Desain Kontroler Tunggal untuk Meredam Osilasi Multi Frekuensi pada Sistem Skala Besar

Paper ini menjelaskan tahapan desain kontroler tunggal yang ditujukan untuk meredam lebih dari satu frekuensi osilasi yang terjadi pada suatu sistem skala besar termasuk metoda- metoda yang dikembangkan pada setiap tahapannya. Metoda ini dikembangkan terutama sangat berguna untuk desain kontroler pada sistem yang sangat besar serta memiliki multi frekuensi osilasi dan multi variabel state sebagai kandidat sinyal umpan Balik. Pada tahap awal, dilakukan pemetaan frekuensi osilasi yang muncul untuk kemudian dipilih bebe- rapa frekuensi sebagai target yang akan distabilkan. Selanjutnya, pengaruh masing-masing variabel state terhadap frekuensi target dianalisis dengan menggunakan faktor partisipasi. Variabel-variabel state yang dominan akan dipilih sebagai kandidat sinyal umpan Balik. Jalur umpan Balik didapat dengan menginjeksikan sinyal kontrol ke variabel state tertentu. Se- lanjutnya keefektifan jalur umpan Balik dianalisis dengan konsep residu. Jalur umpan Balik dengan nilai residu terbesar merupakan pilihan terbaik untuk meredam frekuensi target. Perhitungan kontroler dikembangkan berdasar kontrol robust dan akan diaplikasikan pada sistem riil ketenagalistrikan dalam level simulasi dengan Simulink-Matlab

Applying of Double Seasonal ARIMA Model for Electrical Power Demand Forecasting at PT. PLN Gresik Indonesia

The prediction of the use of electric power is very important to maintain a balance between the supply and demand of electric power in the power generation system. Due to a fluctuating of electrical power demand in the electricity load center, an accurate forecasting method is required to maintain the efficiency and reliability of power generation system continuously. Such conditions greatly affect the dynamic stability of power generation systems. The objective of this research is to propose Double Seasonal Autoregressive Integrated Moving Average (DSARIMA) to predict electricity load. Half hourly load data for of three years period at PT. PLN Gresik Indonesia power plant unit are used as case study. The parameters of DSARIMA model are estimated by using least squares method. The result shows that the best model to predict these data is subset DSARIMA with order ([1,2,7,16,18,35,46],1,[1,3,13,21,27,46])(1,1,1)48(0,0,1)336 with MAPE about 2.06%. Thus, future research could be done by using these predictive results as models of optimal control parameters on the power system side

Gabor-based Face Recognition with Illumination Variation using Subspace-Linear Discriminant Analysis

            Face recognition has been an active research topic in the past few decades due to its potential applications. Accurate face recognition is still a difficult task, especially in the case that illumination is unconstrained. This paper presents an efficient method for the recognition of faces with different illumination by using Gabor features, which are extracted by using log-Gabor filters of six orientations and four scales. By Using sliding window algorithm, these features are extracted at image block-regions. Extracted features are passed to the principal component analysis (PCA) and then to linear discriminant analysis (LDA). For development and testing we used facial images from the Yale-B databases. The proposed method achieved 86–100 % rank 1 recognition rate

Power Quality Analysis of Integration Photovoltaic Generator to Three Phase Grid under Variable Solar Irradiance Level

Objective of research is to analyze the influence of solar irradiance and integration of  photovoltaic (PV) generator to power quality of three phase grid on the constant temperature and load, based on changes in some level of integration of  PV generator. Power quality aspects studied are fluctuation or changing, and harmonics of voltage and current on eight scenarios PV generator connected to three-phase grid, using passive filter circuit model double band pass (double tuned). Research shows that voltage and current values on the PCC bus before use double tuned passive filter on the condition only connect single generator is still stable. However, if the PV generator connected to the three phase grid, amounted to more than one generation, voltage and current grid becomes unstable (fluctuation). At the level of solar radiation remains, the greater number of PV generators connected to the grid three-phase, then the values of voltage and current THD increases. At the level of solar irradiance increases, average THD of voltage and current grid also increased. Avarage THD of voltage and current grid is reduced after double tuned passive filter installed. Therefore, double tuned passive filter able to improve profile of voltage and current THD grid as a result of the integration of a number of PV power generators in three-phase grid according IEEE Standard 519-1992. Simulation and analysis of this research use Matlab/Simulink.

