Ali Öztürk

Investigation of the control voltage and reactive power in wind farm load bus by statcom and SVC

In this study, the voltage stability of the bus load in various static and dynamic load systems that are fed by a wind farm has been examined. In the control of load voltage and reactive power, 10 MVAr static synchronous compensator (STATCOM) and static VAr compensator (SVC) is used. In the wind farm examined, Double Feed Induction Generator (DFIG) is used. In voltage and reactive power control, the results of time response and damping oscillation have been found using MATLAB / Simulink . The results achieved have proved that SVC and STATCOM yield good results when used in terms of voltage stability of the system.

Investigation of different load changes in wind farm by using FACTS devices

In this study, voltage, active power and reactive power variation of load bus were examined by Flexible AC Transmission Systems devices (FACTS) in grid-connected wind farm. In the system, FACTS devices, Static Synchronous Compensators (STATCOM), Static VAr Compensators (SVC), Static Synchronous Series Compensators (SSSC) and Thyristor Controlled Series Compensators (TCSC), were used. Also, dual feed induction generator (DFIG) was used as generator in the wind farm. This simulation study was done via Matlab/Simulink environment. According to different values of active and reactive loads at different times being attached to the system, shapes of load bus voltage, active power and reactive power variation were given, also the results were presented in tables. In the conclusion of this study, by means of FACTS devices that is used in the wind farm, instability was healed within a short time.

AN APPROACH FOR DESIGNING PASSIVE POWER FILTERS FOR INDUSTRIAL POWER SYSTEMS BY USING GRAVITATIONAL SEARCH ALGORITHM

Original scientific paper Harmonics are one of the important factors in determining the energy quality in power systems. Hence, eliminating or damping undesired harmonics is crucial in electrical power systems. Due to their low costs, Passive Power Filters (PPF) are widely used in industrial power systems to limit harmonics’ undesired affects. In this study, a new approach to design a PPF for power systems using heuristic Gravitational Search Algorithms (GSA) is proposed. Traditional Try and Error (TAE) method is, first, utilized to eliminate harmonics in our model power system. Then, GSA is adopted to minimize the effective current value of Point of Common Coupling (PCC) in the same model system. Our results yield that our proposed method with GSA eliminates the harmonics effectively.

THE EVALUATION OF MUNICIPAL SOLID WASTES AS ENERGY SOURCE

The waste combustion is a burning method in which wastes are burned under controlled conditions to produce energy under optimal conditions with a reduction in waste volume of 100-1000 times. Although this method is preferred due to the high energy gain, it is criticized in some societies due to the formation of some toxic combustion products and gases and high initial investment cost. The thermal processing or pyrolysis method is a method that brings out innovative technologies and designs around the world because of environmental factors as well as economic improvements. Municipal solid wastes can be disposed by the pyrolysis method which gained popularity in recent years, by producing economical value of the obtained thermal processing liquid and syngas and also the electricity can be produced during the process. In this study, the methods aforementioned in terms of energy production from municipal solid wastes were examined and an evaluation was made for Turkey .

Active power loss minimization in electric power systems through chaotic artificial bee colony algorithm

Original scientific paper Reactive power optimization (RPO) is a major field of study to ensure power systems for operating in a secure and economical manner. RPO can be used for decreasing of active power losses, voltage control, and for the optimization of the power coefficients in power systems. The non-linear power loss function is used as an object function that will be minimized. In this study Chaotic Artificial Bee Colony (CABC) algorithm is used to minimize the active power loss of power systems. Chaotic maps such as logistic map and Henon map are used against the random number generator. CABC is applied on the IEEE6-bus and IEEE 30-bus test systems and the results are shown. Accordingly, the results have been evaluated and observed that the stability critical values found by CABC can be used to produce good potential solutions. Simulation results are promising and show the effectiveness of the applied approach.

