Thunderstorm Algorithm for Determining Unit Commitment in Power System Operation

Solving the unit commitment problem is an important task in power system operation for deciding a balanced power production between various types of generating units under technical constraints and environmental limitations. This paper presents a new intelligent computation method, called the Thunderstorm Algorithm (TA), for searching the optimal solution of the integrated economic and emission dispatch (IEED) problem as the operational assessment for determining unit commitment. A simulation using the IEEE-62 bus system showed that TA has smooth convergence and is applicable for solving the IEED problem. The IEED's solution is associated with the total fuel consumption and pollutant emission. The proposed TA method seems to be a viable new approach for finding the optimal solution of the IEED problem

Evaluation of Power Distribution based on Power Losses on Transmission Interconnection

This paper discusses the analysis of continuity of power delivery and network losses in the scenario of adding 150 kV to the Malang Raya transmission network. The discussion in this paper is based on the increasing load growth conditions in Malang Raya and the condition of the Malang 150 kV main system which is centralized in the Kebonagung Substation so that a scenario of adding 150 kV transmission network interconnection is needed to increase the capacity, reliability, and improvement of the Malang Raya system. Based on the simulation results before the scenario of adding 150 kV transmission network losses in the poor 150 kV main system by 0.02 MW, whereas after the scenario of adding 150 kV transmission network the overall losses in the 150 kV main unfortunate main system were 0.009 MW

Pengaruh Effluent Sapi Terhadap Beberapa Sifat Fisik Dan Kimia Tanah Pada Lahan Ultisol Di PT Great Giant Pineapple Lampung Tengah

Effluent sapi adalah pupuk organik tanah yang berasal dari limbah cair campuran kotoran sapi padat, urin, air dan sisa kandang lainnya. Kandungan unsur kimia yang terdapat pada effluent sapi diharapkan dapat memperbaiki sifat fisik dan kimia tanah. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian effluent sapi terhadap beberapa sifat fisik dan kimia tanah pada ultisol di PT Great Giant Pineapple. Hipotesis yang diajukan yaitu pemberian effluent sapi memberikan pengaruh positif dan semakin tinggi taraf perlakuan yang diberikan semakin besar pengaruhnya dalam memperbaiki sifat fisik dan kimia tanah. Penelitian dilaksanakan pada bulan September hingga bukan November 2014 pada lahan Ultisol di PT Great Giant Pineapple lokasi 90A. Penelitian ini menggunakan Rancangan Acak Lengkap dengan faktor perlakuan penelitian yaitu effluent sapi dengan taraf perlakuan 0 lha -1 , 200.000 lha -1 , 300.000 lha -1 , dan 450.000 lha -1 . Variabel pengamatan sifat fisik meliputi stabilitas agregat tanah dan kekuatan tanah, sedangkan sifat kimia meliputi pH tanah H 2 O, C-Organik, N-Total serta Nisbah C/N. Data yang diperoleh dari hasil analisis laboratorium kemudian dianalisis menggunakan Analisis Ragam dan dilanjutkan dengan Uji BNT pada taraf = 0,05. Data tersebut kemudian juga diharkatkan berdasarkan kriteria tertentu. Hasil penelitian menunjukkanbahwa aplikasi effluent sapi berpengaruh positif dalam memperbaiki stabilitas agregat tanah dan pH tanah, namun tidak berpengaruh terhadap C-Organik, N-Total, maupun nisbah C/N tanah. Aplikasi effluent sapi sampai dengan taraf 450.000 l ha -1 masih cukup rendah dan belum efisien untuk meningkatkan C-Organik, N-Total, maupun nisbah C/N tanah

Kajian Sifat Fisik Tanah Pada Lahan Pertanaman Nanas (Ananas Comosus L.) Produksi Tinggi Dan Rendah Di PT Great Giant Pineapple Lampung Tengah

Dalam penyiapan lahan untuk tanaman nanas, PT GGP menerapkan olah tanah intensif yang lama kelamaan dapat menimbulkan dampak negatif diantaranya adalah penurunan kualitas fisik tanah. Hal ini dapat dipengaruhi oleh banyak faktor seperti meningkatnya kepadatan tanah akibat adanya tekanan dari alat – alat pertanian. Degradasi sifat fisik tanah berpengaruh terhadap Perubahan Perubahan kualitas sifat fisik seperti meningkatnya kepadatan dan kekuatan tanah serta menurunkankapasitas infiltrasi dan kemampuan tanah menahan air. Penelitian ini bertujuan untuk mengkaji karakteristik sifat fisik tanah pada lahan yang menghasilkan produksi rendah dan lahan yang menghasilkan produksi tinggi di lahan pertanaman nanas di PT Great Giant Pineapple Terbanggi Besar Lampung Tengah. Penelitian ini di laksanakan pada bulan Juni sampai dengan September 2014 pada areal pertanaman nanas (Ananas comosus) di lokasi 26B PT Great Giant Pineapple Terbanggi Besar Lampung Tengah. Metode yang digunakan pada penelitian ini adalah metode survei. Pengambilan sampel tanah dilakukan pada lokasi 26B dengan luas areal kurang lebih 8,30 ha. Penentuan titik pengambilan sampel tanah dilakukan dengan metode diagonal. Hasil penelitian menunjukkan bahwa nilai kerapatan isi dan kekuatan tanah pada lahan pertanaman nanas yang menghasilkan produksi rendah lebih besar (kualitasnya lebih buruk) dibandingkan pada lahan yang menghasilkan produksi tinggi. Laju infiltrasi pada lahan pertanaman nanas yang menghasilkan produksi rendah lebih lambat dibandingkan pada lahanyang menghasilkan produksi tinggi. Kompaksi berpengaruh terhadap menurunnya kualita sifat fisik tanah seperti meningkatnya kepadatan dan kekuatan tanah, serta menurunkan kapasitas infiltrasi dan kemampuan tanah menahan air. Degradasi sifat fisik tanah yang ditimbulkan seperti rusaknya struktur dan agregat tanah, berkurangnya ruang pori tanah, meningkatnya kerapatan isi dan kekuatan tanah serta menurunnya kapasitas infiltrasi tanah dapat mempengaruhi produktivitas tanaman menjadi tidak optimal

