Sulawesi System Research Articles

Analisis Penentuan Lokasi Gangguan Hubung Singkat Pada Saluran Transmisi Di Sulawesi Tenggara

The electricity system often experiences disturbances, especially short circuit disturbances on transmission lines. This short circuit disturbance is caused by various things such as lightning surges, fallen trees, animals, and other conditions. The interconnected Southeast Sulawesi power system cannot be separated from this short circuit problem. Therefore, determining the location of this short-circuit fault must be done quickly so that the cause of the disturbance can be immediately identified. This study aims to analyze the determination of the location of short circuit faults using the Takagi Method. Simulations were carried out using ETAP 16.0.0 software to see the condition of the Southeast Sulawesi system power flow. This Takagi method analyzes the location of the disturbance using the conditions before and after the disturbance occurs based on the recorded data at the substation. The results of the analysis carried out on the Southeast Sulawesi transmission line show that the percentage of accuracy in determining the location of a single-phase short-circuit fault to ground using the Takagi method is better, with a distance difference of 0.368-0.581 km (1.49%) when compared to the reading results on recordings of 10,173-9,960 km (31.58%) from the fault location occurred after inspection of the Lasusua-Kolaka transmission line. Disturbances on lines 1 and 2 Kolaka-Lasusua produce an error value of 1.533 km (9.24%) and 1.547 km (9.32%) when compared to fault locator readings of 3.212 km (19.36%) and 1.812 km ( 10.92%). Meanwhile, the Unaaha-Kolaka transmission line produces a distance difference of 0.709 km (3.29%) when compared to the fault locator reading of 4.323 km (20.12%). The results of the power flow simulation produce an installed generating capacity of 188 MW, a total active power of 116.780 MW and a reactive power of 29,944 Mvar. Thus, it can be concluded that the Takagi Method has a better accuracy value in reading fault locators.

Power Flow Analysis in N-1 Contingency Conditions Due to the Entry of Renewable Power Plants in the Sulselrabar System

Contingency analysis on a 150 kV network aims to see the network's reliability against interference. Contingency is a scheme for releasing one element of the generating unit or transmission line (N-1), which will affect the performance and reliability of the electric power system. Power flow analysis in an electric power system is an analysis that reveals the performance of an electric power system and the flow for certain conditions when the system is working. The analysis was carried out using the ETAP 16.00 software. The method used was the newton raphson to calculate the load flow in the N-1 contingency condition. From the results of the study, it can be seen that the power flow occurs in each channel of the 150 kV system in the South Sulawesi system. When conducting a contingency analysis of N-1 by removing the load on the middle lane of South Sulawesi, namely Maros and Sidrap, a voltage change occurs, increasing buses experiencing critical and marginal voltage conditions. This happens because of the sudden release of essential loads, so over or under voltage appears on the bus.

Optimal economic dispatch using particle swarm optimization in Sulselrabar system

In this study, a particle swarm optimization (PSO) is proposed to optimize the cost of generating thermal plants in the South Sulawesi system. The study was con ducted by analyzing several methods using the lagrange and ant colony optimization (ACO). PSO algorithm converges on the 11th iteration algorithm with the lowest generation cost obtained, which is Rp129687962.17/hour. While the ACO algorithm converges on the 34th iteration with a generation cost of Rp131,473,269.39/hour. The results of optimization using PSO produce a total thermal power of 400.75 MW and losses of 26.15 MW. The PSO method is able to reduce the cost of generating the South Sulawesi system by Rp11,118,312.07/hour or 7.9%. While using the ACO method generates a generation cost of Rp131,473,269.39/hour to generate power of 400,812 MW with losses of 26,219 MW. The ACO method is able to reduce the cost of generating the South Sulawesi system by Rp9,333,004.9/hour or 6.62%. PSO algorithm provides the lowest cost calculation of generator compared with conventional methods and ACO smart methods. This is also shown in the calculation process, the PSO method completes calculations faster than the ACO method.

Load Flow Analysis After the Entry of Renewable Power Plants in the Sulselrabar System

Power flow analysis in an electric power system is an analysis that reveals the performance of an electric power system and the flow of power (active and reactive) for certain conditions when the system is working. The analysis was carried out using the ETAP 16.00 software, the method used was the newton rapshon by taking a case study of normal conditions. From the results of the study, it can be seen that the power flow that occurs in each channel of the 150 kV system in the South Sulawesi system. The amount of active power (MW) that occurs during normal conditions based on the simulation is 1730.87 MW, where the active power is the largest, which is 171 MW from BUS15_TLASA to BUS13_SGMNSA. For the voltage data, there is a slight comparison of the voltage during the simulation compared to the PLN data.

