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Abstrak :
[ABSTRAK
Microgrid (Jaringan Listrik Mikro/JLM) adalah system pembangkit terdistribusi menggunakan beberapa sumber energi sebagai sumber energi listrik, antara lain, dari sumber energi terbarukan, sehingga ramah lingkungan. JLM dapat bekerja terhubung dengan grid ataupun bekerja secara terpisah dari grid/isolated. Stabilitas sistem JLM memberikan reliabilitas, kualitas daya dan efesiensi daya listrik yang lebih baik. Pada JLM yang menggunakan sumber energi surya maka ada satu kondisi dimana pada saat kondisi islanding (tidak terhubung pada jaringan utilitas/PLN) dan pembangkit tidak mendapatkan pasokan energi surya, seperti pada saat malam hari, maka hanya menggunakan baterai sebagai sumber energinya. Hal ini menimbulkan permasalahan lain yaitu bagaimana melakukan pengaturan operasi baterai dari masing-masing pembangkit, dengan tetap dapat menjaga kontinuitas penyaluran daya ke beban sehingga setiap pembangkit tetap mampu menyalurkan daya tanpa harus dilakukan pemutusan beban karena kekurangan pasokan energi dari baterai atau jika dilakukan pemutusan beban maka dipastikan paling minimal. Dengan pola pengaturan operasi yang dilakukan pada saat pembangkit beroperasi menggunakan baterai, disetiap akhir siklus operasinya, selain seluruh beban dapat dipasok daya,juga tercapai kondisi level baterai maksimum. Untuk menyelesaikan permasalahan diatas maka dibuat metode pembagian daya antar inverter pada aplikasi manajemen energi di JLM-PV yang mengatur operasi penggunaan baterai cadangan di setiap pembangkit terdistribusi agar dapat menjaga kontinuitas pasokan daya atau minimalisasi besaran beban yang harus diputus, dengan menggunakan zero one integer programing. Pada setiap pembangkit guna memenuhi kebutuhan daya dari beban dengan mekanisme pengaturan pembagian penyaluran daya lisrik (power sharing) antar pembangkit serta melakukan pemanfaatan sumber energi yang berasal dari radiasi matahari secara maksimal, berdasarkan data perkiraan beban dan perkiraan radiasi. Dari hasil penelitian menunjukan penerapan mekanisme optimasi pemutusan beban menggunakan zero-one integer programming pada permasalahan diatas dapat meningkatkan IPD (indek penyaluran daya) dari 86,65% menjadi 95,75% pada simulasi 5 pembangkit dengan metode pembagian daya berdasarkan mode operasi kesamaan daya inverter. Sementara berdasarkan mode operasi kesamaan level baterai penerapan optimasi pemutusan beban meningkatkan IPD dari 95,86% menjadi 99,20%.;

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ABSTRACT
Microgrid is a distributed generation system using multiple energy sources, such as, renewable energy sources, that making it environmentally friendly. Microgrid is able to work connected to grid (on grid) or disconnected to grid (off grid/isolated). Microgrid system provides better reliability, power quality and power efficiency. On solar energy microgrid,during the islanding condition and no solar radiation, at night, it only use the battery as a source of energy. This condition raises another problem of how to manage battery operation of each generation to maintain the continuity of the power distribution to each load so that each generation is still able to distribute power without load shadding due to insufficient of energy supply from the battery or if load shedding is done, it must be done at the most minimum. By performing operation management of the generation when supplied using the battery, the entire load can be supplied with power and the battery reached the maximum level, at the end of every operation cycle. To solve the aforementioned problem, the inverter power sharing method is developed in energy management application on PV-microgrid, which will manage the usage of back-up battery operation on each distributed generation in order to maintain the continuity of power distribution or to minimize the amount of load shedding, by using the zero one integer programming. To meet the load power requirements with generated power and to maximizing the use of solar radiation energy, each generation, using power sharing control mechanism based on data of load prediction and forecasting of solar radiation. The result of the research shown that implementation of the load shedding optimization mechanism using zero-one integer programming on the aforementioned problem, can increase the PDI (Power Distribution Index) from 