Stimulasi Keterampilan Argumentasi Mahasiswa Calon Guru Biologi Menggunakan Variasi Pertanyaan dalam Grup Diskusi Facebook

In the context of online learning environments, the argumentation skill becomes an important priority for sustained engagement of students in productive negotiation of ideas and evidence based reasoning (Siakidou, Papadouris, & Constantinou, 2014). The aim of this study is to reveal the quality of argumentation skills stimulation used a variety of questions in Facebook group discussion for Biology student teachers. The method of this work was using quasi experiment with time series design. This study involved 24 Biology student teachers who contacted in online and expressed willingness to take part in Facebook group discussions. Results indicate that divergence questions types have a greater influence on the argumentation skills quantity rather than focal and brainstorming questions types, while the focal question types have a greater influence on the quantity of argumentation skills rather than brainstorming questions types. In addition, this study shows that brainstorming questions types (FA) have a better effect to coding scheme for individual arguments rather than focal questions types (NFA) and the divergent questions types (NJA) to stimulating the quality of argumentation skills of Biology student teachers. Further research to uncover the effect of topic discussion on the arguments quality is expected to enrich the findings in this study

Demand Forecasting Considering Actual Peak Load Periods Using Artificial Neural Network

Presently, electrical energy consumption continues to increase from year to year. Therefore, a short-term load forecasting is required that electricity providers can deliver continuous electrical energy to electricity consumers. By considering the estimation of the electrical load, the scheduling plan for operation and allocation of reserves can be managed well by the supply side. This study is focused on a forecasting of electrical loads using Artificial Neural Network (ANN) method considering a backpropagation algorithm model. The advantage of this method is to forecast the electrical load in accordance with patterns of past loads that have been taught. The data used for the learning is Actual Peak Load Period (APLP) data on the 150 kV system during 2017. Results show that the best network architecture is structured for the APLP Day and Night. Moreover, the momentum setting and understanding rate are 0.85 and 0.1 for the APLP Day. In contrast, 0.9 and 0.15 belong to the APLP Night. Based on the best network architecture, the APLP day testing process generates Mean Squared Error (MSE) around 0.04 and Mean Absolute Percentage Error (MAPE) around 4.66%, while the APLP Night generates MSE in 0.16 and MAPE in 16.83%

Preferensi Sivitas Akademika Universitas Trunojoyo Madura Terhadap Moda Penyeberangan Surabaya-madura

The Suramadu Bridge is a bridge that connects the island of Java in Surabaya with Madura Island in Kamal, Bangkalan, and that crosses Madura Strait. The Suramadu Bridge has a length of 5,438 meters, which is the longest bridge in Indonesia. The construction of the Suramdu Bridge wass intended to accelerate development in Madura Island which covers the economy and infrastructure in the Madura Region, which wass still relatively underdeveloped compared to other areas in East Java. Although the bridge has been serving people, many academicians of Trunojoyo University still choose feri services as a mode for crossing towards Madura and vice versa. This study aims to investigate the preferences of the academicians of Trunojoyo University in selecting transportation mode for traveling Surabaya-Madura. This study was conducted by interviewing some academicians who are traveling to Madura using the feri mode. The results show that there are some preference attribution which the academicians choose feri services namely security, closer location, higher accessibility, and comfor

Current Ripple Analysis of New Double-Stator AC Drive Systems

This paper presents a current ripple analysis of new double-stator AC drive system. At first, a new double-stator AC drive system is proposed. The aim is to combine the benefits both the multilevel and multiphase system to provide the better performance to drive AC motor. The input and output current ripples of the proposed AC drive system are then analyzed. The current ripples of the proposed AC drive system are then compared to the ones of conventional double-stator AC drive system. Under the same DC input voltage, it is shown that the proposed results in less output current ripple. Under the same output voltage, the proposed AC drive system results in smaller input current and, therefore, fewer losses on the DC power supply. Experimental results are included to show the validity of the proposed concept