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| Author(s): |
Javier Arturo Santiago Ortega
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Elétrica e de Computação |
| Defense date: | 2019-05-17 |
| Examining board members: |
Maria Cristina Dias Tavares;
Washington Luiz Araujo Neves;
Maria Teresa Nunes Padilha de Castro Correia de Barros;
Antonio Carlos Siqueira de Lima;
Patricia Mestas
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| Advisor: | Maria Cristina Dias Tavares |
| Abstract | |
Half-wavelength transmission lines are an alternating current alternative for very long-distance power transmission because of their good transmission properties. However severe overvoltages due to critical faults still need an adequate solution. The present research analyzes this problem in detail and proposes a mitigation method for reducing the overvoltages. First, a study of the mechanism of overvoltage generation shows that because of the long line length there are two regions in which the application of faults involving the positive and negative sequences promotes fundamental frequency resonance. This disturbance, with similar behavior to a typical series resonance, produces critical overvoltage profiles along the entire line, with maximum values of several times the nominal value, high rate of rise and predominantly sustained response. Overvoltages of such characteristics are not observed in lines with typical lengths and would have a negative impact on the power system, which is why a fast mitigation method is required. Thus, the requirements of the system for the mitigation of overvoltages due to critical faults are established by a throughout research and some mitigation alternatives are evaluated. It is identified that the options based on spark gaps are the most adequate due to the reduction of the overvoltage in magnitude and duration. This option allows to remove the resonance condition by modifying the network topology with a relatively fast response time. Finally, a method based on two spark gaps is evaluated in more detail, observing changes in the characteristics of the overvoltages. The overvoltages lose the sustained characteristic, becoming transient in nature, with important reductions in the magnitudes and the extension of the affected region (AU) | |
| FAPESP's process: | 15/13823-0 - MITIGATION PROCEDURE TO FAULT OVERVOLTAGES IN HALF WAVELENGTH TRANSMISSION LINES |
| Grantee: | Javier Arturo Santiago Ortega |
| Support Opportunities: | Scholarships in Brazil - Doctorate |