Matlab/simulink simulation of unified power quality conditioner-battery energy storage system supplied by PV-wind hybrid using fuzzy logic controller

This paper presents performance analysis of Unified Power Quality Conditioner-Battery Energy Storage (UPQC-BES) system supplied by Photovoltaic (PV)-Wind Hybrid connected to three phase three wire (3P3W) of 380 volt (L-L) and 50 hertz distribution system. The performance of supply system is compared with two renewable energy (RE) sources i.e. PV and Wind, respectively. Fuzzy Logic Controller (FLC) is implemented to maintain DC voltage across the capacitor under disturbance scenarios of source and load as well as to compare the results with Proportional Intergral (PI) controller. There are six scenarios of disturbance i.e. (1) non-linear load (NL), (2) unbalance and nonlinear load (Unba-NL), (3) distortion supply and non-linear load (Dis-NL), (4) sag and non-linear load (Sag-NL), (5) swell and non-linear load (Swell-NL), and (6) interruption and non-linear load (Inter-NL). In disturbance scenario 1 to 5, implementation of FLC on UPQC-BES system supplied by three RE sources is able to obtain average THD of load voltage/source current slightly better than PI. Furthermore under scenario 6, FLC applied on UPQC-BES system supplied by three RE sources gives significantly better result of average THD of load voltage/source current than PI. This research is simulated using Matlab/Simulink

Power-Flow Development Based on the Modified Backward-Forward for Voltage Profile Improvement of Distribution System

Unbalanced three-phase radial distribution system has a complex problem in power system. It has many branches and it is sometimes voltage profile’s not stable at every end branches. For improvement of voltage profile, it can be performed by penetrating of a distributed generation models. Information of voltage profile can be gained by study of power flow.  The Modified Backward-Forward is one of the most widely used methods of development of power flow and has been extensively used for voltage profile analysis. In this paper, a study of power flow based on the Modified Backward-Forward method was used to capture the complexities of unbalanced three phase radial distribution system in the 20 kV distribution network in North Surabaya city, East Java, Indonesia within considering distributed generation models. In summary, for the informants in this study, the Modified Backward-Forward method has had quickly convergence and it’s just needed 3 to 5 iteration of power flow simulation which’s compared to other power flow development methods. Distributed Generation models in the modified the modified 34 BUS IEEE system and 20 kV distribution network has gained voltage profile value on limited range. One of the more significant findings to emerge from this development is that the Modified Backward-Forward method has average of error voltage about 0.0017 % to 0.1749%

Prediction of Critical Clearing Time of Java-Bali 500 kv Power System Under Multiple Bus Load Changes Using Neural Network Based Transient Stability Model

A transient stability model based on back propagation neural network is used to analyze transient stability of Java-Bali electricity system, especially in calculating the critical clearing time. The real and the active load changes on each bus that shows the real load pattern of the system used as neural network input, while the target is the Critical Clearing Time (CCT). By using the load pattern as input, it is hoped that the robustness of the proposed method against load changes at multiple bus can be achieved. Data of target critical clearing time used for the training was calculated from the concept of One Machine Infinite Bus (OMIB), by reducing the multi-machine system using a combination of methods of Equal Area Criterion (EAC) through the Trapezoidal method and the Runge-Kutta 4th order method. To analyze transient stability, a three phase ground fault was conducted at one bus and assumed not changed during the simulation. The proposed method will be implemented at Java-Bali 500 kv power system. The simulation results show the calculation of critical clearing time from the proposed method has a minimum error of 0.0016% and a maximum error of 0.0419% compared with CCT by OMIB

Influence Types of Startup on Hydrothermal Scheduling

The energy costs of a power plant consist of startup cost and cost of power usage. In contrast to the existing literature, this study introduces at startup cost based on the duration of thermal power plant downtime. The approach of startup cost function in this research is done by using startup type. Startup of a steam power plant depends on its condition. Generally, there are three types of startup the power plant when the turbine temperature is still very high, i.e. hot start, very hot start and very-very hot start. This paper uses multistage optimization to solve the problem of hydrothermal scheduling with including the startup type cost in the objective function. The simulation results showed operating cost savings when the objective function for optimization also consider the cost based on startup type i.e. when compared with the optimization result which the objective function does not take the cost of startup type

Biogas Production from Vegetables and Fruit Wastes Using Anaerobic Floating Bioreactor

Markets and supermarkets are one of the pillars of the country's economy, besides that, they are also the biggest contributors to vegetable and fruit waste which can cause various environmental problems. Therefore, the abundance of vegetable and fruit waste produced by markets and supermarkets can be utilized as environmentally friendly alternative energy, namely biogas. This study aimed to determine the effect of organic loading rate (OLR) on biogas production and gas composition in a continuous anaerobic floating bioreactor using mixed vegetable and fruit waste. A 40-l anaerobic floating bioreactor was utilized and the hydraulic retention time was 10 days; one kg of vegetable and fruit wastes at a 1:1 mass ratio was added with water to 4 l and introduced during 25 days; the daily biogas production was collected in a floating drum and measured as volume. The maximum biogas yield was 0.0452 m3/kg, achieved using the OLR of 0.0125 kg/l.day.  The use of OLR of 0.0250, 0.0375 and 0.0500 kg/l.d reached biogas yields of 0.0435, 0.0282, and 0.0163 m3/kg, respectively. The composition of the maximum biogas yield was 68.17% CH4, 19.34% CO2, 1.85% H2S, and 0.64% NH3.