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| Author(s): |
Fabiano Gustavo Silveira Magrin
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: | 2017-03-24 |
| Examining board members: |
Maria Cristina Dias Tavares;
Eduardo Cesar Senger;
Mário Oleskovicz;
Carlos Alberto de Castro Junior;
Daniel Dotta
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| Advisor: | Maria Cristina Dias Tavares |
| Abstract | |
The power transformer is the most expensive equipment in a substation and some types of faults as inter-turn and turn-to-ground faults cannot be detected by the actual protection relays as fast as they should and with safety. Both micro processed based relays and mechanical relays, as gas relays, fail to promptly detect internal faults. Therefore, this work proposes new fault detection methodologies for a fast and effective transformer protection. For the development of the new algorithms, this work presents the behavior of the currents, voltages and impedances measured/calculated from all sides of the transformer for external and internal faults. Analyzing all generated data, it was possible to develop two protection elements, being the first based only on current measurements, and the second uses voltages and currents from all sides of the transformer. Both elements presented a satisfactory sensitivity to detect transformer internal faults. The algorithms were developed and implemented in a real-time digital simulator through C language. Both were tested to assure speed, selectivity, security, reliability and mainly sensitivity. When necessary, blocking and releasing algorithms were developed to assure the above-mentioned properties. Eventually the elements were compared to existing protection relay elements as phase differential and negative sequence differential. The tests showed an improvement compared to the existing algorithms. In the last part of the work, one of the elements was implemented in a commercial relay hardware and its response equals to the software version. The element programmed inside the relay works as a prototype and could be installed in the field. This work showed to be possible to increase the sensitivity to detect internal faults in power transformers (AU) | |
| FAPESP's process: | 14/06232-3 - New methodology for transformer protection |
| Grantee: | Fabiano Gustavo Silveira Magrin |
| Support Opportunities: | Scholarships in Brazil - Doctorate |