Dynamic optimal power flow calculates intermittent wind turbine using ant colony method

Intermittent is electrical energy that is not available continuously due to uncontrollable external factors generated by a power plant which conditions vary in a reasonably short time scale. Intermittent can be limited or even mitigated by electricity storage, which is a rapidly growing area of research. In this research, the renewable energy used is the wind turbine. This study aims to schedule an economic generator by considering the intermittent wind turbine. Dynamic optimal power flow calculate Intermittent wind turbine uses ant colony method to determine the value of optimizing system operation with the integrated wind turbine. To determine the optimization value of the system operation, this study use a south sulawesi system consisting of 76 buses, 21 generators, and two wind power plant. From the results of the dynamic optimal power flow simulation, it is found that the generation costs are reduced from the real system costs using the ant colony method when the peak load time is 18.28% and the out peak load time is 18.08%, so that in only two times the ant colony optimization method, can reduce the cost of generation by Rp. 121,123,830.

Transmission Expansion Planning for the Optimization of Renewable Energy Integration in the Sulawesi Electricity System

In order to meet the growth in demand and the renewable energy integration target, the Sulawesi Electricity System (SES) should be expanded. Currently, the SES is divided into two systems, namely South and North Sulawesi. These two systems have different characteristics, such as the system size, reliability and operational cost. North Sulawesi is smaller, weaker and more expensive than the South System. In order to improve the system reliability, generation and transmission expansion planning should be executed simultaneously to meet the economical investment cost and satisfy the reliability standard. For this purpose, the necessity of a backbone system with a higher voltage level than the existing 150 kV system should be considered, including the interconnection option between the two existing systems in Sulawesi. A methodology based on economic and technical criteria was developed to determine the backbone voltage level. Two voltage level options were considered, namely 275 and 500 kV. Several criteria were considered in order to determine the backbone voltage level, including the economic voltage, the line-loading limit, N-1 contingency, short circuiting, transient stability, voltage stability and small signal stability. The backbone voltage candidates should fulfil all of the criteria. The simulation was conducted in base- and high-demand scenarios, considering the fluctuation of future economic growth. The load flow and the dynamic analysis were simulated in a DIgSILENT Power Factory environment. The results showed that the 275 kV backbone, which was built in 2022, would violate three criteria: the economic voltage, N-1 contingency and voltage stability. On the other hand, the 500 kV backbone voltage level fulfills all of the criteria. The result of this research was considered in the electricity planning documents in Sulawesi. From a technical and economical perspective, the 500 kV backbone was chosen for the SES.

Pengaruh PLTB Sidrap Terhadap Sistem Kelistrikan Sulawesi Selatan

New and renewable energy has become the green energy trend in the electric power system going forward. The Bayu Power Station (PLTB) is one of the centers of electricity generation with a primary source of energy that is pollution-free and environmentally friendly. Currently in the South Sulawesi system, PLTB has operated with a total power of 70 MW at a base load of around 700 MW. Because PLTB is very dependent on wind conditions, the power generated becomes unstable and this has a significant intermittent effect on the stability of the system. The results of this study indicate that the intermittent composition of nuclear power plants is increasing from the April-July 2018 period. This ever increasing contribution disrupts frequency stability in the South Sulawesi system

Effects of 500 kV EHV Transmission Lines on Location Determination and Capacity of Shunt Reactor in South Sulawesi Systems

Electricity in South Sulawesi system is so extensive that it is necessary to construct a 500 kV Extra High Voltage (EHV) to avoid instability and waste of electricity during the distribution of electricity. need. Therefore, this paper describes the implementation of research on optimizing the electrical energy network system from renewable energy power plants in the form of the application of extra high voltage transmission. This research was carried out as an effort to implement a 500 kV extra high voltage transmission in South Sulawesi. The length of the 500 kV EHV to be installed includes an extra-long transmission, which is 365 kms which will produce more voltage on the network during light loads. So, it is necessary to make efforts to improve the electrical system to meet applicable standards, including the addition of the shunt reactor. The purpose of this study is to obtain conclusions about the effect of the shunt reactor on the South Sulawesi transmission system after the 500 kV EHV is applied. The research that has been carried out aims to obtain the optimal location and capacity of a shunt reactor. The results of this study will be very useful for electricity stakeholders, especially transmission companies in South Sulawesi.

