Inisiasi Feroresonansi pada Transformator Tegangan Rendah

Wahyudi, Mochammad (2018) Inisiasi Feroresonansi pada Transformator Tegangan Rendah. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Feroresonansi merupakan sebuah interaksi pada inti transformator yang menimbulkan tegangan abnormal. Kemunculan feroresonansi sangat dipengaruhi oleh parameter dan kondisi sistem. Dalam memahami karakteristik tersebut secara fisik, pengujian inisiasi feroresonansi dilakukan pada transformator tegangan rendah satu fasa dan tiga fasa. Variasi tegangan sumber dan kapasitansi diberikan pada transformator satu fasa, sedangkan variasi pelepasan fasa dan kapasitansi serta ketidaksimetrisan kaki inti diberikan pada transformator tiga fasa. Respon tegangan primer transformator, meliputi bentuk gelombang, magnitudo, dan harmonisa, dianalisis. Diagram bifurkasi digunakan untuk mengenali secara lebih mudah karakteristik feroresonansi terhadap variasi tegangan sumber, sedangkan fast fourier transform (FFT) digunakan untuk mendapatkan spektrum harmonisa yang akan menunjukkan mode feroresonansi. Kemudian total harmonic distortion (THD) dihitung berdasarkan spektrum harmonisa tersebut untuk mengetahui tingkat harmonisa tegangan ketika kondisi feroresonansi. Hasil pengujian menunjukkan bahwa faktor inisiasi yang diberikan mampu menunjukkan respon feroresonansi dengan efek yang berbeda. Efek feroresonansi yang berbahaya (tegangan lebih dan harmonisa tinggi) dijumpai pada pengujian transformator satu fasa dengan kapasitansi 50 uF, 80 uF, dan 100 uF. Sementara itu, pengujian transformator tiga fasa dengan variasi kapasitansi memberikan efek feroresonansi yang lebih berbahaya (tegangan lebih) daripada variasi pelepasan fasa (tegangan kurang). Keanehan respon feroresonansi lebih mudah diamati pada fasa S yang memiliki kaki inti lebih besar daripada dua fasa lainnya. Lonjakan nilai dan distorsi bentuk gelombang secara signifikan akibat peningkatan tegangan sumber sekitar 1 V (jump phenomenon) ditemui pada pengujian transformator satu fasa dengan kapasitansi 80 uF dan 100 uF. Respon gelombang tegangan primer transformator yang diperoleh diidentifikasi sebagai mode fundamental. Melalui penelitian ini, inisiasi dan karakteristik feroresonansi diharapkan agar mampu dipahami secara lebih baik melalui pendekatan fisik. =============== Ferroresonance is an interaction on transformer core that creates abnormal voltage. The appearance of feroresonance is highly affected by parameter and condition of system. In order to understand its characteristic physically, ferroresonance initiation experiment was conducted to a low voltage single phase transformer and a low voltage three phases transformer. The variations of voltage source magnitude and capacitance were given to the single phase transformer, while the variations of opened phases (opening of switch) and capacitance as well as unsymmetrical core leg were applied to the three phases transformer. The response of transformer primary voltage including waveform, magnitude, and harmonics was then analyzed. Bifurcation diagram was employed to understand easier the ferroresonance’s characteristics to voltage source variation, whereas fast fourier transform (FFT) was used to obtain harmonics spectrum that will explain ferroresonance mode. Total harmonics distortion (THD) was then calculated based on the harmonics spectrum in order to know the level of harmonics during ferroresonance condition. The experimental results showed that the initiation factors given to both of transformers created ferroresonance response with different effects. The most dangerous response (high level of overvoltage and harmonics) was seen in the experiment of single phase transformer with capacitance of 50 uF, 80 uF, and 100 uF. In addition, the experiment of three phases transformer with capacitance variations resulted in more dangerous effect (overvoltage) than experiment with opened phases (undervoltage). The abnormal responses were observed more clearly in the S phase with its greater core leg than the others. Jump phenomenon that was indicated by a significant increase of magnitude and distortion of transformer primary voltage due to a little increase of voltage source about 1 V was seen in the experiment of single phase transformer with capacitance of 80 uF and 100 uF. The responses of ferroresonance for all experimental results were identified as fundamental mode. By this experiment, the ferroresonance characteristics and initiations were expected to be understood more clearly, especially its physical mechanism.

Item Type: Thesis (Masters)
Uncontrolled Keywords: diagram bifurkasi; fast fourier transform (FFT); inisiasi dan karakteristik feroresonansi; ketidaksimetrisan kaki inti; variasi tegangan sumber; kapasitansi; dan pelepasan fasa; bifurcation diagram; fast fourier transform (FFT); initiation and characteristic of ferroresonance; unsymmetrical core leg; variation of voltage source; capacitance; and opened phases.
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK201 Electric Power Transmission
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK3226 Transients (Electricity). Electric power systems. Harmonics (Electric waves).
Divisions: Faculty of Industrial Technology > Electrical Engineering > (S2) Master Theses
Depositing User: Wahyudi Mochammad
Date Deposited: 19 Feb 2018 02:45
Last Modified: 19 Feb 2018 02:45
URI: http://repository.its.ac.id/id/eprint/49221

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