Investigating voltage stability problem in the electrical power system using gravitational search algorithms

This study aims to utilize the Gravitational Search Algorithm (GSA) to find the optimal values of the proportional integral derivative (PID) controller parameters to control the automatic voltage regulator (AVR). GSA is categorized as a heuristic algorithm. In finding the optimal values, we try to minimize the performance index also called the error in the closed loop control diagram. We observed and compared the three different situations of the error, namely the integrated absolute error (IAE), the integral of squared error (ISE), and the integral time absolute error (ITAE). We, then, employed a conventional Ziegler-Nicolas Method (ZNM) to find the optimal values under the same conditions with GSA. The values obtained through both methods are compared at the end. We show that the proposed method using GSA has a better performance than ZNM in terms of settling time, oscillations and overshoot. We also compared our results with the ones obtained through Genetic Algorithms (GA). Similarly, our method performs better.

Speed control of wind turbine rotor using genetic algorithm

In wind farms, rotor speed control of generator is essential to generate appropriate electric energy. In this study, squirrel cage induction generator (SCIG) is used and its rotor speed is controlled with Genetic Proportional-Integral (GPI) method. Determination of PI coefficients providing SCIG to operate reference rotor speed promptly is obtained with Genetic Algorithm (GA) known as an optimization method. In addition, sensorless control of rotor speed is carried out with field oriented control (FOC). To do this purpose, the transfer function of rotor speed control of induction machine is created and employed in simulation model. Used in this control, PI coefficients, firstly, are obtained with a classical method called Ziegler-Nichols Method (ZNM) and then is obtained with GA. Wind turbine (WT) model created with Matlab/Simulink are used to operate the system simulation for these different methods which determine the PI coefficients. The system simulation of the results for ZNM and GA are compared. It is clearly seen that the results which are operated with PI coefficients calculated by GA is better than the others in the respect of reaching time to reference speed and determination.

Control of DC link voltage unit with Fuzzy Logic Controller in the wind farm

In this study, the analysis of wind farm that has Double Feed Induction Generator (DFIG) with Fuzzy Logic Controller (FLC) in its operation connected to the grid is realized. In wind farm, DC voltage control is modeled with FLC. Bus voltages that are connected to grid, load bus voltage, DC link voltage, active and reactive power variations of wind farm are examined. Simulation results are demonstrated with figures by Fuzzy Logic Controller (FLC)-Proportion Integrate (PI) comparison. As a result of the studies, it is observed that FLC makes the system stable in a shorter time than PI.

Determination of voltage stability critical loading values using Simulated Annealing

In this study, critical bus values in a power system are determined by using simulated annealing (SA) algorithm. As an example, a power system which contains the slack, generator and load buses is analyzed. Firstly, load value of the selected load bus is augmented step-by-step and load flow analysis is done for each case. This process is continued till there is no solution and in this way the critical bus values that are limit values of voltage stability are obtained. Secondly, by using SA algorithm, critical values are directly determined without augmenting the load of the selected load bus. The results show that the critical values can be easily determined using SA.

GENETİK ALGORİTMA KULLANILARAK GÜÇ SİSTEMLERİNDE OPTİMAL ÇALIŞMA ŞARTLARININ BELİRLENMESİ

Bu calismada optimizasyon yontemlerinden biri olan Genetik Algoritma (GA) ile elektrik guc sistemlerinde optimum calisma kosullari belirlenmistir. Calismanin ana hedefi iletim hatlarinda meydana gelen aktif guc kayiplarinin minimum olmasini saglayacak yuk baralarinin gerilim genlik degerlerinin belirlenmesidir. Ornek olarak 5 barali bir sistem ele alinmis ve bu sistem uzerinde hem GA hem de Newton-Raphson (NR) guc akisi yontemi kullanilarak yuk baralarinin calisma gerilim degerleri belirlenmistir. Bu degerler kullanilarak Statik VAR Kompanzator (SVC) ile reaktif guc kompanzasyonu yapilmistir. Elde edilen sonuclar, GA ile calisma kosullarinin belirlenmesi durumunda aktif guc kayiplari minimize edileceginden ciddi oranda ekonomik kazanc ve enerji tasarrufu saglanacagini ortaya koymaktadir.