Small signal stability analysis due to the development of renewable energy generators in Sulawesi electricity

The problem of small signal stability is one of the main problems in the current power system because the purpose of operating the system is close to the limit. Small signal stability is important because small disturbances in the form of non-dampened electromechanical oscillations have limited the power flow limit in a steady state, so the oscillation will affect the operating system in a security and quality review. The entry of renewable energy in the Sulawesi interconnection system certainly has an impact on system stability and the emergence of electromechanical oscillations. An estimated 75 MW of power will come from the PLTB that will be built in Sidrap and 62.5 MW in Jeneponto. This study aims to analyze small signal stability due to the development of EBT generators on the Sulawesi interconnection system through eigenvalue characteristics and participation factors. The PLTB that will be integrated in the Sulawesi system certainly affects power flow which has an impact on small signal stability.

Stability Improvement by Reducing Voltage Fluctuation using SVC in Penetration Wind Power System

Currently, wind energy is a renewable energy that is growing because some of its advantages are connected to the grid system. This study is focus on presenting a probabilistic theory to design power system stability (PSS) and excitation of the FACTS system controller generator via Static Var Compensator (SVC) connected to wind turbines in Sidrap, region of South Sulawesi system. The purpose of the test system is on oscillation, profile voltage and influence stability of wind turbine penetration. An oscillating system requires system performance compensation from the side of the machine via PSS and transmission via SCV to increase the depth of the electro mechanical mode. So, the simulation results on 44 buses in the South Sulawesi system show the stability of the system and rapid voltage improvement and can reduce the oscillation that occurs. This system is tested using a time domain-based PSAT software simulation on the system.

Insertion of 275 kV Transmission Line for Improving the Voltage Profile and Efficiency of Electrical Power System

The location of electricity generation generally lies in the centers of renewable energy sources which are generally far from urban centers, such as in the province of South Sulawesi, Indonesia. This condition becomes a separate issue related to the quality of the voltage and the efficiency of the electrical system that uses 150 kV transmission lines to transmitted electrical energy from the power plants. Therefore, to avoid waste and lack of quality electricity, it is necessary to insert a new transmission line from these power plants to the city of Makassar. Where the transmission line built is 275 kV transmission line because it increases the voltage profile and is efficient compared to 150 kV transmission line even though the network is added to the bank’s capacitor. Therefore, this paper shows the reasons why a 275 kV transmission line was chosen for the improvement of voltage and reduction of power losses in South Sulawesi system.

Under Voltage Load Shedding Simulation for Southern Sulawesi Power System with Integration of Wind Power Plants

This paper discusses the simulation of under voltage load Shedding (UVLS) by considering the integration of wind power plants (WPP). The WPPs which will be integrated into the Southern Sulawesi interconnection system owned by PT. PLN (Persero) are located in the Sidrap area of approximately 70 MW using 30 wind turbines, generating 2.5 MW per turbine and in the Jeneponto area of about 62.5 MW capacity with the same number of wind turbines. Different wind conditions may affect the power system causing a major or minor disturbance, either in a release of generation or a transmission line. Based on this issue, this study aims to perform a simulation on areas that have voltage collapse when the WPPs are in the Southern Sulawesi system. The method of dynamic sensitivity presented in this paper. From the simulation and analysis results, it is obtained that load shedding locations in Makale, Palopo and Latuppa can stabilize the system’s voltage but causing the Poso area to be in an over voltage condition.

Electromagnetic field impact on 150 kV Raha-Baubau transmission line

The construction of 150 kV transmission line in Southeast Sulawesi is intended to establish interconnection with South Sulawesi system. The one of the transmission lines will be built 150 kV Raha-Baubau transmission line. One of the main potential impacts of the transmission line is electromagnetic field radiation. The value of electromagnetic field generating by transmission line can be conducted by calculation and simulation as studied in this research. This research was used shadow conductor approach method. The calculation and simulation results were showed that the largest electric field value occurring at two coordinates points (-7,2) and (7,2) with 0.366778 kV/m. The largest magnetic field was happening at coordinate (0,2) with 3.186838 A/m or 0.004 mT. Both electric and magnetic field radiation were still below the specified standard value, 5 kV/m for the electric field and 0.1 mT for the magnetic field.

