Nanang Hariyanto

Spatial short-term load forecasting using grey dynamic model specific in tropical area

Grey systems theory is the one of the most important research of uncertainty system, developed into a set of address information is not a complete systems. This theory realizes the correct description and effective supervision in operation action and evolution law of system, mainly through generating, exploring and extracting valuable information from a little part known information to predict the unknown information value. Dynamic forecasting model is needed due to the uncertain nature of the load predicting process specifically when load changes is correlated to the tropical temperature effect in Indonesia. A grey predicting approach is implemented in this paper to solve dynamic short term load forecasting in local substations of the Indonesian high voltage grid, as provided by Jawa Bali Load Control and Operator Center (PLN P3B Gandul). Traditional GM(1,1) model is presented to compare with the GM(1,2) for weekday and weekend load conditions refer to the temperature variation pattern during the year 2009. GM(1,2) model denotes the relationship of hourly load demand affected to the tropical climate change variable, i.e. local ambient temperature. The daily load curve for Cawang and Cibatu substations, as representing Jakarta area, was used to validate the models. Typical combination Grey model specified in tropical climates was implemented to capture the load changes correlated to the temperature effect in each particular season, The model adequacy and weekly forecasting result had indiced a good grade in error diagnostic checking (MAPE) in each location.

A genetic algorithm approach determining simultaneously location and capacity distributed generation in radial distribution system

Network reliability of distribution system is one of the key performance indices to be realized with many efforts. Installing Distribution Generation (DG) on radial distribution network closer to the customers is one of the efforts, which can improve the indices. This paper will present a GA method to determine the best location and capacity of DG placement with minimum power losses as an objective function to achieve optimum result. By DG placement in the network, except improve the voltage profile and power losses also the reliability indices such as SAIDI, SAIFI and EENS. Therefore the reliability will experience an improvement than before. For calculating and analyzing the reliability indices it uses ETAP 12.6 software which is separate analysis with determine the position and capacity optimization method. This concept will realize by simulating in the 132 bus radial distribution system and considering into two schemes, the base load scheme and full load scheme.

New probabilistic approach for identification event severity index due to short circuit fault

In this paper, it is introduced a new approach to identify bus voltage severity profile due to short circuit fault at a certain point in a distribution power system. Short circuit causes voltage decrement for duration of time related to opening time of a relay. Data containing 2 variables, depth and duration of voltage sag due to short circuit faults on every buses, are generated. Subsequently, these data from all of buses will be clustered using K-means Clustering. Clustering data will produce center clusters and cluster membership. To be able to perceive voltage sag severity, center clusters will be converted to Event Severity Index which explains severity of a voltage sag event based on CBEMA-ITI Curve. Data of a certain bus which undergoes voltage sag events will be classified based on its cluster membership or center cluster. Thus, it will be obtained frequency of events that are classified into particular clusters; how many events that is classified into particular clusters. In order to observe data well, it is better to present it making use of histograms.

Wind speed calculation by using electrical output and wind turbine power curve

Measurements of wind speed usually done by using anemometer, these data can be used as a reference signal to the wind turbine control, or it can be used also for mapping the wind energy potential. Recently, the use of anemometer on wind turbines are often eliminated because of technical and cost reasons. This paper describes an alternative method to determine the upstream wind at the wind turbine without using the anemometer, but using only the electrical output (current and voltage) and the power curve data provided by the wind turbine manufacture. Further, the power curve is mathematically modeled by polynomial interpolation method so that the wind speed equation as a function of power can be determined.

Fix series capacitor for increasing power transfer on transmission 150 kV at Sumatera interconection system

The power transfer restrictions on the transmission lines 150 kV in Sumatera Interconnection System caused electric power generated by the power plant with lower cost in fuel at Southern Sumatera cannot be optimally delivered to the load centers in Northern Sumatra. One of technical solution that is expected to solve this problem is fixed series capacitor installation in tie line Lubuk Linggau - Bangko. It is connecting Southern Sumatera and Northern Sumatera through Central Sumatera. Simulation carried out with Digsilent 12.0. Simulation results indicate a maximum transfer can be improved, however system stability is become lower but still at safe limits.

Characteristic study of three-phase AC electric arc furnace model

The electric arc furnace can cause voltage flicker and produce harmonics that can impact the power system. This is due to the characteristics of electric arc furnace as a nonlinear load. Designing an electric arc furnace model is intended to study the characteristics of the electric arc furnace and its impact to the power system. The voltage flicker model of Chuas Chaotic Circuit and differential equations of the arc length will be used in the modeling of the electric arc furnace. In accordance with the purposes of this study, the model of electric arc furnace will be applied to the design and placement plan in the power system. Before applying the electric arc furnace model to the power system, the v-i characteristic of electric arc furnace, harmonics, flicker, and other preinstallation requirements will be studied as mentioned in the grid code.

Underfrequency load shedding scheme using generator coherency approach

In power system operation, frequency issue caused by power imbalance between generation and load can occur in power system. If generation is smaller than load, system frequency will drop. When generation deficiency is too large, system frequency will decrease significantly which can lead to system blackout. To solve this frequency issue, proper underfrequency load shedding and islanding scheme is essential to prevent further deviation of system frequency from its nominal frequency. In this research, conventional underfrequency load shedding and islanding scheme using generator coherency approach are designed for Southern Sulawesi system, one of power system in Sulawesi, Indonesia. Southern Sulawesi system is not too large with peak load of about 800-1000 MW therefore easier to analyze performance of the method used in this research. The simulations were performed using DIgSILENT PowerFactory. Underfrequency load shedding and islanding scheme obtained can be applied to all scenarios simulated in this research with good performance.

Implementation of power oscillation damping function in STATCOM Controller

STATCOM is reactive power compensator based upon a voltage source converter which uses power electronic devices with turn-off capability as switching devices. Its main function is to support bus voltage of which it is connected to the system by providing quick response to supply or absorb reactive power. For damping power oscillations purpose, it is required to employ power oscillation damping (POD) function wherein its output is summed to voltage reference as input of STATCOM. This paper focuses on implementing POD function in STATCOM control to damp interarea oscillations mode. Kundurs two area system with 11 buses and four generating units is used. Each generating unit uses fast exciter and the system presents three modes of oscillations, that is, local mode area 1, local mode area 2 and interarea mode. The power oscillations can then be damped by STATCOM Controller which is equipped with the POD function. The effectiveness of controller design is assessed based on time domain simulation using PSCAD software.

The use of Markov chain method to determine spare transformer number with 3-criteria parameters

System failure cannot be avoided, one of the solutions to maintain system reliability is with the existence of spare equipment, and however the number of spare equipment will increase the investment costs. Currently, spare transformer calculation study only considers one criteria in state transition model, a new model which considers other criteria such as transformer condition and transformer loading is needed. Java Bali 500/150 kV Transformer case study was used in order to show the usefulness of the proposed model.

Optimal switch placement in radial distribution system based on reliability worth analysis

Reliability improvement is one of the important things for electrical distribution company. By using some devices such as recloser and sectionalizing switch will reduce the amount of interrupted load during the fault. However, improvement of reliability need a cost, it can be said that reliability of the system and investment cost is comparable. In this paper, reliability of distribution network is assessed by considering reliability cost worth. A methodology based on cost worth analysis for optimal switch placement in distribution system network is proposed. This paper study has been conducted on the existing of Indonesian radial electrical distribution network.