86,65% to 95,75% at 5 generation simulation, with power sharing method based on Equal Inverter Output Power Operation Mode. Meanwhile, power sharing method based on Equal Battery Level Operation Mode, the implementation of load shedding optimization increases PDI from 95,86% to 99,20%., Microgrid is a distributed generation system using multiple energy sources, such as, renewable energy sources, that making it environmentally friendly. Microgrid is able to work connected to grid (on grid) or disconnected to grid (off grid/isolated). Microgrid system provides better reliability, power quality and power efficiency. On solar energy microgrid,during the islanding condition and no solar radiation, at night, it only use the battery as a source of energy. This condition raises another problem of how to manage battery operation of each generation to maintain the continuity of the power distribution to each load so that each generation is still able to distribute power without load shadding due to insufficient of energy supply from the battery or if load shedding is done, it must be done at the most minimum. By performing operation management of the generation when supplied using the battery, the entire load can be supplied with power and the battery reached the maximum level, at the end of every operation cycle. To solve the aforementioned problem, the inverter power sharing method is developed in energy management application on PV-microgrid, which will manage the usage of back-up battery operation on each distributed generation in order to maintain the continuity of power distribution or to minimize the amount of load shedding, by using the zero one integer programming. To meet the load power requirements with generated power and to maximizing the use of solar radiation energy, each generation, using power sharing control mechanism based on data of load prediction and forecasting of solar radiation. The result of the research shown that implementation of the load shedding optimization mechanism using zero-one integer programming on the aforementioned problem, can increase the PDI (Power Distribution Index) from 86,65% to 95,75% at 5 generation simulation, with power sharing method based on Equal Inverter Output Power Operation Mode. Meanwhile, power sharing method based on Equal Battery Level Operation Mode, the implementation of load shedding optimization increases PDI from 95,86% to 99,20%.]

Abstrak :
ABSTRAK
Harmonisa dan dampaknya didalam sistem daya listrik semakin meningkat akibat penggunaan peralatan listrik yang dikendalikan dengan perangkat elektronik dan perangkat lainnya penghasil frekwensi tinggi. Satu hal penting yang diperhatikan didalam mengevaluasi dampak harmonisa adalah efek harmonisa pada komponen sistem daya listrik. Transformator adalah perangkat utama didalam sistem daya listrik. Meningkatnya harmonisa didalam sistem daya menyebabkan kenaikan rugi daya listrik didalam kumparan transformator dan menurunkan kemampuannya dalam membatasi penyebaran aliran harmonisa triplen. Dalam perkembangan teknologi transformator peredam distorsi harmonisa terdapat berbagai tipe konfigurasi hubungan kumparan untuk berbagai kondisi pembebanan diantaranya adalah transformator Vee/vee, T-Scott, Le Blanc, Dy (delta-wye) atau Dz (delta-zigzag). Berdasarkan literatur dan simulasi pembebanan transformator tersebut diketahui bahwa transformator tersebut belum optimal menghambat penyebaran aliran harmonisa triplen ke sisi sumber. Dalam disertasi ini transformator delta primer ? transposisi zigzag sekunder (Dtz) dimodelkan berdasarkan tiga prinsip penghambatan induksi medan elektromagnetik, yaitu prinsip pertama menyeimbangkan induksi fluks magnetik; dan prinsip kedua penghambatan fasa fluks harmonisa; serta prinsip ketiga menyirkulasikan sisa induksi fluks magnetik harmonisa. Transposisi kumparan zigzag dilakukan dengan membagi setiap kumparan fasa sekunder menjadi tiga bagian identik dan meletakkannya pada ketiga kaki yang berbeda. Hal ini bertujuan untuk menyeimbangkan induksi fluks magnetik arus harmonisa triplen dari beban nonlinier satu fasa. Kelebihan tambahan transposisi zigzag dapat memperbesar impedansi dalam rangkaian transformator pada saat band frekwensi harmonisa triplen sehingga magnitude arus harmonisa triplen dapat diturunkan. Dengan semakin sedikitnya arus harmonisa triplen maka induksi ggm (ampere.lilitan) beban didalam kumparan delta