Tropical climate effects on corona power losses on 275 kV transmission lines in the South Sulawesi system

Tropical climate effects on corona power losses on 275 kV transmission lines in the South Sulawesi system

Allometric relationships of frequently used shade tree species in cacao agroforestry systems in Sulawesi, Indonesia

Shade trees play an important role within agroforestry systems by influencing radiation and wind regimes as well as nutrient and hydrological cycling. However, there is a lack of quantitative assessments of their functions. One of the reasons is the rare information on structural characteristics of shade tree species. Therefore, the aim of this study is to provide basic information on the structure of frequently used shade tree species for the implementation of models simulating the ecosystem processes in agroforestry systems. The investigation of the shade trees was conducted at two cacao agroforestry sites on Sulawesi, Indonesia. The measurements of the main structural parameters: diameter at breast height, tree height, trunk height, crown length and crown radius were carried out for the shade tree species Aleurites moluccana, Cocos nucifera and Gliricidia sepium. For data collection, the National Forest Inventory Field Manual Template by FAO (2004) was applied. Based on this information allometric functions were derived for the correspondent shade tree species. The best significant relationships were obtained for the height-crown length relationship of the dicotyledonous tree species’ A. moluccana and G. sepium with a coefficient of determination r² = 0.925 and r² = 0.738, respectively, and the height-crown length relationship of the monocotyledonous palm C. nucifera with r² = 0.663. The transferability tests ‘analysis of covariance’ and ‘homogeneity of slopes’ have shown that the obtained allometric functions are also applicable to other cacao agroforestry systems of the region.

Statistical Analysis of Mercury Data from Soil Survey in Non-volcanic Geothermal System: A Case Study in Sulawesi

Mercury analysis from soil survey is one of the standard methods in geothermal exploration surveys conducted by Center for Survey and Geological Data or PSDG (formerly DIM). The objective of this paper is to analyze thresholds of four non volcanic geothermal systems in Sulawesi, i.e. Suwawa, Marana, Pincara and Mangolo. The value of Hg (ppb) is differ from one prospect to another. Its value ranges from tens ppb up to few thou sands ppb, depends on the geology and geothermal system; in high temperature volcanic geothermal system, or in non-volcanic geothermal system. Therefore determination of threshold that separate background and anomaly is important for better delineation of Hg anomaly area. Prior to threshold determination, a probability plot is used to examine the normality and the existence of sub population within the data. Sub population located at the end left of probability graph or sub population with the lowest range value is assumed containing the background and threshold information. The threshold is then calculated using mean plus one standard deviation of data within this sub population. Comparison of the calculated number with the published threshold value shows very significant difference in term of anomaly area coverage for further exploration target. This paper demonstrates Exploratory Data Analysis (EDA) techniques that can be applied as a tool to determine threshold value. The results suggest that this statistical methodis able to assist and support a better threshold value determination.

Spider web guilds in cacao agroforestry – comparing tree, plot and landscape‐scale management

AbstractAim Owing to their role as insect predators, web‐building spiders can be important biological control agents within agricultural systems. In complex tropical agroecosystems such as agroforests, management determines plant architecture, vegetation composition and associated ant density, but little is known on how these attributes, together with landscape context, determine spider web density. We hypothesized that all three spatial scales and the presence of Philidris ants significantly contribute to the explanation of spider web density with web types being differently affected.Location In 42 differently managed cacao agroforestry systems in Sulawesi, Indonesia.Methods We surveyed the distribution of five spider‐web types on 420 cacao trees to determine how these relate to habitat variables and a numerically dominant ant species at three different spatial scales, comparing tree, plot and landscape features. We fitted linear mixed‐effects model, selected the best model subset using information‐theoretic criteria and calculated the model‐averaged estimates. We used non‐metric multidimensional scaling (NMDS) to determine and visualize guild level responses to the effects of the tree, plot and landscape‐scale variables.Results The five spider guilds preferred different features of cacao tree architecture. Most frequently recorded webs belonged to the line‐ and orb‐web type. At the tree scale, overall web density was positively related to canopy openness. At the plot scale, a higher number of shade trees was related to a higher web density. At the landscape scale, the altitude determined the distribution patterns of web‐building spiders. Presence of Philidris ants was positively associated with density of orb webs, while no pattern was found for other web types.Main conclusions Results suggest spider web density could be increased by pruning of cacao trees while keeping shade trees at high density in cacao plots. The results emphasize the need to consider scale dependency of crop management and web‐guild‐specific responses that may be related to different functional roles of spiders as a high‐density predator group in agroforestry.