated in its design, parameter optimization and less effective than the proposed controller for the LFOs’ control.


2015 ◽  
Vol 793 ◽  
pp. 242-246
Author(s):  
Arizadayana Zahalan ◽  
Noor Fazliana Fadzail ◽  
Muhammad Irwanto Misrun

This paper compares the performance of UPFC damping controller (, and ) to damp Low Frequency Oscillations (LFO) in power system equipped with UPFC based on Fuzzy Logic Power System Stabilizer (UPFC based FLPSS). The power system model was developed using linearized model of Phillips-Heffron Single Machine Infinite Bus (SMIB) and simulated in Matlab Simulink. The ability of each controller to damp LFO present in the rotor speed was monitored when the system being perturbed by small disturbances. The results obtained shown that UPFC controller had better performance to damp LFO compared to the other UPFC damping controllers as it had the lowest overshoot and less settling time.


Author(s):  
Soudamini Behera ◽  
Ajit Kumar Barisal ◽  
Nirmalya Dhal ◽  
Deepak Kumar Lal

AbstractThis paper presents an optimal design of a static synchronous series compensator (SSSC)-based controller for damping of low-frequency oscillations in multi-machine power systems. The proposed controller design problem is formulated to the optimization problem. The tuning of controller parameters can be obtained by employing a new hybrid differential evolution and particle swarm optimization (hDE-PSO) algorithm. To justify the effectiveness of the proposed SSSC-based damping controller, three-machine and four-machine power systems have been considered. The hDE-PSO algorithm outperforms in the damping of oscillations over DE and PSO algorithms. Various simulation results are presented and compared for different load disturbances like three-phase fault, load rejection and tripping of one parallel transmission line. The simulation results ensure the robustness of the proposed controller.


Author(s):  
Swathi Kommamuri ◽  
P. Sureshbabu

Power system stability improvement by a coordinate Design ofThyristor Controlled Series Compensator (TCSC) controller is addressed in this paper.Particle Swarm Optimization (PSO) technique is employed for optimization of the parameterconstrained nonlinear optimization problem implemented in a simulation environment. The proposed controllers are tested on a weakly connected power system. The non-linear simulation results are presented. The eigenvalue analysis and simulation results show the effectiveness and robustness of proposed controllers to improve the stability performance of power system by efficient damping of low frequency oscillations under various disturbances.


Author(s):  
M. Madanmohan ◽  
S. Pandey ◽  
A. Kushari ◽  
K. Ramamurthi

This paper describes the results of an experimental study to understand the influence of inlet flow disturbances on the dynamics of combustion process in bluff body stabilized diffusion flames of liquid petroleum gas and air. The results show the influence of weak disturbances created by the change in incoming pipe length on the amplitude of pressure oscillations and the phase angle between pressure and heat release. It is seen that the phase delay increases as the entry length increases. The rms value of pressure, however, generally falls with the increase in length. The phase angle is seen to be in the second quadrant, showing that the heat release oscillations damp the pressure oscillations. Therefore, the decrease in the phase angle results in the reduction in damping and hence an increase in pressure fluctuations. The dominant frequencies of combustion oscillations are found to be the low frequency oscillations, and the frequency of oscillations increases with a decrease in the inlet pipe length and an increase in the flow Reynolds number. It is suggested that such low frequency oscillations are driven by vortex shedding at the wake of the bluff body, which energizes the diffusion and mixing process.


2022 ◽  
Vol 12 (2) ◽  
pp. 589
Author(s):  
Abdul Waheed Khawaja ◽  
Nor Azwan Mohamed Kamari ◽  
Muhammad Ammirrul Atiqi Mohd Zainuri

Low frequency oscillations in large power systems may result in system instability under large disturbances. Power system stabilisers (PSS) play an effective role in damping these low frequency oscillations by injecting a modulating signal in the excitation loop of a synchronous machine. A new metaheuristic optimisation algorithm termed the sine cosine algorithm (SCA) was proposed for optimising PSS controller parameters to obtain an optimal solution with the damping ratio as an objective function. The SCA technique was examined on a single machine infinite bus (SMIB) system under distinct loading situations and matched with a moth flame optimisation technique and evolutionary programming to design a robust controller of PSS. The simulation was accomplished using a linearised mathematical model of the SMIB. The performance of a designed lead lag-controller of PSS was demonstrated using eigenvalue analysis with simulations, showing promising results. The dynamic performance was validated with respect to the damping ratio, the eigenvalue’s location in the s-plane and rotor angle deviation response to demonstrate system stability.


Author(s):  
Magdy A.S. Aboelela ◽  
Hisham M. Soliman

This paper focuses on the application of a robust Fractional Order PID (FOPID) stabilizer tuned by Genetic Algorithm (GA). The system’s robustness is assured through the application of Kharitonov’s theorem to overcome the effect of system parameter’s changes within upper and lower limits. The FOPID stabilizer has been approximated during the optimization using the Oustaloup’s approximation for fractional calculus and using the “nipid” toolbox of Matlab during simulation. The objective is to keep robust stabilization with maximum achievable degree of stability against system's uncertainty. This optimization will be achieved with the proper choice of the FOPID stabilizer’s parameters (kp, ki, kd, l, and d) as discussed later in this article. The optimization has been done using the GA which limits the boundaries of the tuned parameters within the permissible region. The calculations have been applied to a single machine infinite bus (SMIB)power system using Matlab and Simulink. The results show superior behavior of the proposed stabilizer over the traditional PID.


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