primer akan turun. Hasilnya, magnitud arus harmonisa triplen yang bersirkulasi menurun sehingga tidak mendistorsi tegangan dan arus di sisi sumber. Dalam penelitian pada disertasi ini dilakukan simulasi untuk arus arus harmonisa triplen yang dibangkitkan didalam kumparan primer dan sekunder transformator Dtz. Pengujian pembebanan pada sistem tiga fasa dilakukan untuk kondisi beban seimbang maupun beban tidak seimbang. Dari eksperimen dan simulasi dapat ditunjukkan bahwa tingkat distorsi (THD) arus harmonisa didalam kumparan sekunder pada kondisi beban seimbang adalah 70,8%, dan di sisi primer adalah 24,3%. Sedangkan untuk kondisi beban tidak seimbang, tingkat distorsi (THD) didalam kumparan sekunder adalah 68,44% dan di sisi delta primer adalah 26,4%. Hal ini menunjukkan bahwa transformator Dtz memiliki kemampuan filter untuk menurunkan THD arus sebesar 42 ? 46% untuk kondisi beban seimbang dan tidak seimbang, dengan kata lain menghambat arus harmonisa triplen mengalir ke sisi sumber, sehingga sangat cocok untuk diterapkan pada beban beban yang banyak menghasilkan harmonisa triplen terutama di industri. Dengan membandingkan hasil simulasi komputer dengan data pengukuran melalui eksperimen laboratorium, ini dibuktikan bahwa penggunaan transformator Dtz adalah salah satu metode untuk menurunkan arus harmonisa dan menghambat aliran harmonisa ke sisi sumber.

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ABSTRACT
Harmonics and their impacts in the electric power system have increased due to the use of electrical equipments which are controlled by the electronic devices and other devices generating high frequency. One of important considerations when evaluating the impact of harmonics is their effects on the power system components and loads. Transformers are the major components in the electrical power systems. The increasing of harmonic level in power systems may cause the increasing of power losses in the transformer winding and in turn will reduce its ability to limit the triplen harmonics current flow to the distribution system. There are various types of harmonic filter-capable transformers for various loading conditions such as Vee/vee, T-Scoot, Le Blanc, Dy (delta-wye) and Dz (delta-zigzag) transformer. Based on review on literature and simulation of transformer loading, it can be concluded that those transformers have limitation on inhibiting the spread of the triplen harmonics current into the source side in the delta winding. In this dissertation, delta primary - transposed zigzag secondary (Dtz) winding transformer is modeled based on the three basic electromagnetic inductions. First balance the magnetic flux induction, followed by suppression the phase of harmonics flux, and circulating the remaining magnetic flux harmonic. Transposition of the zigzag winding is done by dividing equally each secondary winding and laid the three into different legs. This is to balance triplen harmonic magnetic flux from the single phase nonlinear load. The additional advantages of the zigzag transposition can enhance internal impedance of its transformer at its triplen harmonics frequency band so that triplen harmonics current can be reduced. With it reducing triplen harmonic current, mmf load induction (ampere.turn) in delta primary can be reduced. The result is reducing magnitude of triplen harmonic circulation and eliminating distortion in the source. The triplen harmonics currents generated on the primary and secondary winding of D tz transformer are simulated in this research of dissertation. Both balanced and unbalanced loads of the three-phase distribution system are examined. The experiment shows that the total THD current in the secondary winding when balanced loads are applied is about 70.8 %, and in the primary side is 24.3 %. While for unbalanced loads, the average THD in secondary winding is 68.44 % and in delta winding is 26.4 %. It means the Dtz transformer has a filter-ability to reduce about 42 - 46 % THD for both balanced and unbalanced loads. This means suppressing triplen harmonics from flowing to the source and thus suitable to apply it to nonlinear load found in industry. Comparing the computer simulation results and data measurements through experiment in the laboratory, it is proved that the use of the proposed Dtz transformer is one of the methods to reduce harmonic currents and inhibit them to enter to the supply system.